TITLE 'rxdos bios interface drivers' PAGE 59, 132 .LALL ;'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''; ; Real Time Dos ; ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -; ; ; ; This material was created as a published version of a DOS ; ; equivalent product. This program logically functions in ; ; the same way as MSDOS functions and it is internal data ; ; structure compliant with MSDOS 6.0 ; ; ; ; This product is distributed AS IS and contains no warranty ; ; whatsoever, including warranty of merchantability or ; ; fitness for a particular purpose. ; ; ; ; ; ; (c) Copyright 1990, 1997. Api Software and Mike Podanoffsky ; ; All Rights Reserved Worldwide. ; ; ; ; This product is protected under copyright laws and may not ; ; be reproduced in whole or in part, in any form or media, ; ; included but not limited to source listing, facsimile, data ; ; transmission, cd-rom, or floppy disk without the expressed ; ; written consent of the author. ; ; ; ; License for distribution for commercial use or resale ; ; required from: ; ; ; ; Api Software ; ; 12 South Walker Street ; ; Lowell, MA 01851 ; ; ; ; internet: mikep@world.std.com ; ; ; ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -; ; Compile with MASM 5.1 ; ;...............................................................; include rxdosmac.asm include rxdosdef.asm ;'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''; ; RxDOSBIO.SYS ; ;...............................................................; RxDOSBIOS SEGMENT PARA PUBLIC 'CODE' assume cs:RxDOSBIOS, ds:RxDOSBIOS, es:RxDOSBIOS, ss:RxDOSBIOS ;'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''; ; Load remainder of RxDOS ; ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -; ; ; ; When rxdosbio.sys is loaded by the disk boot loader, it ; ; loads automatically the first three sectors regardless of ; ; the cluster allocation. For RxDOS, only the first sector in ; ; a cluster needs to actually be loaded. This loads this ; ; portion of the rxdosbio.sys code, which loads the remainder ; ; of the program using FAT allocations. ; ; ; ; The boot program has also detected and read the first sector ; ; of the root directory which is located at 0000:0500 (that ; ; is, 50:0). ; ; ; ; Boot sequence is ; ; ; ; MBR (master boot record) ; ; loads at 0:7c00, relocated to 60:0 ; ; located at physical address cyl: 0 head: 0 sector: 1 ; ; ; ; BOOT (boot record) ; ; loads at 0:7c00 ; ; located at start of partition (logical sector 0) ; ; ; ; RXDOSBIO.SYS ; ; loads initially at 70:0, relocated high ; ; boot record loads first three sectors (regardless of ; ; cluster size) ; ; initial part of rxdosbio.sys loads remainder of module ; ; high in low memory, then loads rxdos.sys ; ; ; ; RXDOS.SYS ; ; loaded by rxdosbio.sys ; ; ; ; RXDOSCMD.EXE ; ; ; ;...............................................................; ;'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''; ; Startup Code ; ;...............................................................; org 0000h public RxDOSBIOS_Start RxDOSBIOS_Start: jmp RxDOSBIOS_Initialize ;'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''; ; Block Device Info ; ;...............................................................; DISKBLOCK struc _dskNextPointer dd ? ; pointer to next _dskPhysDriveNumber db ? ; _dskDOSLogicalDiskUnit db ? ; _dskBPB db sizeBPB dup(?) ; _dskFATSystemStatus db ? ; _dskDevOpenCount dw ? ; _dskDeviceType db ? ; 22 _dskStatusFlag dw ? ; 23 _dskCylinders dw ? ; 25 _dskDefaultBPB db sizeBPB dup(?) ; 27 _dskPartitionBeginHead db ? ; begin head address _dskPartitionBeginSector db ? ; begin sector address _dskPartitionBeginCylinder db ? ; begin cylinder address _dskPartitionEndHead db ? ; end head address _dskPartitionEndSector db ? ; end sector address _dskPartitionEndCylinder db ? ; end cylinder address _dskCylinderAtLastOp db ? ; 46 _dskClockAtLastOp dd ? ; 47 _dskVolumeName db (sizeFILENAME + 1) dup(?) _dskSerialNumber dd ? ; 57 _dskFATSystemID db 8 dup(?) ; 5B _dskExtHiddenSectors dd ? ; extended hidden sectors DISKBLOCK ends sizeDISKBLOCK equ size DISKBLOCK ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ; Type Codes ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - DSKFILESYSTYPE_12Bits equ 00h DSKFILESYSTYPE_16Bits equ 40h DSKFILESYSTYPE_Invalid equ 80h DSKFILESYSTYPE_IsValid equ 40h ; only bits 7, 6 are assignable ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ; Form Codes ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - DSKFORMTYPES_40_9 equ 00h ; 40 cyls, <= 9 sect/track DSKFORMTYPES_80_15 equ 01h ; 80 cyls, 15 sect/track DSKFORMTYPES_80_9 equ 02h ; 80 cyls, 9 sect/track DSKFORMTYPES_HARDDISK equ 03h ; hard disk DSKFORMTYPES_FLOPPY_OTHER equ 07h ; other floppy disk types DSKFORMTYPES_80_36 equ 07h ; 80 cyls, 36 sect/track 1.44M ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ; Status Codes ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - IsNonRemovable equ 0001h ; non-removable media ChgLineSupportedbyBIOS equ 0002h ; change line supported BPBLocked equ 0004h ; BPB Locked status GoodTrackLayout equ 0008h ; if continuous sectors on track SharesPhysDevice equ 0010h ; if physical unit partitioned ActiveUnit equ 0020h ; if active unit DiskChangeDetected equ 0040h ; disk change detected DASD_SetRequired equ 0080h ; DASD_SetRequired VerifyWrite equ 0100h ; Verify Write RW_Disabled equ 0200h ; read/ write disabled ;'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''; ; Media Descriptor Table ; ;...............................................................; MEDIADESCRIPT struc _mdtSpecifyByte dw ? _mdtTimerTillMotorOff db ? _mdtBytesPerSector db ? ; 0 = 128, 1=256, 2=512, 3=1024 _mdtSectorsPerTrack db ? _mdtGapLengthinBytes db ? _mdtDataLengthinBytes db ? _mdtGapLengthForFormat db ? _mdtFillByteForFormat db ? _mdtHeadSettleTime db ? ; in ms _mdtMotorStartupTime db ? ; in 1/8 seconds MEDIADESCRIPT ends sizeMEDIADESCRIPT equ size MEDIADESCRIPT ;'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''; ; Data ; ;...............................................................; BootDrive: db 0 BootDrive_BPB: dw sizeCCBData ; __bsBytesPerSector db 1 ; __bsSectorsPerCluster dw 1 ; __bsResSectors db 2 ; __bsNumCopiesFAT dw 00E0h ; __bsMaxAllocRootDir dw 0960h ; __bsMaxSectors db 0f9h ; __bsMediaDescriptor dw 7 ; __bsSectorsPerFat dw 15 ; __bsSectorsPerTrack dw 2 ; __bsHeads dd 0 ; __bsHiddenSectors dd 0960h ; __bsHugeSectors RxDOSBIOS_INITBLOCK: db sizeSYSINIT dup(0) diskParameterTable: dd 0 ; disk parameter table _FATbuffer_SectorNumber: dd -1 ; allocated FAT sector _FATbuffer: dd 0 RootDirSector: dd 0 ; root directory sector ReservedBeforeDataSector: dd 0 ; first data sector RXDOSBIO_ClusterAddr: dw 0 ; cluster address of RxDOSBIO.SYS RXDOS_ClusterAddr: dw 0 ; cluster address of RxDOS.SYS _FloppyDrives: dw 0 ; # floppy drives _FixedDrives: dw 0 ; # fixed drives RxDOS_LoadSegment: dd 0 ; where RxDOS loaded ptr_StartBlockedDeviceTable: dd 0 ; ptr to Disk Parameter Blocks ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ; location of system entries in root directory ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - RXDOSBIO_SYS equ (0 * sizeDIRENTRY) RXDOS_SYS equ (1 * sizeDIRENTRY) ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ; messages ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - RXDOSBIO_MSGLoadingRxDOS: db "Starting RxDOS...", 0 RXDOSBIO_MSGErrorLoadingSystem: db 0Dh, 0Ah, "Error loading RxDOS. Please reboot. ", 0 IFDEF RxDOS_DEBUG RXDOSBIO_MSGDEBUG_CANTLOAD: db "Can't Load DEBUG Image", 0 ENDIF ;'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''; ; Load Program Using FAT ; ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -; ; ; ; Input: ; ; dx starting cluster address ; ; es:di buffer ; ; ; ; Output: ; ; cy error reading file ; ;...............................................................; _LoadProgram: Entry def _sectorsToRead ; sectors to read def _scanEndCluster, dx ; last cluster scanned def _currentCluster, dx ; cluster address of pgm /start def _relCluster ; rel cluster offset required ddef _buffer, es, di ; where to load xor dx, dx mov ax, word ptr [ _buffer. _pointer ][ bp ] div word ptr [ BootDrive_BPB. _bpbBytesPerSector ] div byte ptr [ BootDrive_BPB. _bpbSectorsPerCluster ] xor ah, ah storarg _relCluster, ax ; required rel cluster offset or ax, ax ; starts at first file cluster ? jz _LoadProgram_18 ; yes --> ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ; at start, we must position at rel cluster ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - _LoadProgram_14: mov ax, word ptr [ BootDrive ] mov dx, word ptr [ _currentCluster ][ bp ] call getNextCluster ; get next cluster jz _LoadProgram_Return ; exit if error --> mov word ptr [ _currentCluster ][ bp ], dx ; save cluster number dec word ptr [ _relCluster ][ bp ] ; scan more clusters ? jnz _LoadProgram_14 ; scan more --> ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ; optimize cluster read ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - _LoadProgram_18: mov ax, word ptr [ BootDrive ] mov dx, word ptr [ _currentCluster ][ bp ] call scanClusterMap mov word ptr [ _sectorsToRead ][ bp ], cx ; # sectors to sequentially read mov word ptr [ _scanEndCluster ][ bp ], dx ; last cluster scanned ; mov dl, byte ptr [ BootDrive_BPB. _bpbSectorsPerCluster ] ; sub dl, al ; sectors remaining ; sub word ptr [ _sectorsToRead ][ bp ], dx ; adjust sectors to read ; jnz _LoadProgram_26 ; keep reading if more required --> ; mov word ptr [ _sectorsToRead ][ bp ], 0001 ; else default to one sector ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ; get sector offset to read ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - _LoadProgram_26: xor dx, dx mov ax, word ptr [ _buffer. _pointer ][ bp ] div word ptr [ BootDrive_BPB. _bpbBytesPerSector ] div byte ptr [ BootDrive_BPB. _bpbSectorsPerCluster ] xor bh, bh mov bl, ah ; sector adjust for pointer mov ax, word ptr [ _currentCluster ][ bp ] dec ax dec ax xor cx, cx mov cl, byte ptr [ BootDrive_BPB. _bpbSectorsPerCluster ] mul cx ; compute sector add ax, word ptr [ ReservedBeforeDataSector. _low ] adc dx, word ptr [ ReservedBeforeDataSector. _high ] add ax, bx ; add sector adjust adc dx, 0000 ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ; read buffer ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - mov cx, dx mov dx, ax ; sector address mov al, byte ptr [ BootDrive ] getdarg es, di, _buffer getarg bx, _sectorsToRead call ReadBuffer ; do read jc _LoadProgram_Abrupt ; if error --> mov ax, word ptr [ _sectorsToRead ][ bp ] mul word ptr [ BootDrive_BPB. _bpbBytesPerSector ] add word ptr [ _buffer. _pointer ][ bp ], ax getarg dx, _scanEndCluster ; last cluster scanned storarg _currentCluster, dx ; cluster address of pgm /start cmp dx, -1 ; was last read to end of file ? jnz _LoadProgram_18 ; no, keep reading --> ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ; return ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - _LoadProgram_Return: mov cx, word ptr [ _buffer. _pointer ][ bp ] or cx, cx ; if ok return _LoadProgram_Abrupt: Return ;'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''; ; Read FAT Buffer ; ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -; ; ; ; Input: ; ; cx:dx sector to read ; ;...............................................................; readFATBuffer: les di, dword ptr [ _FATbuffer ] cmp word ptr [ _FATbuffer_SectorNumber. _low ], dx jnz readFATBuffer_08 cmp word ptr [ _FATbuffer_SectorNumber. _high ], cx jz readFATBuffer_12 readFATBuffer_08: mov bx, 0001 mov al, byte ptr [ BootDrive ] mov word ptr [ _FATbuffer_SectorNumber. _high ], cx mov word ptr [ _FATbuffer_SectorNumber. _low ], dx call readBuffer readFATBuffer_12: ret ;'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''; ; Read Buffer ; ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -; ; ; ; Input: ; ; ax drive ; ; bx buffers to read ; ; cx:dx logical sector to read ; ; es:di buffer address ; ;...............................................................; readBuffer: Entry ddef _bufferPtr, es, di ddef _sector, cx, dx ; def _readSector ; def _readHead ; def _readTrack def _drive, ax def _buffers, bx def _retries SaveRegisters bp, dx, ax, cx readBuffer_08: mov word ptr [ _retries ][ bp ], 3 readBuffer_10: getdarg dx, ax, _sector add ax, word ptr [ BootDrive_BPB. _bpbHiddenSectors. _low ] adc dx, word ptr [ BootDrive_BPB. _bpbHiddenSectors. _high ] div word ptr [ BootDrive_BPB. _bpbSectorsPerTrack ] inc dl mov cl, dl ; _readSector xor dx, dx div word ptr [ BootDrive_BPB. _bpbHeads ] ; mov word ptr [ _readTrack ][ bp ], ax ; dont need to save track ; mov byte ptr [ _readHead ][ bp ], dl ; don't need to save heads mov dh, dl ; head shl ah, 1 ; high order two bits of track shl ah, 1 ; ... moved to top end of reg shl ah, 1 shl ah, 1 shl ah, 1 shl ah, 1 or cl, ah ; or with sector mov ch, al ; remainder of track to ch mov al, byte ptr [ _buffers ][ bp ] ; plus buffers to read mov ah, al ; buffers add ah, cl ; starting sector sub ah, byte ptr [ BootDrive_BPB. _bpbSectorsPerTrack ] jle readBuffer_12 ; no, ok to read --> sub al, ah ; safe number of buffers to read inc ax readBuffer_12: push ax ; # buffers requested mov ah, 02h ; read command type mov dl, byte ptr [ _drive ][ bp ] getdarg es, bx, _bufferPtr ; NormalizeBuffer es, bx int 13h pop ax ; # buffers requested jc readBuffer_26 ; if error --> xor ah, ah xor cx, cx mov bx, ax mul word ptr [ BootDrive_BPB. _bpbBytesPerSector ] add word ptr [ _bufferPtr. _pointer ][ bp ], ax add word ptr [ _sector. _low ][ bp ], bx adc word ptr [ _sector. _high ][ bp ], cx sub byte ptr [ _buffers ][ bp ], bl ; buffers remaining after this read jg readBuffer_08 ; if more to read jmp short readBuffer_28 ; exit --> readBuffer_26: xor ax, ax mov dl, byte ptr [ _drive ][ bp ] int 13h ; if error, attempt reset dec word ptr [ _retries ][ bp ] jnz readBuffer_10 stc ; make sure exit with error flag readBuffer_28: RestoreRegisters cx, ax, dx, bp Return ;'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''; ; Get Next Cluster ; ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -; ; ; ; Input: ; ; ax drive ; ; dx current cluster ; ; ; ; Output: ; ; dx next cluster ; ; zr if end of cluster chain. ; ;...............................................................; getNextCluster: Entry def _drive, ax def _cluster, dx def _MaxClusters saveRegisters es, di, si, cx, bx, ax ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ; determine whether its 12 or 16 bit FAT entries ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - xor cx, cx mov cl, byte ptr [ BootDrive_BPB. _bpbSectorsPerCluster ] mov dx, word ptr [ BootDrive_BPB. _bpbHugeSectors. _high ] mov ax, word ptr [ BootDrive_BPB. _bpbHugeSectors. _low ] div cx storarg _MaxClusters, ax mov dx, word ptr [ BootDrive_BPB. _bpbHugeSectors. _high ] mov ax, word ptr [ BootDrive_BPB. _bpbHugeSectors. _low ] mov dx, -1 ; presume end if error mov ax, word ptr [ _cluster ][ bp ] ; get cluster # or ax, ax ; invalid number jz getNextCluster_Return ; exit --> cmp ax, word ptr [ _MaxClusters ][ bp ] jnc getNextCluster_Return ; if valid cluster # --> getNextCluster_08: xor dx, dx test word ptr [ _MaxClusters ][ bp ], 0F000h jnz getNextCluster_16Bits ; if 16 --> ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ; 12 bit FAT entries ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - getNextCluster_12Bits: mov ax, word ptr [ _drive ][ bp ] ; get drive mov dx, word ptr [ _cluster ][ bp ] ; and cluster call _get_12Bit_ClusterValue jmp short getNextCluster_Return ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ; 16 bit FAT entries ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - getNextCluster_16Bits: mov cx, word ptr [ BootDrive_BPB. _bpbBytesPerSector ] shr cx, 1 div cx ; FAT sector/ Offset ; ax will contain FAT sector ; dx will contain byte offset into FAT sector add dx, dx ; make word offset push dx xor cx, cx mov dx, word ptr [ BootDrive_BPB. _bpbResSectors ] ; where is first FAT table ? add dx, ax ; add offset required mov ax, word ptr [ _drive ][ bp ] ; get drive call ReadFATBuffer ; read FAT Table pop bx ; word offset into FAT table mov dx, word ptr es:[ bx + di ] ; get FAT word mov ax, dx and ax, 0FFF8h ; FAT value, 12 bit entries. cmp ax, 0FFF8h ; end of chain ? jnz getNextCluster_Return ; no --> mov dx, -1 ; if end, set end value ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ; return ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - getNextCluster_Return: restoreRegisters ax, bx, cx, si, di, es cmp dx, -1 ; set if end of chain Return ;'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''; ; Scan Ahead Cluster Map ; ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -; ; ; ; Input: ; ; ax drive ; ; dx current cluster ; ; ; ; Output: ; ; cx # sectors to sequentially read ; ; dx last cluster value ; ;...............................................................; scanClusterMap: Entry def _drive, ax def _cluster, dx def _nextCluster def _clusterCount, 0000 scanClusterMap_12: inc word ptr [ _clusterCount ][ bp ] ; cluster count mov cx, dx call getNextCluster ; get next cluster cmp dx, -1 ; end ? jz scanClusterMap_22 ; yes --> sub cx, dx ; sequential clusters are ... cmp cx, -1 ; ... identified by a -1 offset jz scanClusterMap_12 ; if still sequential --> scanClusterMap_22: mov ax, word ptr [ _clusterCount ][ bp ] ; # sequential clusters mul byte ptr [ BootDrive_BPB. _bpbSectorsPerCluster ] mov cx, ax ; # sectors to sequentially read Return ;'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''; ; Get 12Bit FAT Table Value ; ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -; ; ; ; Input: ; ; ax drive ; ; dx current cluster ; ; ; ; Output: ; ; dx value at cluster (next cluster) ; ; zr if end of cluster chain. ; ;...............................................................; _get_12Bit_ClusterValue: Entry def _drive, ax def _cluster, dx def _sectorsize ddef _sector mov ax, dx add ax, ax add ax, dx ; nibble address xor dx, dx mov cx, word ptr [ BootDrive_BPB. _bpbBytesPerSector ] mov word ptr [ _sectorsize ][ bp ], cx dec word ptr [ _sectorsize ][ bp ] shl cx, 1 ; nibbles / sector div cx ; sector to read ; ax will contain sector ; dx will contain nibble offset shr dx, 1 ; word offset push dx ; xor cx, cx ; 32 bit address mov dx, ax add dx, word ptr [ BootDrive_BPB. _bpbResSectors ] ; where is first FAT table ? stordarg _sector, cx, dx ; 32 bit sector address mov ax, word ptr [ _drive ][ bp ] ; get drive call ReadFATBuffer ; read FAT Table pop bx ; word offset into FAT table mov dx, word ptr es:[ bx + di ] ; get FAT word cmp bx, word ptr [ _sectorsize ][ bp ] ; at sector size -1 boundry ? jnz _get_12Bit_ClusterValue_12 ; no, ok to return as is --> push dx ; else save what we have getdarg cx, dx, _sector ; read next cluster sector add dx, 0001 ; incr by one adc cx, 0000 mov ax, word ptr [ _drive ][ bp ] ; get drive call ReadFATBuffer ; read FAT Table pop dx mov dh, byte ptr es:[ di ] ; get FAT word at start of buffer _get_12Bit_ClusterValue_12: test word ptr [ _cluster ][ bp ], 1 ; is cluster Odd ? jz _get_12Bit_ClusterValue_14 ; no, just take value --> shr dx, 1 shr dx, 1 shr dx, 1 shr dx, 1 _get_12Bit_ClusterValue_14: and dx, 0FFFh ; 12 bit mask mov ax, dx and ax, 00FF8h ; FAT value, 12 bit entries. cmp ax, 00FF8h ; end of chain ? jnz _get_12Bit_ClusterValue_16 ; no --> mov dx, -1 ; if end, set end value _get_12Bit_ClusterValue_16: Return ;'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''; ; Error Display ; ;...............................................................; RxDOSBIOS_Error: mov si, offset RXDOSBIO_MSGErrorLoadingSystem call _DisplayMsg RxDOSBIOS_Error_04: xor ax, ax int 16h jmp RxDOSBIOS_Error_04 ;'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''; ; Display Message ; ;...............................................................; _DisplayMsg: push cs pop ds _DisplayMsg_02: lodsb ; get character (ds:si) or al, al ; null terminator ? jnz _DisplayMsg_06 ; not yet --> ret _DisplayMsg_06: push si mov ah, 0Eh mov bx, 0007h int 10h pop si jmp _DisplayMsg_02 ;'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''; ; Init Interrupt Vectors ; ;...............................................................; InitInterruptVectors: mov word ptr es:[ _segment ][ bx ], cs mov word ptr es:[ _pointer ][ bx ], offset IntReturn add bx, 4 loop InitInterruptVectors ret ;'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''; ; Initialize ; ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -; ; ; ; The boot loader loader transfers control to here with the ; ; following arguments: ; ; ; ; CH media descriptor byte ; ; DL unit address of startup drive ; ; AX:BX sector address of root directory ; ; DS:SI BIOS parameter table ; ; ; ; int 1E address contains a pointer to the current drive DISK ; ; PARAMETER Table. ; ; ; ;...............................................................; RxDOSBIOS_Initialize: cli cld mov word ptr cs:[ diskParameterTable. _pointer ], si mov word ptr cs:[ diskParameterTable. _segment ], ds mov byte ptr cs:[ BootDrive ], dl ; physical drive (80, ... ) mov ax, cs mov ds, ax ; DS: mov es, ax ; ES: mov ss, ax ; SS: mov sp, offset RxDOSBIOS_LastAddress + 1024 ; temporary stack sti ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ; copy BPB from boot record (at 0:7C0Bh) ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - push ds xor ax, ax mov ds, ax ; disk boot table mov si, 7C0Bh ; at 0000:7C0B mov di, offset BootDrive_BPB mov cx, sizeBPB rep movsb ; copy BPB ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ; get cluster address of RXDOSBIO.SYS and RXDOS.SYS ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - pop ds xor ax, ax mov es, ax ; ES: mov si, 500h ; where root directory is located mov ax, word ptr es:[ RXDOSBIO_SYS. deStartCluster ][ si ] mov dx, word ptr es:[ RXDOS_SYS. deStartCluster ][ si ] mov word ptr [ RXDOSBIO_ClusterAddr ], ax mov word ptr [ RXDOS_ClusterAddr ], dx ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ; relocate disk parameter table to safe address ( at, surprisingly, 0:522 ) ; we move it here to maintain some strange compatability with the other DOS. ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - cli mov di, 522h ; destination address (0:522) mov word ptr es:[ 1Eh * 4 ][ _segment ], es mov word ptr es:[ 1Eh * 4 ][ _pointer ], di lds si, dword ptr cs:[ diskParameterTable ] ; where to copy table mov cx, 11 rep movsb sti mov bx, 522H + _mdtHeadSettleTime mov byte ptr es:[ bx ], 2 ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ; relocate this loader up to the high end of lower memory ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - mov ax, cs mov ds, ax mov es, ax int 12h ; get memory configuration mov word ptr [ RxDOSBIOS_INITBLOCK. initMemParagraphs ], ax shl ax, 1 shl ax, 1 shl ax, 1 shl ax, 1 shl ax, 1 shl ax, 1 ; shl ax, 6 sub ax, 64 * (1024 / sizePARAGRAPH) ; subtract 64k in segment form mov word ptr [ _FATbuffer. _segment ], ax ; address of FAT buffer ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ; switch stacks so it doesn't get clobbered during load ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - cli mov ss, ax ; new stack mov sp, 0FE00h nop sti ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ; initialize and load ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - xor ax, ax mov al, byte ptr [ BootDrive_BPB. _bpbNumCopiesFAT ] mul word ptr [ BootDrive_BPB. _bpbSectorsPerFat ] add ax, word ptr [ BootDrive_BPB. _bpbResSectors ] adc dx, 0000 mov word ptr [ RootDirSector. _low ], ax mov word ptr [ RootDirSector. _high ], dx ; read first sector of Root Directory mov cx, word ptr [ BootDrive_BPB. _bpbMaxAllocRootDir ] shr cx, 1 shr cx, 1 shr cx, 1 shr cx, 1 add ax, cx adc dx, 0000 mov word ptr [ ReservedBeforeDataSector. _low ], ax mov word ptr [ ReservedBeforeDataSector. _high ], dx ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ; Reset Interrupts ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - mov al, 20h out 20h, al ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ; Display startup banner ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - mov si, offset RXDOSBIO_MSGLoadingRxDOS call _DisplayMsg ; Loading RxDOS ... IFDEF RxDOS_DEBUG mov si, offset RXDOSBIO_MSGDEBUG_CANTLOAD call _DisplayMsg ; Can't Load Debug Image RxDOSBIOS_InitHalt: jmp RxDOSBIOS_InitHalt ENDIF ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ; load the remainder of rxdosbio.sys and rxdos.sys ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - mov di, 600h ; reload starts at 600h mov dx, word ptr [ RXDOSBIO_ClusterAddr ] call _LoadProgram ; Load RxDOSBIO ifc RxDOSBIOS_Error ;'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''; ; Load Protection ; ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -; ; ; ; Everything above this line must reside in the first 600 hex ; ; bytes of the file. This is the minimal portion loaded by the ; ; bootstarp loader. ; ; ; ; The code below causes an error message in compile if the ; ; file size at this location will exceed 600 hex bytes. ; ;...............................................................; IF1 IF ($ GE 600h) error "RxDOSBIO minimal section exceeds 600h (3 sectors) bytes." ENDIF ENDIF ;'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''; ; Hardware Evaluation and Startup ; ;...............................................................; RxDOSBIOS_EvaluateHardware: mov dl, byte ptr BootDrive ; physical drive mov byte ptr [ RxDOSBIOS_INITBLOCK. initBootDrive ], dl mov word ptr [ RxDOSBIOS_INITBLOCK. initDeviceChain. _segment ], cs mov word ptr [ RxDOSBIOS_INITBLOCK. initDeviceChain. _pointer ], offset CON ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ; Determine the amount of actual memory ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - int 12h ; get memory size mov word ptr [ RxDOSBIOS_INITBLOCK. initMemParagraphs ], ax ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ; Determine number of floppy drives ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - int 11h ; read hardware configuration mov word ptr [ _floppyDrives ], 0000 ; number of floppy disks test ax, 1 ; floppy disks listed ? jz RxDOSBIOS_EvalHardware_08 ; if no --> shr ax, 1 ; floppy bit shr ax, 1 ; math coprocessor shr ax, 1 ; memory (xt only) shr ax, 1 ; shr ax, 1 ; video mode bits shr ax, 1 ; and ax, 0003h inc ax jmp short RxDOSBIOS_EvalHardware_12 RxDOSBIOS_EvalHardware_08: mov ah, 8 ; read parameters mov dl, 0 ; unit 0 int 13h mov al, dl mov ah, 0 ; number of drives (if any ) jnc RxDOSBIOS_EvalHardware_12 ; if drives reported --> xor ax, ax RxDOSBIOS_EvalHardware_12: mov word ptr [ _floppyDrives ], ax ; number of floppy disks ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ; Determine number of hard disk drives ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - xor bx, bx mov ax, 40h mov es, ax mov al, byte ptr es:[ _BIOS_NumFixedDrives ][ bx ] mov word ptr [ _fixedDrives ], ax ; number of fixed drives ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ; determine (manufacture) floppy drives ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - mov ax, word ptr [ _fixedDrives ] ; get number of fixed drives or ax, ax ; if no hard disk, total is fine jnz RxDOSBIOS_EvalHardware_20 ; make sure we add 2 floppy drives --> cmp word ptr [ _floppyDrives ], 0000 ; number of floppy disks jz RxDOSBIOS_EvalHardware_22 ; if diskless system --> RxDOSBIOS_EvalHardware_20: mov word ptr [ _floppyDrives ], 2 ; if hard disk or one floppy ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ; Setup remainder of INIT Block ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - RxDOSBIOS_EvalHardware_22: mov word ptr [ RxDOSBIOS_INITBLOCK. initRelocHighBegAddress. _segment ], cs mov word ptr [ RxDOSBIOS_INITBLOCK. initRelocHighBegAddress. _pointer ], offset RxDOSBIOS_Start mov word ptr [ RxDOSBIOS_INITBLOCK. initRelocHighSize ], RxDOSBIOS_LastAddress - RxDOSBIOS_Start mov word ptr [ RxDOSBIOS_INITBLOCK. initRelocHighNotify ], -1 mov word ptr [ RxDOSBIOS_INITBLOCK. initRelocLowBegAddress. _segment ], 0000 mov word ptr [ RxDOSBIOS_INITBLOCK. initRelocLowBegAddress. _pointer ], 0000 mov word ptr [ RxDOSBIOS_INITBLOCK. initRelocLowSize ], 0000 mov word ptr [ RxDOSBIOS_INITBLOCK. initRelocHighNotify ], -1 ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ; fix-up device driver chain ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - mov si, offset con RxDOSBIOS_InitDeviceChain: mov word ptr _segment [ si ], cs mov si, word ptr _pointer [ si ] cmp si, -1 jnz RxDOSBIOS_InitDeviceChain ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ; Set Interrupt Vectors ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - xor ax, ax mov es, ax mov dx, word ptr es:[ 0h * 4 ][ _segment ] ; divide by zero int mov ax, word ptr es:[ 0h * 4 ][ _pointer ] mov word ptr cs:[ DivideByZero. _segment ], dx mov word ptr cs:[ DivideByZero. _pointer ], ax mov word ptr es:[ 0h * 4 ][ _segment ], cs mov word ptr es:[ 0h * 4 ][ _pointer ], offset Interrupt_0 mov word ptr es:[ _segment ][ 29h * 4 ], cs mov word ptr es:[ _pointer ][ 29h * 4 ], offset Interrupt_29 mov cx, 6 mov bx, 0001 * 4 ; int 01h - int 07h call InitInterruptVectors mov bx, 33h * 4 ; int 33h mov word ptr es:[ _segment ][ bx ], cs mov word ptr es:[ _pointer ][ bx ], offset IntReturn ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ; Initialize Disk Parameter Tables ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - setDS cs mov cx, word ptr [ _fixedDrives ] ; number of fixed drives mov dx, word ptr [ _floppyDrives ] ; number of floppy disks call initDiskParameterBlocks ; returns actual # devices mov word ptr [ RxDOSBIOS_INITBLOCK. initTotalDrives ], cx mov byte ptr [ block. devUnits ], cl ; block device header ;'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''; ; Load remainder of RxDOS ; ;...............................................................; mov ax, sizeDISKBLOCK ; number of block devices mul cx ; size required by table add ax, offset RxDOSBIOS_LastAddress + (sizeParagraph - 1) shr ax, 1 shr ax, 1 shr ax, 1 shr ax, 1 ; paragraphs size mov dx, cs ; current segment add dx, ax mov es, dx ; seg address to load next module. mov word ptr [ RxDOSBIOS_INITBLOCK. initLowMemSegment ], es mov word ptr [ RxDOS_LoadSegment. _segment ], es xor di, di mov dx, word ptr [ RXDOS_ClusterAddr ] call _LoadProgram ; Load RxDOS ifc RxDOSBIOS_Error add cx, (PARAGRAPH-1) ; (rounded up) shr cx, 1 shr cx, 1 shr cx, 1 shr cx, 1 ; paragraphs read add word ptr [ RxDOSBIOS_INITBLOCK. initLowMemSegment ], cx push cs pop es mov dl, byte ptr BootDrive ; physical drive mov di, offset RxDOSBIOS_INITBLOCK JMP dword ptr cs:[ RxDOS_LoadSegment ] ;'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''; ; Strategy Argument ; ;...............................................................; Strategy dd 0 ;'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''; ; Con Definition ; ;...............................................................; con dd clock dw ( DEV_CHAR + DEV_STDINPUT + DEV_STDOUTPUT + DEV_FASTCHARIO ) dw _DevStrategy dw con_interrupt db 'CON ' dw con_servicetable, 0 con_servicetable db (maxcon - con_servicetable - 1) / 2 dw _NoAction ; = 0, Init dw _NoAction ; = 1, Media Check dw _NoAction ; = 2, Build BPB dw _NoAction ; = 3, IOCTL Read dw ConRead ; = 4, Read dw ConNonDestrRead ; = 5, Nondestructive Read dw ConStatus ; = 6, Input Status dw ConInputFlush ; = 7, Input Flush dw ConWrite ; = 8, Write dw ConWrite ; = 9, Write With Verify dw _NoAction ; =10, Output Status maxcon = $ Con_LookAhead dw 0 Con_ScanCode db 0 Con_TabPosition dw 0 ;'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''; ; Clock Device Definitions ; ;...............................................................; clock dd prn dw ( DEV_CHAR + DEV_CLOCK ) dw _DevStrategy dw clock_interrupt db 'CLOCK$ ' dw clock_servicetable, 0 clock_servicetable db (maxclock - clock_servicetable - 1) / 2 dw _NoAction ; = 0, Init dw _NoAction ; = 1, Media Check dw _NoAction ; = 2, Build BPB dw _IllegalFunction ; = 3, IOCTL Read dw ClockRead ; = 4, Read dw ClockRead ; = 5, Nondestructive Read dw _NoAction ; = 6, Input Status dw _NoAction ; = 7, Input Flush dw ClockWrite ; = 8, Write dw ClockWrite ; = 9, Write With Verify dw _NoAction ; =10, Output Status maxclock = $ ;'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''; ; Print, Lpt1, ... Definitions ; ;...............................................................; prn dd lpt1 dw ( DEV_CHAR + DEV_OUTPUTTILLBUSY ) dw _DevStrategy dw prn_interrupt db 'PRN ' dw prn_servicetable, 0 lpt1 dd lpt2 dw ( DEV_CHAR + DEV_OUTPUTTILLBUSY ) dw _DevStrategy dw lpt1_interrupt db 'LPT1 ' dw prn_servicetable, 0 lpt2 dd lpt3 dw ( DEV_CHAR + DEV_OUTPUTTILLBUSY ) dw _DevStrategy dw lpt2_interrupt db 'LPT2 ' dw prn_servicetable, 2 lpt3 dd aux dw ( DEV_CHAR + DEV_OUTPUTTILLBUSY ) dw _DevStrategy dw lpt3_interrupt db 'LPT3 ' dw prn_servicetable, 3 prn_servicetable db (maxprn - prn_servicetable - 1) / 2 dw _NoAction ; = 0, Init dw _NoAction ; = 1, Media Check dw _NoAction ; = 2, Build BPB dw _NoAction ; = 3, IOCTL Read dw _NoAction ; = 4, Read dw _NoAction ; = 5, Nondestructive Read dw _NoAction ; = 6, Input Status dw _NoAction ; = 7, Input Flush dw PrnWrite ; = 8, Write dw PrnWrite ; = 9, Write With Verify dw PrnStatus ; =10, Output Status dw _NoAction ; =11, Output Flush dw _NoAction ; =12, IOCTL Write dw _NoAction ; =13, Open Device dw _NoAction ; =14, Close Device dw _NoAction ; =15, Removable Media dw _NoAction ; =16, Output Until Busy dw _NoAction ; =17, unused dw _NoAction ; =18, unused dw _NoAction ; =19, Generic IOCTL dw _NoAction ; =20, unused dw _NoAction ; =21, unused dw _NoAction ; =22, unused dw _NoAction ; =23, Get Logical Device dw _NoAction ; =24, Set Logical Device dw _NoAction ; =25, IOCTL query maxprn = $ ;'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''; ; Aux, Com1, ... Definitions ; ;...............................................................; aux dd com1 dw ( DEV_CHAR ) dw _DevStrategy dw aux_interrupt db 'AUX ' dw aux_servicetable, 0 com1 dd com2 dw ( DEV_CHAR ) dw _DevStrategy dw com1_interrupt db 'COM1 ' dw aux_servicetable, 0 com2 dd block dw ( DEV_CHAR ) dw _DevStrategy dw com2_interrupt db 'COM2 ' dw aux_servicetable, 1 aux_servicetable db (maxaux - aux_servicetable - 1) / 2 dw _NoAction ; = 0, Init dw _NoAction ; = 1, Media Check dw _NoAction ; = 2, Build BPB dw _NoAction ; = 3, IOCTL Read dw AuxRead ; = 4, Read dw AuxNonDestrRead ; = 5, Nondestructive Read dw _NoAction ; = 6, Input Status dw AuxInputFlush ; = 7, Input Flush dw AuxWrite ; = 8, Write dw AuxWrite ; = 9, Write With Verify dw AuxOutputStatus ; =10, Output Status maxaux = $ ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ; Comm LookAhead Buffer ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Comm_LookAhead db 4 dup(0) ; com1, com2, com3, ... ;'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''; ; Block Device ; ;...............................................................; block dw -1, 0 dw ( DEV_REMOVABLEMEDIA ) dw _DevStrategy dw block_interrupt db 03, 7 dup (0) ; pre-initialized to three devs dw block_servicetable, 0 block_servicetable db (maxblock - block_servicetable - 1) / 2 dw _hdInit ; = 0, Init dw _hdMediaCheck ; = 1, Media Check dw _hdBuildBPB ; = 2, Build BPB dw _hdIOCTLRead ; = 3, IOCTL Read dw _hdRead ; = 4, Read dw _NoAction ; = 5, Nondestructive Read dw _NoAction ; = 6, Input Status dw _NoAction ; = 7, Input Flush dw _hdWrite ; = 8, Write dw _hdWriteWithVerify ; = 9, Write With Verify dw _NoAction ; =10, Output Status dw _NoAction ; =11, Output Flush dw _hdIOCTLWrite ; =12, IOCTL Write dw _hdOpenDevice ; =13, Open Device dw _hdCloseDevice ; =14, Close Device dw _hdRemovableMedia ; =15, Removable Media dw _NoAction ; =16, Output Until Busy dw _NoAction ; =17, unused dw _NoAction ; =18, unused dw _hdGenericIOCTL ; =19, Generic IOCTL dw _NoAction ; =20, unused dw _NoAction ; =21, unused dw _NoAction ; =22, unused dw _hdGetLogicalDevice ; =23, Get Logical Device dw _hdSetLogicalDevice ; =24, Set Logical Device dw _hdIOCTLQuery ; =25, IOCTL query maxblock = $ ;'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''; ; Device Strategy ; ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -; ; ; ; Input: ; ; ES:BX request header ; ;...............................................................; _DevStrategy proc far ; cli mov word ptr cs:[ Strategy. _segment ], es mov word ptr cs:[ Strategy. _pointer ], bx ret _DevStrategy endp ;'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''; ; Device Interrupt ; ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -; ; ; ; Input: ; ; ES:BX request header ; ; ; ; on stack pointer to strategy table ; ; on stack logical unit ; ; ; ; This appears to be a function, but is some common code that ; ; *most* but not necessarily all functions jump to. IT MUST ; ; MAKE A FAR RETURN ON EXIT. ; ; ; ;...............................................................; _DevInterrupt: Entry rArg _LogicalUnit, 4 rArg _StrategyTable, 2 ; offset to items in stack ddef _RequestBlock def _ServiceAddr cld SaveAllRegisters lds bx, dword ptr cs:[ Strategy ] ; compliant strategy call stordarg _RequestBlock, ds, bx ; see text for compliance issues sti mov al, byte ptr [ rhFunction ][ bx ] cbw add ax, ax inc ax ; offset past table entry count mov si, word ptr [ _StrategyTable ][ bp ] add si, ax mov ax, word ptr cs:[ si ] mov word ptr [ _ServiceAddr ][ bp ], ax push bp ; device or BIOS might change bp mov ah, byte ptr [ rhMedia ][ bx ] mov al, byte ptr [ rhUnit ][ bx ] mov cx, word ptr [ rwrBytesReq ][ bx ] mov dx, word ptr [ _LogicalUnit ][ bp ] ; passed to function mov word ptr [ rhStatus ][ bx ], 0000 ;- - - - - - - - - - - - - - - - - - - - - - - ; es: di pointer to buffer, if any ; ds: bx pointer to packet ;- - - - - - - - - - - - - - - - - - - - - - - les di, dword ptr [ rwrBuffer ][ bx ] call word ptr [ _ServiceAddr ][ bp ] pop bp ; device or BIOS may have changed bp lds bx, dword ptr [ _RequestBlock ][ bp ] or word ptr [ rhStatus ][ bx ], (OP_DONE) RestoreAllRegisters ; restore all other registers mov sp, bp pop bp add sp, 4 ; sum of arg references retf ;'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''; ; No Action ; ;...............................................................; _NoAction: mov word ptr [ rwrStatus ][ bx ], ( OP_DONE ) ret ;'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''; ; Illegal Function ; ;...............................................................; _IllegalFunction: mov word ptr [ rwrStatus ][ bx ], ( OP_EXITERROR + devErrUnknownCommand ) mov word ptr [ rwrBytesReq ][ bx ], 0000 ret ;'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''; ; Strategies ; ;...............................................................; clock_interrupt: push word ptr cs:[ CLOCK. devLogicalUnit ] push word ptr cs:[ CLOCK. devTablePtr ] jmp _DevInterrupt prn_interrupt: push word ptr cs:[ PRN. devLogicalUnit ] push word ptr cs:[ PRN. devTablePtr ] jmp _DevInterrupt lpt1_interrupt: push word ptr cs:[ LPT1. devLogicalUnit ] push word ptr cs:[ LPT1. devTablePtr ] jmp _DevInterrupt lpt2_interrupt: push word ptr cs:[ LPT2. devLogicalUnit ] push word ptr cs:[ LPT2. devTablePtr ] jmp _DevInterrupt lpt3_interrupt: push word ptr cs:[ LPT3. devLogicalUnit ] push word ptr cs:[ LPT3. devTablePtr ] jmp _DevInterrupt aux_interrupt: push word ptr cs:[ AUX. devLogicalUnit ] push word ptr cs:[ AUX. devTablePtr ] jmp _DevInterrupt com1_interrupt: push word ptr cs:[ COM1. devLogicalUnit ] push word ptr cs:[ COM1. devTablePtr ] jmp _DevInterrupt com2_interrupt: push word ptr cs:[ COM2. devLogicalUnit ] push word ptr cs:[ COM2. devTablePtr ] jmp _DevInterrupt con_interrupt: push word ptr cs:[ CON. devLogicalUnit ] push word ptr cs:[ CON. devTablePtr ] jmp _DevInterrupt block_interrupt: push word ptr cs:[ BLOCK. devLogicalUnit ] push word ptr cs:[ BLOCK. devTablePtr ] jmp _DevInterrupt ;'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''; ; Clock Read ; ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -; ; ; ; On Input: ; ; ; ; ds:bx points to request header ; ; es:di points to CLOCKDATA buffer ; ; cx characters to transfer ; ; dl logical device ; ; ; ;...............................................................; ClockRead: Entry ddef _packet, ds, bx ddef _buffer ddef _ticks def _seconds def _minutes def _hours def _century def _year def _month def _day mov ax, word ptr [ rwrBuffer. _pointer ][ bx ] ; packet mov dx, word ptr [ rwrBuffer. _segment ][ bx ] stordarg _buffer, dx, ax xor ax, ax ; read real time clock Exint 1Ah ; cx/dx contains time of day or al, al ; over 24 hours ? jz clockRead_12 ; no --> inc word ptr [ _day ][ bp ] ; increment day. clockRead_12: stordarg _ticks, cx, dx ; save clock ticks mov ax, 0400h ; see if extended BIOS support mov cx, -1 ; these will change if extended support mov dx, -1 ; ch = BCD century / cl = BCD year Exint 1Ah ; dh = BCD month / dl = BCD day cmp cx, -1 ; was date returned ? jz clockRead_14 ; no, we'll skip save --> push dx ; month/ day push cx ; century/ year mov al, ch ; century call ConvBCDToBin mov word ptr [ _century ][ bp ], ax pop ax ; year call ConvBCDToBin mov word ptr [ _year ][ bp ], ax pop dx push dx mov al, dh ; month call ConvBCDToBin mov word ptr [ _month ][ bp ], ax pop ax ; day call ConvBCDToBin mov word ptr [ _day ][ bp ], ax ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ; compute days since 1980 ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - mov ax, 100 mul word ptr [ _century ][ bp ] ; century add ax, word ptr [ _year ][ bp ] mov cx, ax ; 1994, ... 2004, ... mov dh, byte ptr [ _month ][ bp ] mov dl, byte ptr [ _day ][ bp ] getdarg es, di, _buffer mov byte ptr es:[ cl_day ][ di ], dl mov byte ptr es:[ cl_month ][ di ], dh mov word ptr es:[ cl_year ][ di ], cx call getDaysSince1980 getdarg es, di, _buffer mov word ptr es:[ cl_daysSince1980 ][ di ], ax ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ; compute time from ticks ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - clockRead_14: mov ax, 0200h ; see if extended BIOS support mov cx, -1 ; these will change if extended support mov dx, -1 ; ch = BCD hours / cl = BCD minutes Exint 1Ah ; dh = BCD seconds / dl = daylight savings time getdarg es, di, _buffer getdarg dx, ax, _ticks ; get clock ticks back mov cx, 10 call _mul32 ; ticks times 10 mov cx, 182 ; clock ticks per second call _div32 push ax push dx xor dx, dx mov ax, 549 call _mul32 ; each tick is .0549 of a second mov cx, 100 call _div32 ; hundreds mov byte ptr es:[ cl_hseconds ][ di ], cl pop dx pop ax mov cx, 60 ; seconds per minute call _div32 storarg _seconds, cx mov byte ptr es:[ cl_seconds ][ di ], cl mov cx, 60 ; minutes per hour call _div32 storarg _minutes, cx storarg _hours, ax mov byte ptr es:[ cl_minutes ][ di ], cl mov byte ptr es:[ cl_hours ][ di ], al ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ; Convert to BCD form ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - call convToBCD ; hours (already in AX) to BCD mov ch, al ; hours getarg ax, _minutes call convToBCD ; minutes mov cl, al ; minutes getarg ax, _seconds call convToBCD ; seconds mov dh, al ; seconds mov dl, 0 ; daylight savings time (don't know) ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ; Day of Week (not computed) ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - mov word ptr [ rwrBytesReq ][ bx ], size CLOCKDATA Return ;'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''; ; Clock Write ; ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -; ; ; ; On Input: ; ; ; ; ds:bx points to request header ; ; es:di points to CLOCKDATA buffer ; ; cx characters to transfer ; ; dl logical device ; ; ; ;...............................................................; ClockWrite: Entry ddef _packet, ds, bx ddef _buffer, es, di def _yearBCD def _monthBCD def _dayBCD ddef _ticks mov di, word ptr [ rwrBuffer. _pointer ][ bx ] ; packet mov es, word ptr [ rwrBuffer. _segment ][ bx ] stordarg _buffer, es, di mov al, byte ptr es:[ cl_day ][ di ] call convToBCD ; day storarg _dayBCD, ax mov al, byte ptr es:[ cl_month ][ di ] call convToBCD ; month storarg _monthBCD, ax mov ax, word ptr es:[ cl_year ][ di ] mov cx, 100 xor dx, dx div cx push dx ; save remainder call convToBCD ; year storarg _yearBCD, ax pop ax call convToBCD ; century mov cl, al mov ch, byte ptr [ _yearBCD ][ bp ] mov dh, byte ptr [ _monthBCD ][ bp ] mov dl, byte ptr [ _dayBCD ][ bp ] mov ax, 0500h Exint 1Ah ; set date getdarg es, di, _buffer mov al, byte ptr es:[ cl_hours ][ di ] xor ah, ah mov cx, 60 mul cx ; express hours in minutes add al, byte ptr es:[ cl_minutes ][ di ] adc ah, 0 mul cx ; express time in seconds add al, byte ptr es:[ cl_seconds ][ di ] adc ah, 0 mov cx, 182 call _mul32 ; express time in hseconds add al, byte ptr es:[ cl_hseconds ][ di ] adc ah, 0 adc dx, 0 mov cx, 10 call _div32 ; express time in hseconds mov cx, dx mov dx, ax mov ax, 0100h Exint 1Ah ; set date Return ;'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''; ; Get Days Since 1980 ; ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -; ; ; ; Input: ; ; cx year ( 1980 ... ) ; ; dh month ( 1 - 12) ; ; dl day ( 1 - 31) ; ; ; ; Output: ; ; ax days since 1980 format ; ;...............................................................; getDaysSince1980: Entry def _year, cx def _month, 0000 def _day, 0000 def _m14_12, 0000 ddef _daysSince push bx push cx push dx mov byte ptr [ _month ][ bp ], dh mov byte ptr [ _day ][ bp ], dl dec dh jnz getDaysSince1980_06 mov word ptr [ _m14_12 ][ bp ], -1 getDaysSince1980_06: xor dx, dx mov ax, word ptr [ _m14_12 ][ bp ] mov cx, 12 mul cx ; *12 inc ax inc ax ; 2 sub ax, word ptr [ _month ][ bp ] neg ax ; - m_14 mov cx, 367 mul cx xor dx, dx mov cx, 12 div cx mov word ptr [ _daysSince. _Low ][ bp ], ax mov word ptr [ _daysSince. _High ][ bp ], 0000 mov ax, word ptr [ _m14_12 ][ bp ] add ax, 4900 add ax, word ptr [ _year ][ bp ] ;;; jdn = (long)(d - 32076) ;;; + 1461L * (y + 4800L + (m - 14) / 12) / 4 ;;; + 367 * (m - 2 - (m - 14) / 12 * 12) / 12 ;;; - 3 * ((y + 4900L + (m - 14) / 12) / 100) / 4 ;;; + 1; /* correction by rdg */ xor dx, dx mov cx, 100 div cx mov cx, 3 mul cx shr ax, 1 shr ax, 1 ; / 4 dec ax sub word ptr [ _daysSince. _Low ][ bp ], ax sbb word ptr [ _daysSince. _High ][ bp ], 0000 mov ax, word ptr [ _m14_12 ][ bp ] add ax, 4800 add ax, word ptr [ _year ][ bp ] mov cx, 1461 mul cx ; do a long shift here shr dx, 1 rcr ax, 1 shr dx, 1 ; / 4 rcr ax, 1 add word ptr [ _daysSince. _Low ][ bp ], ax adc word ptr [ _daysSince. _High ][ bp ], dx xor dx, dx mov ax, word ptr [ _day ][ bp ] sub ax, 32076 sbb dx, 0000 add ax, word ptr [ _daysSince. _Low ][ bp ] adc dx, word ptr [ _daysSince. _High ][ bp ] sub ax, 4BD0h sbb dx, 25h IFDEF OLDDATE_LOGIC sub cx, 1980 storarg _year, cx mov ax, 365 mul cx ; rough estimate of days shr cx, 1 shr cx, 1 ; # leap years inc cx ; adj for 1980 add ax, cx ; days since storarg _daysSince, ax ; days since as of last year xor ax, ax getarg dx, _monthnDays mov bl, dh and bx, 255 jz getDaysSince1980_08 getDaysSince1980_06: add al, byte ptr cs:[ DaysInMonthTable ][ bx ] adc ah, 0 dec bx jnz getDaysSince1980_06 getDaysSince1980_08: mov dh, 0 ; days only in dx add ax, dx ; days this year cmp ax, 28 ; between Jan 1 and Feb 28 ? jle getDaysSince1980_12 ; yes --> test word ptr [ _year ][ bp ], 11b ; this year a leap year ? jnz getDaysSince1980_12 ; no --> inc ax ; we get one more day add ax, word ptr [ _daysSince ][ bp ] ENDIF getDaysSince1980_12: pop dx pop cx pop bx Return ;'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''; ; Code Segment Data ; ;...............................................................; DaysInMonthTable: db 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 ;'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''; ; Convert AL to BCD form ; ;...............................................................; convToBCD: mov ah, 0 aam ; divide by ten shl ah, 1 shl ah, 1 shl ah, 1 shl ah, 1 ; shift four bits or al, ah ; BCD form mov ah, 0 ret ;'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''; ; Convert BCD to Binary ; ;...............................................................; ConvBCDToBin: mov ah, al and al, 0Fh shr ah, 1 shr ah, 1 shr ah, 1 shr ah, 1 mov ch, ah ; 1 add ah, ah ; 2 add ah, ah ; 4 add ah, ch ; 5 add ah, ah ; 10 add al, ah mov ah, 0 ret ;'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''; ; 32 Bit Multiply ; ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -; ; ; ; Input: ; ; dx:ax numerator ; ; cx multiplier ; ; ; ;...............................................................; _mul32: or dx, dx ; simple multiply ? jnz _mul32_12 ; not really --> mul cx ret _mul32_12: push bx mov bx, ax mov ax, dx mul cx xchg ax, bx mul cx add dx, bx pop bx ; restore bx ret ;'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''; ; 32 Bit Divide ; ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -; ; ; ; Input: ; ; dx:ax numerator ; ; cx divisor ; ; ; ; Output: ; ; dx:ax answer ; ; cx remainder ; ; ; ;...............................................................; _div32: or cx, cx ; protect from zero divisor stc ; in case of error jz _div32_return ; if so, just return with carry push bx mov bx, dx xchg ax, bx xor dx, dx div cx ; divide high order first xchg ax, bx div cx ; REMAINDER WILL BE IN DX mov cx, dx ; save remainder mov dx, bx ; full 32-bit answer pop bx _div32_return: ret ;'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''; ; Con Read (Fct 4) ; ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -; ; ; ; ds:bx points to request header ; ; es:di points to request buffer ; ; cx characters to transfer ; ; dl logical device ; ; ; ; for block devices: ; ; ; ; ah device media (old ) ; ; al block device unit (a: = 0, ... ) ; ;...............................................................; ConRead: or cx, cx ; any input requested ? jz ConRead_22 ; no, failsafe exit --> ConRead_12: call getConData ; read from con device or al, al ; is data an extended char ? jnz ConRead_16 ; no --> cmp cx, 1 ; one character read ? jnz ConRead_12 ; we'll ignore --> stosw ; else save entire 2 bytes xor cx, cx ; all read jmp short ConRead_22 ; then return --> ConRead_16: stosb ; fill data in buffer loop ConRead_12 ; if more data --> ConRead_22: sub word ptr [ rwrBytesReq ][ bx ], cx ret ;'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''; ; Con NonDestructive Read (Fct 5) ; ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -; ; ; ; ds:bx points to request header ; ; es:di points to request buffer ; ; cx characters to transfer ; ; dl logical device ; ;...............................................................; ConNonDestrRead: mov ah, BIOS_ConStatus Int 16h ; see if characters waiting ? jz ConNonDestrRead_NoData ; none waiting --> mov byte ptr [ ndrCharRead ][ bx ], al ; return lookahead character. ret ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ; If no data ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ConNonDestrRead_NoData: mov word ptr [ ndrStatus ][ bx ], (OP_NODATA) ret ;'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''; ; Con Status (Fct 6) ; ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -; ; ; ; ds:bx points to request header ; ; cx characters to transfer ; ; dl logical device ; ; ; ; for block devices: ; ; ; ; ah device media (old ) ; ; al block device unit (a: = 0, ... ) ; ;...............................................................; ConStatus: cmp word ptr cs:[ Con_LookAhead ], 0000 ; character in pending area ? jnz ConStatus_16 ; yes --> mov ah, BIOS_ConStatus Int 16h ; see if characters waiting ? jz ConStatus_NoData ; none waiting --> ConStatus_16: ret ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ; If no data ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ConStatus_NoData: mov word ptr [ rhStatus ][ bx ], (OP_NODATA) ret ;'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''; ; Con Input Flush (Fct 7) ; ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -; ; ; ; ds:bx points to request header ; ; es:di points to request buffer ; ; cx characters to transfer ; ; dl logical device ; ;...............................................................; ConInputFlush: mov word ptr cs:[ Con_LookAhead ], 0000 ; flush input character ConInputFlush_08: mov ah, BIOS_ConStatus Int 16h ; see if characters waiting ? jz ConInputFlush_NoData ; no more --> mov ah, BIOS_ConRead Int 16h ; read waiting character jmp ConInputFlush_08 ; test for more --> ConInputFlush_NoData: ret ;'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''; ; Con Write (Fcts 8, 9) ; ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -; ; ; ; ds:bx points to request header ; ; es:di points to request buffer ; ; cx characters to transfer ; ; dl logical device ; ;...............................................................; ConWrite: or cx, cx jz ConWrite_38 ConWrite_08: mov al, byte ptr es:[ di ] ; get character inc di ; check for raw versus cooked mode cmp al, ControlM ; carriage return ? jnz ConWrite_12 ; no --> mov word ptr cs:[ Con_TabPosition ], 0000 ; set tab position jmp short ConWrite_28 ConWrite_12: cmp al, ControlI ; tab character ? jnz ConWrite_22 ; no, display as is --> ConWrite_14: mov al, ' ' ; display a space Int 29h ; internal Video Driver inc byte ptr cs:[ Con_TabPosition ] ; tab position test byte ptr cs:[ Con_TabPosition ], 7 ; tab position jnz ConWrite_14 jmp short ConWrite_32 ConWrite_22: cmp al, ControlJ ; line feed ? jz ConWrite_28 ; yes --> inc byte ptr cs:[ Con_TabPosition ] ; tab position ConWrite_28: Int 29h ; internal Video Driver ConWrite_32: loop ConWrite_08 ; go get additional characters --> ConWrite_38: ret ;'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''; ; Get Con Character ; ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -; ; ds:bx points to request header ; ; dl logical device ; ;...............................................................; getConData: xor ax, ax xchg ax, word ptr cs:[ Con_LookAhead ] ; get char waiting or ax, ax ; any character waiting ? jnz getConData_08 ; no --> mov ah, BIOS_ConRead Int 16h ; wait for character or ax, ax ; anything returned ? jz getConData ; continue looping --> getConData_08: mov byte ptr cs:[ Con_ScanCode ], ah ; save scan code ret ;'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''; ; Prn Output Characters (Fct 8, 9) ; ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -; ; ; ; ds:bx points to request header ; ; es:di points to request buffer ; ; cx characters to transfer ; ; dl logical device ; ;...............................................................; PrnWrite: or cx, cx jz PrnWrite_16 PrnWrite_08: mov bx, Prn_RetryCount PrnWrite_10: mov ah, BIOS_PrnWrite mov al, byte ptr es:[ di ] inc di Int 17h mov al, devErrDeviceNotReady test ax, Prn_IOError ; i/o error ? jnz PrnWrite_Retry ; yes --> test ax, Prn_TimeOut ; operation timed out ? jz PrnWrite_14 ; no --> PrnWrite_Retry: dec di dec bx jnz PrnWrite_10 jmp short PrnWrite_WriteFault PrnWrite_14: loop PrnWrite_08 PrnWrite_16: ret ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ; If no data ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - PrnWrite_WriteFault: test ax, Prn_OutOfPaper jz PrnWrite_WriteFault_08 mov al, devErrPrinterOutPaper PrnWrite_WriteFault_08: or ax, OP_EXITERROR mov word ptr [ rwrStatus ][ bx ], ax ret ;'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''; ; Prn Output Status (Fct 10) ; ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -; ; ; ; ds:bx points to request header ; ; es:di points to request buffer ; ; cx characters to transfer ; ; dl logical device ; ;...............................................................; PrnStatus: mov ah, BIOS_PrnStatus Int 17h ;** this is wrong mov al, devErrDeviceNotReady test ax, Prn_OutOfPaper ; out of paper ? jz PrnStatus_08 ; no --> mov al, devErrPrinterOutPaper PrnStatus_08: xor ah, ah or ax, OP_EXITERROR mov word ptr [ rwrStatus ][ bx ], ax ret ;'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''; ; Com Read (Fct 4) ; ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -; ; ; ; ds:bx points to request header ; ; es:di points to request buffer ; ; cx characters to transfer ; ; dl logical device ; ; ; ; for block devices: ; ; ; ; ah device media (old ) ; ; al block device unit (a: = 0, ... ) ; ;...............................................................; AuxRead: or cx, cx jz AuxRead_16 AuxRead_12: call getComData ; read from comm device test ax, (CommLS_FE + CommLS_PE + CommLS_OE) jnz AuxRead_Error ; if errors (no data or timeout) --> stosb ; fill data in buffer loop AuxRead_12 ; if more data --> AuxRead_16: mov word ptr [ rwrBytesReq ][ bx ], 0000 ret ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ; if error ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - AuxRead_Error: sub word ptr [ rwrBytesReq ][ bx ], cx mov word ptr [ rwrStatus ][ bx ], (devErrReadFault + OP_EXITERROR) ret ;'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''; ; Com NonDestructive Read (Fct 5) ; ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -; ; ; ; ds:bx points to request header ; ; es:di points to request buffer ; ; cx characters to transfer ; ; dl logical device ; ;...............................................................; AuxNonDestrRead: call getComStatus ; read from comm device test ax, CommLS_DataAvail ; data available ? jz AuxNonDestrRead_NoData ; if no data --> test ax, CommMS_DSR ; DSR ? jz AuxNonDestrRead_NoData ; if no dsr --> ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ; If Data Available, read data (lookahead) ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - call getComData jnz AuxRead_Error ; if no data or timeout --> mov si, dx add si, offset Comm_LookAhead ; mov byte ptr cs:[ si ], al ; save waiting data. mov byte ptr [ ndrCharRead ][ bx ], al ; return lookahead character. ret ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ; If no data ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - AuxNonDestrRead_NoData: mov word ptr [ ndrStatus ][ bx ], (OP_NODATA) ret ;'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''; ; Aux Input Flush (Fct 7) ; ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -; ; ; ; ds:bx points to request header ; ; es:di points to request buffer ; ; cx characters to transfer ; ; dl logical device ; ;...............................................................; AuxInputFlush: mov si, dx add si, offset Comm_LookAhead ; mov byte ptr cs:[ si ], 00 ; flush input character ret ;'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''; ; Aux Output Characters (Fct 8, 9) ; ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -; ; ; ; ds:bx points to request header ; ; es:di points to request buffer ; ; cx characters to transfer ; ; dl logical device ; ;...............................................................; AuxWrite: or cx, cx jz AuxWrite_16 AuxWrite_12: mov ah, BIOS_ComWrite mov al, byte ptr es:[ di ] inc di Int 14h test ax, CommLS_TimeOut jnz AuxWrite_WriteFault loop AuxWrite_12 AuxWrite_16: ret ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ; If no data ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - AuxWrite_WriteFault: mov word ptr [ rwrStatus ][ bx ], (devErrWriteFault + OP_EXITERROR) ret ;'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''; ; Aux Output Status (Fct 10) ; ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -; ; ; ; ds:bx points to request header ; ; es:di points to request buffer ; ; cx characters to transfer ; ; dl logical device ; ;...............................................................; AuxOutputStatus: mov ah, BIOS_ComStatus Int 14h test ax, CommMS_DSR jz AuxOutputStatus_08 test ax, CommLS_HoldRegEmpty jnz AuxOutputStatus_12 AuxOutputStatus_08: mov word ptr [ rwrStatus ][ bx ], OP_NODATA AuxOutputStatus_12: ret ;'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''; ; Get Com Character ; ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -; ; ds:bx points to request header ; ; dl logical device ; ;...............................................................; getComData: mov si, dx add si, offset Comm_LookAhead ; cmp byte ptr cs:[ si ], 00 ; data waiting ? jz getComData_08 ; no --> xor ax, ax xchg al, byte ptr cs:[ si ] ; get char waiting ret getComData_08: mov ah, BIOS_ComRead Int 14h test ax, (CommLS_FE + CommLS_PE + CommLS_OE) ; errors ?? ret ;'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''; ; Get Com Status ; ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -; ; ds:bx points to request header ; ; dl logical device ; ;...............................................................; getComStatus: mov si, dx add si, offset Comm_LookAhead ; cmp byte ptr cs:[ si ], 00 ; data waiting ? jz getComStatus_08 ; no --> mov ax, CommLS_DataAvail mov al, byte ptr cs:[ si ] ; get char waiting ret getComStatus_08: mov ah, BIOS_ComStatus Int 14h ret ;'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''; ; Interrupt 29 ; ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -; ; ; ; al character to display ; ;...............................................................; Interrupt_29 proc far sti saveAllRegisters mov ah, 0Eh ; write teletype mov bx, 0007h ; default page 0, color 07 Int 10h restoreAllRegisters iret Interrupt_29 endp ;'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''; ; Divide by Zero ; ;...............................................................; Interrupt_0 proc far jmp dword ptr cs:[ DivideByZero ] Interrupt_0 endp DivideByZero: dd 0 ; BIOS value ;'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''; ; General Interrupt Trap ; ;...............................................................; IntReturn proc far iret IntReturn endp ;'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''; ; Block Device Functions ; ;...............................................................; ;'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''; ; Block Device Init ; ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -; ; ; ; Input: ; ; DS:BX request header ; ; ES:DI buffer ; ; CX characters to transfer ; ;...............................................................; _hdInit: Entry ddef _packet, ds, bx mov al, byte ptr cs:[ block. devUnits ] mov byte ptr [ irUnits ][ bx ], al ; set max units available mov word ptr [ irEndAddress. _pointer ][ bx ], offset RxDOSBIOS_LastAddress mov word ptr [ irEndAddress. _segment ][ bx ], cs mov word ptr [ irParamAddress. _pointer ][ bx ], NULL mov word ptr [ irParamAddress. _segment ][ bx ], NULL ; BPB address mov al, byte ptr [ irUnit ][ bx ] ; find Disk block call BuildDiskParameterBlock ; es: di push word ptr [ _packet. _segment ][ bp ] push word ptr [ _packet. _pointer ][ bp ] call SetInvalidDriveError ; if error, set error code --> jc _hdInit_12 ; then exit getdarg ds, bx, _packet lea di, offset _dskBPB [ di ] mov word ptr [ irParamAddress. _pointer ][ bx ], di mov word ptr [ irParamAddress. _segment ][ bx ], es call stampTimerCount _hdInit_12: Return ;'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''; ; Block Device Media Descriptor ; ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -; ; ; ; Input: ; ; DS:BX request header ; ; ES:DI buffer ; ; CX characters to transfer ; ;...............................................................; _hdMediaCheck: Entry ddef _packet, ds, bx mov al, byte ptr [ mrUnit ][ bx ] ; get unit requested call BuildDiskParameterBlock ; es: di push word ptr [ _packet. _segment ][ bp ] push word ptr [ _packet. _pointer ][ bp ] call SetInvalidDriveError ; if error, set error code --> jc _hdMediaCheck_12 getdarg ds, bx, _packet mov cl, byte ptr es:[ _dskBPB. _bpbMediaDescriptor ][ di ] mov byte ptr [ mrMediaID ][ bx ], cl ; media ID mov dx, word ptr es:[ _dskSerialNumber. _High ][ di ] mov ax, word ptr es:[ _dskSerialNumber. _Low ][ di ] mov word ptr [ mrVolumeID. _High ][ bx ], dx mov word ptr [ mrVolumeID. _Low ][ bx ], ax mov byte ptr [ mrReturn ][ bx ], MEDIA_UNCHANGED test word ptr es:[ _dskStatusFlag ][ di ], DiskChangeDetected jz _hdMediaCheck_12 ; not changed --> mov byte ptr [ mrReturn ][ bx ], MEDIA_HASCHANGED _hdMediaCheck_12: Return ;'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''; ; Block Device Build BPB ; ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -; ; ; ; Input: ; ; DS:BX request header ; ; ES:DI buffer ; ; CX characters to transfer ; ;...............................................................; _hdBuildBPB: Entry ddef _packet, ds, bx mov word ptr [ bbrBPBAddress. _pointer ][ bx ], NULL mov word ptr [ bbrBPBAddress. _segment ][ bx ], NULL mov al, byte ptr [ bbrUnit ][ bx ] ; get unit requested call BuildDiskParameterBlock ; es: di push word ptr [ _packet. _segment ][ bp ] push word ptr [ _packet. _pointer ][ bp ] call SetInvalidDriveError ; if error, set error code --> jc _hdBuildBPB_12 mov al, cl ; Media Descriptor lea di, offset _dskBPB [ di ] ; getdarg ds, bx, _packet mov byte ptr [ bbrMediaID ][ bx ], al ; media ID mov word ptr [ bbrBPBAddress. _pointer ][ bx ], di mov word ptr [ bbrBPBAddress. _segment ][ bx ], es call stampTimerCount _hdBuildBPB_12: Return ;'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''; ; Block Device Build BPB ; ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -; ; ; ; Input: ; ; DS:BX request header ; ; ES:DI buffer ; ; CX sectors to transfer ; ;...............................................................; _hdRead: Entry ddef _packet, ds, bx ddef _buffer, es, di ddef _diskparameters ddef _logSector def _numSectorsRemain, cx def _numSectorsRead, cx def _numSectorsTotal, 0000 xor dx, dx mov ax, word ptr [ rwrStartSec ][ bx ] ; get start sector address cmp ax, -1 ; use huge instead ? jnz _hdRead_08 ; if not --> mov ax, word ptr [ rwrHugeStartSec. _low ][ bx ] ; get huge sector mov dx, word ptr [ rwrHugeStartSec. _high ][ bx ] _hdRead_08: stordarg _logSector, dx, ax mov al, byte ptr [ rwrUnit ][ bx ] ; get unit requested call FindDiskParameterBlock ; make sure disk is fine stordarg _diskparameters, es, di push word ptr [ _packet. _segment ][ bp ] push word ptr [ _packet. _pointer ][ bp ] call SetInvalidDriveError ; if error, set error code --> jc _hdRead_20 cmp word ptr [ _numSectorsRemain ][ bp ], 0000 ; read no sectors ? jz _hdRead_20 ; just a read test --> _hdRead_12: getdarg es, di, _diskparameters getdarg dx, ax, _logSector call ConvertLogSectorToPhysical mov ax, word ptr es:[ _dskBPB. _bpbSectorsPerTrack ][ di ] mov bx, cx ; sector and bx, 003Fh ; drop high order cyl portion sub ax, bx ; sectors remaining in track inc ax ; real number is inclusive cmp ax, word ptr [ _numSectorsRemain ][ bp ] ; more than sectors requested ? jc _hdRead_16 ; if carry, only allow max --> mov ax, word ptr [ _numSectorsRemain ][ bp ] ; more than sectors requested ? _hdRead_16: mov word ptr [ _numSectorsRead ][ bp ], ax ; temporary mov ah, 02h ; read function getdarg es, bx, _buffer call DiskFunctionsWithRetry ;; pushf ;; mov word ptr [ _numSectorsRead ][ bp ], cx ;; add word ptr [ _numSectorsTotal ][ bp ], cx ;; popf push word ptr [ _packet. _segment ][ bp ] push word ptr [ _packet. _pointer ][ bp ] call setPacketReqError ; if error jc _hdRead_20 mov ax, word ptr [ _numSectorsRead ][ bp ] add word ptr [ _numSectorsTotal ][ bp ], ax ; total add word ptr [ _logSector. _low ][ bp ], ax adc word ptr [ _logSector. _high ][ bp ], 0000 xchg ah, al shl ah, 1 add word ptr [ _buffer. _pointer ][ bp ], ax mov ax, word ptr [ _numSectorsRead ][ bp ] sub word ptr [ _numSectorsRemain ][ bp ], ax ; compute how many more to go jg _hdRead_12 ; if more to go --> clc _hdRead_20: pushf getdarg es, di, _diskparameters call stampTimerCount getdarg ds, bx, _packet mov ax, word ptr [ _numSectorsTotal ][ bp ] mov word ptr [ rwrBytesReq ][ bx ], ax ; sectors read popf Return ;'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''; ; Block Device Build BPB ; ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -; ; ; ; Input: ; ; DS:BX request header ; ; ES:DI buffer ; ; CX characters to transfer ; ;...............................................................; _hdWrite: _hdWriteWithVerify: Entry ddef _packet, ds, bx ddef _buffer, es, di ddef _diskparameters ddef _logSector def _numSectors, cx def _numSectorsTotal, cx def _Verify, ax xor dx, dx mov ax, word ptr [ rwrStartSec ][ bx ] ; get start sector address cmp ax, -1 ; use huge instead ? jnz _hdWrite_08 ; if not --> mov ax, word ptr [ rwrHugeStartSec. _low ][ bx ] ; get huge sector mov dx, word ptr [ rwrHugeStartSec. _high ][ bx ] _hdWrite_08: stordarg _logSector, dx, ax getdarg ds, bx, _packet cmp word ptr [ _numSectors ][ bp ], 0000 ; sectors == zero ? ifz _hdWrite_20 ; if none --> mov al, byte ptr [ rwrUnit ][ bx ] ; get unit requested call FindDiskParameterBlock ; make sure disk is fine stordarg _diskparameters, es, di push word ptr [ _packet. _segment ][ bp ] push word ptr [ _packet. _pointer ][ bp ] call SetInvalidDriveError ; if error, set error code --> jc _hdWrite_20 ; exit --> _hdWrite_12: getdarg es, di, _diskparameters getdarg dx, ax, _logSector call ConvertLogSectorToPhysical getdarg es, bx, _buffer NormalizeBuffer es, bx mov ax, 0301h ; write sector. call DiskFunctionsWithRetry push word ptr [ _packet. _segment ][ bp ] push word ptr [ _packet. _pointer ][ bp ] call setPacketReqError ; if error jc _hdWrite_20 getdarg ds, bx, _packet cmp byte ptr [ rhFunction ][ bx ], DEVICEWRITEVERIFY jnz _hdWrite_16 ; if not verify --> getdarg es, bx, _buffer NormalizeBuffer es, bx mov ax, 0401h ; verify sector. call DiskFunctionsWithRetry push word ptr [ _packet. _segment ][ bp ] push word ptr [ _packet. _pointer ][ bp ] call setPacketReqError ; if error jc _hdWrite_20 _hdWrite_16: add word ptr [ _buffer. _pointer ][ bp ], sizeSector add word ptr [ _logSector. _low ][ bp ], 0001 adc word ptr [ _logSector. _high ][ bp ], 0000 dec word ptr [ _numSectors ][ bp ] jnz _hdWrite_12 clc _hdWrite_20: pushf getdarg es, di, _diskparameters call stampTimerCount getdarg ds, bx, _packet mov ax, word ptr [ _numSectorsTotal ][ bp ] sub ax, word ptr [ _numSectors ][ bp ] mov word ptr [ rwrBytesReq ][ bx ], ax ; sectors read popf Return ;'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''; ; Hard Disk Functions ; ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -; ; ; ; Input: ; ; ES:BX request header ; ;...............................................................; _hdIOCTLRead: _hdIOCTLWrite: _hdOpenDevice: _hdCloseDevice: _hdRemovableMedia: _hdGenericIOCTL: _hdGetLogicalDevice: _hdSetLogicalDevice: _hdIOCTLQuery: jmp _NoAction ;'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''; ; Convert Log Sector Address To Physical ; ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -; ; ; ; Input: ; ; ES:DI disk parameter block address ; ; AX:DX logical sector address ; ; ; ; Output: ; ; ES:DI disk parameter block address ; ; CX CL = sector/ CH = track ; ; DX DL = unit/ DH = head ; ;...............................................................; ConvertLogSectorToPhysical: add ax, word ptr es:[ _dskBPB. _bpbHiddenSectors. _low ][ di ] adc dx, word ptr es:[ _dskBPB. _bpbHiddenSectors. _high ][ di ] mov cx, word ptr es:[ _dskBPB. _bpbSectorsPerTrack ][ di ] call _div32 inc cx push cx ; sector mov cx, word ptr es:[ _dskBPB. _bpbHeads ][ di ] call _div32 ; track is at ax ; head is at cx mov dh, cl ; head mov dl, byte ptr es:[ _dskPhysDriveNumber ][ di ] ; unit clc shl ah, 1 shl ah, 1 shl ah, 1 shl ah, 1 shl ah, 1 shl ah, 1 ; move high order of cyl up pop cx or cl, ah ; top two bits of cyl or'd into phys sector mov ch, al ; rest of cyl ret ;'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''; ; Rebuild BIOS Parameter Block (if disk changed) ; ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -; ; ; ; Input: ; ; ES:DI Disk Parameter Block Address (unitialized) ; ; ; ; Output: ; ; ES:DI Disk Parameter Block Address, if carry not set. ; ; ZR if diskette not changed ; ; NZ if diskette changed ; ;...............................................................; _ChangedLineSet: push es push di and word ptr es:[ _dskStatusFlag ][ di ], NOT DiskChangeDetected cmp byte ptr es:[ _dskDeviceType ][ di ], -1 ; device entry not initialized ? jz _ChangedLineSet_ChangeLineSet ; set as changed --> test word ptr es:[ _dskStatusFlag ][ di ], IsNonRemovable jnz _ChangedLineSet_notChanged call GetTimerCount ; timer count into dx:ax sub ax, word ptr es:[ _dskClockAtLastOp. _low ][ di ] sbb dx, word ptr es:[ _dskClockAtLastOp. _high ][ di ] cmp ax, 18 * 2 ; within 2 seconds ? jc _ChangedLineSet_notChanged ; line not changed --> mov ah, 16h mov dl, byte ptr es:[ _dskPhysDriveNumber ][ di ] call DiskFunctions ; see if change line set ; jc _ChangedLineSet_ChangeLineSet ; assume changed --> cmp ah, 06h ; diskette change line set ? jnz _ChangedLineSet_notChanged _ChangedLineSet_ChangeLineSet: or word ptr es:[ _dskStatusFlag ][ di ], DiskChangeDetected _ChangedLineSet_notChanged: pop di pop es test word ptr es:[ _dskStatusFlag ][ di ], DiskChangeDetected ret ;'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''; ; Get BIOS Timer Count ; ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -; ; ; ; Output: ; ; dx:ax BIOS Timer Value ; ;...............................................................; GetTimerCount: push es push di xor ax, ax mov es, ax ; mov di, offset 46Ch mov ax, word ptr es:[ 46Ch ] mov dx, word ptr es:[ 46Eh ] pop di pop es ret ;'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''; ; Get BIOS Timer Count ; ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -; ; ; ; Output: ; ; dx:ax BIOS Timer Value ; ;...............................................................; stampTimerCount: push ax push dx push es push di xor ax, ax mov es, ax ; mov di, offset 46Ch mov ax, word ptr es:[ 46Ch ] mov dx, word ptr es:[ 46Eh ] pop di pop es mov word ptr es:[ _dskClockAtLastOp. _low ][ di ], ax mov word ptr es:[ _dskClockAtLastOp. _high ][ di ], dx pop dx pop ax ret ;'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''; ; Rebuild BIOS Parameter Block (if disk changed) ; ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -; ; ; ; Input: ; ; ES:DI Disk Parameter Block Address, if carry not set. ; ; ; ; Output: ; ; ES:DI Disk Parameter Block Address, if carry not set. ; ; CY if error. ; ;...............................................................; RebuildBPB: Entry ddef _dskParameterTable, es, di push ds setDS cs ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ; Rebuild BIOS Parameter Block ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - _RebuildBPB_12: mov dl, byte ptr es:[ _dskPhysDriveNumber ][ di ] mov dh, byte ptr es:[ _dskPartitionBeginHead ][ di ] mov cx, word ptr es:[ _dskPartitionBeginSector ][ di ] mov ax, 0201h setES cs mov bx, offset RxDOSBIOS_DiskBuffer call DiskFunctionsWithRetry jc _RebuildBPB_38 ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ; Validate Boot Sector ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ; cmp byte ptr [ RxDOSBIOS_DiskBuffer + _bsJump ], 0EBh ; must be jump ; jnz ... getdarg es, di, _dskParameterTable lea si, RxDOSBIOS_DiskBuffer + _bsBytesPerSector lea di, offset _dskBPB [ di ] mov cx, sizeBPB rep movsb mov di, word ptr [ _dskParameterTable ][ bp ] mov ax, word ptr [ _dskExtHiddenSectors. _low ][ di ] mov dx, word ptr [ _dskExtHiddenSectors. _high ][ di ] add word ptr [ _dskBPB. _bpbHiddenSectors. _low ][ di ], ax adc word ptr [ _dskBPB. _bpbHiddenSectors. _high ][ di ], dx ; copy serial number mov di, word ptr [ _dskParameterTable ][ bp ] mov ax, word ptr [ RxDOSBIOS_DiskBuffer. _bsVolumeId. _Low ] mov dx, word ptr [ RxDOSBIOS_DiskBuffer. _bsVolumeId. _High ] mov word ptr [ _dskSerialNumber. _Low ][ di ], ax mov word ptr [ _dskSerialNumber. _High ][ di ], dx ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ; Determine FAT Size ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - getdarg es, di, _dskParameterTable mov byte ptr es:[ _dskDeviceType ][ di ], DSKFILESYSTYPE_IsValid _RebuildBPB_36: getdarg es, di, _dskParameterTable mov cl, byte ptr es:[ _dskBPB. _bpbMediaDescriptor ][ di ] clc _RebuildBPB_38: pop ds Return ;'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''; ; Init Reset Drive ; ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -; ; ; ; Input: ; ; ES:DI Disk Parameter Block Address, if carry not set. ; ; ; ; Output: ; ; CY if error. ; ;...............................................................; InitResetDrive: cmp byte ptr es:[ _dskDeviceType ][ di ], -1 ; device entry not initialized ? clc ; (set no error ) jnz InitResetDrive_08 ; if already initialized --> mov word ptr es:[ _dskStatusFlag ][ di ], 0000 ; no flags mov dl, byte ptr es:[ _dskPhysDriveNumber ][ di ] test dl, 80h ; fixed drive ? jz InitResetDrive_06 ; no --> or word ptr es:[ _dskStatusFlag ][ di ], IsNonRemovable InitResetDrive_06: mov ah, 00h call DiskFunctions ; reset drive push es push di or word ptr es:[ _dskStatusFlag ][ di ], ActiveUnit mov ax, 0800h mov dl, byte ptr es:[ _dskPhysDriveNumber ][ di ] call DiskFunctionsWithRetry ; get disk parameters mov bx, es or bx, di ; disk parameter table == 0 ? pop di pop es ; restore pointr to jnz InitResetDrive_08 ; if valid drive --> and word ptr es:[ _dskStatusFlag ][ di ], NOT ActiveUnit stc ; set carry (error ) flag InitResetDrive_08: ret ;'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''; ; Build Disk Parameter Block ; ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -; ; ; ; Input: ; ; al DOS disk unit. ; ; ; ; Output: ; ; es:di Disk Parameter Block Address, if carry not set. ; ; cy if error. ; ;...............................................................; BuildDiskParameterBlock: cmp word ptr cs:[ ptr_StartBlockedDeviceTable. _segment ], 0000 stc ; assume not initialized jz _buildDPB_20 ; if not initialized --> les di, dword ptr cs:[ ptr_StartBlockedDeviceTable ] _buildDPB_08: cmp al, byte ptr es:[ _dskDOSLogicalDiskUnit ][ di ] jz _buildDPB_12 ; if logical unit -> cmp word ptr es:[ _dskNextPointer. _pointer ][ di ], -1 stc ; assume end of list jz _buildDPB_20 ; if end of list --> les di, dword ptr es:[ _dskNextPointer ][ di ] jmp _buildDPB_08 ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ; if never initialized or disk change suspected, rebuild BPB ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - _buildDPB_12: call InitResetDrive ; is drive valid ? jc _buildDPB_18 ; no --> test word ptr es:[ _dskStatusFlag ][ di ], ActiveUnit jz _buildDPB_18 ; if unit is invalid --> call _ChangedLineSet ; see if removable jz _buildDPB_20 ; if line not changed --> call RebuildBPB ; else rebuild BPB jnc _buildDPB_20 ; exit if no error --> _buildDPB_18: stc ; error exit _buildDPB_20: ret ;'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''; ; Find Block Device Info ; ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -; ; ; ; Input: ; ; al DOS disk unit. ; ; ; ; Output: ; ; es:di Disk Parameter Block Address, if carry not set. ; ; cy if error. ; ;...............................................................; FindDiskParameterBlock: cmp word ptr cs:[ ptr_StartBlockedDeviceTable. _segment ], 0000 stc ; assume not initialized jz _findDPB_20 ; if not initialized --> les di, dword ptr cs:[ ptr_StartBlockedDeviceTable ] _findDPB_08: cmp al, byte ptr es:[ _dskDOSLogicalDiskUnit ][ di ] jz _findDPB_12 ; if logical unit -> cmp word ptr es:[ _dskNextPointer. _pointer ][ di ], -1 stc ; assume end of list jz _findDPB_20 ; if end of list --> les di, dword ptr es:[ _dskNextPointer ][ di ] jmp _findDPB_08 ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ; if never initialized or disk change suspected, rebuild BPB ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - _findDPB_12: cmp byte ptr es:[ _dskDeviceType ][ di ], -1 ; device entry not initialized ? jnz _findDPB_14 ; if already init --> call InitResetDrive ; is drive valid ? jc _findDPB_18 ; if error --> _findDPB_14: test word ptr es:[ _dskStatusFlag ][ di ], ActiveUnit jz _findDPB_18 ; if unit is invalid --> call _ChangedLineSet ; see if removable jz _findDPB_20 ; if line not changed --> call RebuildBPB ; else rebuild BPB jnc _findDPB_20 ; exit if no error --> _findDPB_18: stc ; if error --> _findDPB_20: ret ;'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''; ; Initialize Block Device Info ; ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -; ; ; ; Input: ; ; cx number of fixed disks to initialize ; ; dx number of floppy disks to initialize ; ;...............................................................; initDiskParameterBlocks: Entry def _fixeddevices, cx def _floppydevices, dx def _devices, 0002 def _physicalDrive, 80h mov ax, cs mov es, ax mov ds, ax add cx, dx ; total # of devices mov ax, sizeDISKBLOCK ; multiply by size mul cx mov cx, ax ; save size in cx or cx, cx ; no devices ? ifz _initDiskParams_36 ; then exit --> mov di, offset RxDOS_StartBlockedDeviceTable clearMemory ; init clear ; make first two devices disk A: and B: mov di, offset RxDOS_StartBlockedDeviceTable mov byte ptr [ _dskPhysDriveNumber ][ di ], 00h ; A: mov byte ptr [ _dskDOSLogicalDiskUnit ][ di ], 00 ; A: mov byte ptr [ _dskDeviceType ][ di ], -1 ; say device not init mov byte ptr [ _dskPartitionBeginHead ][ di ], 0 mov byte ptr [ _dskPartitionBeginCylinder][ di ], 0 mov byte ptr [ _dskPartitionBeginSector ][ di ], 1 lea bx, sizeDISKBLOCK [ di ] mov word ptr [ _dskNextPointer. _segment ][ di ], ds mov word ptr [ _dskNextPointer. _pointer ][ di ], bx mov di, bx ; go to next drive mov byte ptr [ _dskPhysDriveNumber ][ di ], 01h ; B: mov byte ptr [ _dskDOSLogicalDiskUnit ][ di ], 01 ; B: mov byte ptr [ _dskDeviceType ][ di ], -1 ; say device not init mov byte ptr [ _dskPartitionBeginHead ][ di ], 0 mov byte ptr [ _dskPartitionBeginCylinder][ di ], 0 mov byte ptr [ _dskPartitionBeginSector ][ di ], 1 lea bx, sizeDISKBLOCK [ di ] mov word ptr [ _dskNextPointer. _segment ][ di ], ds mov word ptr [ _dskNextPointer. _pointer ][ di ], bx mov di, bx ; go to next drive ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ; initialize all remaining devices to hard disks, link list all blocks ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - cmp word ptr _fixeddevices[ bp ], 0000 ; any fixed devices ? jz _initDiskParams_32 ; no --> _initDiskParams_12: mov dx, word ptr [ _physicalDrive ][ bp ] ; physical disk unit mov ax, word ptr [ _devices ][ bp ] ; current devices counter call mapAllStandardDOSPartitions mov word ptr [ _devices ][ bp ], ax ; additional devices inc word ptr [ _physicalDrive ][ bp ] ; physical disk unit dec word ptr [ _fixeddevices ][ bp ] ; more phys devices to go ? jnz _initDiskParams_12 ; if yes --> ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ; set end of list ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - _initDiskParams_32: lea bx, ( -sizeDISKBLOCK) [ di ] mov word ptr [ _dskNextPointer. _pointer ][ bx ], -1 ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ; end, return ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - _initDiskParams_36: mov word ptr [ ptr_StartBlockedDeviceTable. _segment ], cs mov word ptr [ ptr_StartBlockedDeviceTable. _pointer ], offset RxDOS_StartBlockedDeviceTable getarg cx, _devices ; total devices (floppy + fixed). Return ;'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''; ; Scan Standard DOS Partitions ; ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -; ; ; ; Input: ; ; ax current devices ; ; cx:dx partition table physical address ; ; ds:di drive table to create ; ; ; ; Output: ; ; ds:di drive table to create (points to end of table ) ; ; ax current devices ; ; ; ;...............................................................; mapAllStandardDOSPartitions: Entry def _devices, ax def _entries, 4 def _physaddressDX, dx ddef _additionalSectorOffset, 0000, 0000 ddef _PartitionTablePtr, ss, si ddef _DiskParameterTablePtr, es, di defbytes _PhysPartitionTable, sizePARTITIONTABLE mov cx, 0001h ; assume at boot sector or dh, dh ; extended or sec part table ? jz _mapStandardPartitions_08 ; no, arguments already in cx:dx mov ax, word ptr ss:[ _ptStartSector. _low ][ si ] mov dx, word ptr ss:[ _ptStartSector. _high ][ si ] mov word ptr [ _additionalSectorOffset. _low ][ bp ], ax mov word ptr [ _additionalSectorOffset. _high ][ bp ], dx mov dl, byte ptr [ _physaddressDX ][ bp ] ; physical drive mov dh, byte ptr ss:[ _ptBeginHead ][ si ] ; begin head address mov cx, word ptr ss:[ _ptBeginSector ][ si ] ; begin sector address _mapStandardPartitions_08: call ReadPartitionTable ifc _mapStandardPartitions_36 setDS es ; es: si --> ds: si setES ss ; ss: di --> es: di lea di, word ptr _PhysPartitionTable [ bp ] mov cx, sizePARTITIONTABLE fastmove lea si, word ptr _PhysPartitionTable [ bp ] ; restore pointer getdarg es, di, _DiskParameterTablePtr ; disk parameter table to build _mapStandardPartitions_12: mov al, byte ptr ss:[ _ptFileSystemName ][ si ] cmp al, FILESYSID_12FAT ; 12-bit FAT (max 10 MBytes) jz _mapStandardPartitions_16 cmp al, FILESYSID_16FAT ; 16-bit FAT (max 32 MBytes) jz _mapStandardPartitions_16 cmp al, FILESYSID_LARGE16FAT ; 16-bit FAT (greater than 32 MBytes) jz _mapStandardPartitions_16 ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ; process extended partition ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - cmp al, FILESYSID_EXTENDED ; Extended DOS partition ifnz _mapStandardPartitions_24 ; if not DOS file system --> push si mov ax, word ptr [ _devices ][ bp ] ; device assignment mov dl, byte ptr [ _physaddressDX ][ bp ] ; physical drive mov dh, -1 ; say read additional params from part table. call mapAllStandardDOSPartitions ; recursive call; di preserved mov word ptr [ _devices ][ bp ], ax ; device assignment pop si jmp _mapStandardPartitions_24 ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ; process standard partition ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - _mapStandardPartitions_16: clearMemory sizeDISKBLOCK ; clear area for each item mov al, byte ptr [ _physaddressDX ][ bp ] mov ah, byte ptr [ _devices ][ bp ] mov byte ptr [ _dskPhysDriveNumber ][ di ], al mov byte ptr [ _dskDOSLogicalDiskUnit ][ di ], ah mov word ptr [ _dskStatusFlag ][ di ], IsNonRemovable mov byte ptr [ _dskDeviceType ][ di ], -1 ; say device not init mov al, byte ptr ss:[ _ptBeginHead ][ si ] ; begin head address mov dx, word ptr ss:[ _ptBeginSector ][ si ] ; begin sector address mov byte ptr [ _dskPartitionBeginHead ][ di ], al mov word ptr [ _dskPartitionBeginSector ][ di ], dx mov al, byte ptr ss:[ _ptEndHead ][ si ] ; end head address mov dx, word ptr ss:[ _ptEndSector ][ si ] ; end sector address mov byte ptr [ _dskPartitionEndHead ][ di ], al mov word ptr [ _dskPartitionEndSector ][ di ], dx mov ax, word ptr ss:[ _ptSectors. _low ][ si ] mov dx, word ptr ss:[ _ptSectors. _high ][ si ] mov word ptr [ _dskBPB. _bpbMaxSectors ][ di ], ax or dx, dx ; small volume ? jz _mapStandardPartitions_20 ; yes --> mov word ptr [ _dskBPB. _bpbMaxSectors ][ di ], 0000 mov word ptr [ _dskBPB. _bpbHugeSectors. _low ][ di ], ax mov word ptr [ _dskBPB. _bpbHugeSectors. _high ][ di ], dx _mapStandardPartitions_20: mov ax, word ptr [ _additionalSectorOffset. _low ][ bp ] mov dx, word ptr [ _additionalSectorOffset. _high ][ bp ] mov word ptr [ _dskExtHiddenSectors. _low ][ di ], ax mov word ptr [ _dskExtHiddenSectors. _high ][ di ], dx add ax, word ptr ss:[ _ptStartSector. _low ][ si ] adc dx, word ptr ss:[ _ptStartSector. _high ][ si ] mov word ptr [ _dskBPB. _bpbHiddenSectors. _low ][ di ], ax mov word ptr [ _dskBPB. _bpbHiddenSectors. _high ][ di ], dx lea bx, sizeDISKBLOCK [ di ] mov word ptr [ _dskNextPointer. _segment ][ di ], cs mov word ptr [ _dskNextPointer. _pointer ][ di ], bx mov di, bx ; go to next drive mov word ptr [ _DiskParameterTablePtr. _pointer ][ bp ], di inc word ptr [ _devices ][ bp ] _mapStandardPartitions_24: add si, sizePARTITION dec word ptr [ _entries ][ bp ] ; more entries ? ifnz _mapStandardPartitions_12 ; yes --> clc mov ax, word ptr [ _devices ][ bp ] ; return updated devices _mapStandardPartitions_36: Return ;'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''; ; Read Partition Table ; ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -; ; ; ; Input: ; ; dl drive ; ; ; ; Output: ; ; cs:si partition table address ; ; ax signature word ; ; ; ;...............................................................; ReadPartitionTable: SaveSegments di, bx setDS cs setES cs push dx xor ax, ax call DiskFunctionsWithRetry jc ReadPartitionTable_12 pop dx mov ax, 0201h mov bx, offset RxDOSBIOS_DiskBuffer call DiskFunctionsWithRetry jc ReadPartitionTable_12 mov si, offset RxDOSBIOS_DiskBuffer + sizeSector - 2 - sizePARTITIONTABLE mov ax, word ptr [ RxDOSBIOS_DiskBuffer + sizeSector - 2 ] cmp ax, RxDOS_PARTITIONSIGNATURE clc ReadPartitionTable_12: RestoreSegments bx, di ret ;'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''; ; Disk Functions ; ;...............................................................; DiskFunctions: push bp int 13h pop bp ; call SetDiskError ret ;'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''; ; Disk Functions ; ;...............................................................; DiskFunctionsWithRetry: Entry def _retries, 03 def _errorcode def _drive, dx def _function, ax DiskFctRetry_08: push bp int 13h pop bp jnc DiskFctRetry_12 push bp mov byte ptr [ _errorcode ][ bp ], ah mov ah, 00h mov dl, byte ptr [ _drive ][ bp ] int 13h pop bp mov ax, word ptr [ _function ][ bp ] dec word ptr [ _retries ][ bp ] jnz DiskFctRetry_08 mov ah, byte ptr [ _errorcode ][ bp ] stc DiskFctRetry_12: Return ;'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''; ; Disk Functions ; ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -; ; ; ; AX contains BIOS error status ; ;...............................................................; setPacketReqError: Entry 2 darg _packet jnc setPacketReqError_08 ; if not an error --> pushf push ds push bx call convertErrorCodefromBIOSStatus getdarg ds, bx, _packet mov word ptr [ rhStatus ][ bx ], ax ; set error flag pop bx pop ds popf setPacketReqError_08: Return ;'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''; ; Error Trap Functions ; ;...............................................................; SetInvalidDriveError: Entry 2 darg _packet jnc SetInvalidDriveError_08 pushf push ds push bx getdarg ds, bx, _packet mov word ptr [ rhStatus ][ bx ], devErrUnknownUnit + OP_ERROR pop bx pop ds popf SetInvalidDriveError_08: Return ;'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''; ; Disk Functions ; ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -; ; ; ; AX contains BIOS error status ; ;...............................................................; convertErrorCodefromBIOSStatus: xor bx, bx mov bl, ah ; BIOS error code to index register mov ax, devErrDeviceNotReady cmp bx, dskErrDriveTimeOut jz convErr_08 cmp bx, dskErrDriveNotReady jz convErr_08 xor ax, ax cmp bx, Max_BIOSErrorCodeTable jnc convErr_08 mov al, byte ptr cs:[ BIOSErrorCodeTable ][ bx ] convErr_08: or ax, OP_ERROR ret BIOSErrorCodeTable: db 0 ; 0 - dskErrNoError db devErrBadDriveReq ; 1 - dskErrInvalidParameter db devErrBadDriveReq ; 2 - dskErrAddrMarkNotFound db devErrWriteProtectViol ; 3 - dskErrWriteProtected db devErrSectorNotFound ; 4 - dskErrSectorNotFound db devErrGeneralFailure ; 5 - dskErrResetFailed db devErrGeneralFailure ; 6 - dskErrDisketteRemoved db devErrGeneralFailure ; 7 - dskErrBadParameterTable db devErrGeneralFailure ; 8 - dskErrDMAOverrun db devErrGeneralFailure ; 9 - dskErrCross64kBoundary db devErrGeneralFailure ; 10 - dskErrBadSector db devErrGeneralFailure ; 11 - dskErrBadCylinder db devErrGeneralFailure ; 12 - dskErrMediaTypeNotFound db devErrGeneralFailure ; 13 - dskErrInvalidNumSectors db devErrGeneralFailure ; 14 - dskErrControlAddrMark db devErrGeneralFailure ; 15 - dskErrDMAArbOutOfRange db devErrCRCerr ; 16 - dskErrCRCerror db devErrCRCerr ; 17 - dskErrECCCorrectedErr Max_BIOSErrorCodeTable equ ($ - BIOSErrorCodeTable - 1) ;'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''; ; Reallocated Space ; ;...............................................................; RxDOSBIOS_DiskBuffer: db sizeSector dup(?) ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ; The address remains valid but the contents are destroyed ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - RxDOSBIOS_LastAddress: RxDOS_StartBlockedDeviceTable: ; anything allocated after this line will either be clobbered or ; reallocated ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ; this message is destroyed once the device table is initialized ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - RxDOSBIOS ENDS END RxDOSBIOS_Start