1 ; **************************************************************************** 2 ; COPY VIDEO BIOS CODE - Erdogan Tan - 25/11/2018 3 ; **************************************************************************** 4 ; 28/11/2018 5 6 [BITS 16] 7 [ORG 100h] 8 9 ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 10 ; Check 'PMID' signature 11 ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 12 13 00000000 06 push es 14 00000001 BF00C0 mov di, 0C000h 15 00000004 8EC7 mov es, di 16 00000006 31FF xor di, di 17 00000008 B9ED7F mov cx, 32749 18 cvb_6: 19 0000000B B050 mov al, 'P' 20 0000000D F2AE repne scasb 21 0000000F E370 jcxz cvb_4 22 23 00000011 B04D mov al, 'M' 24 00000013 AE scasb 25 00000014 75F5 jne short cvb_6 26 00000016 B049 mov al, 'I' 27 00000018 AE scasb 28 00000019 75F0 jne short cvb_6 29 0000001B B044 mov al, 'D' 30 0000001D AE scasb 31 0000001E 75EB jne short cvb_6 32 00000020 07 pop es 33 34 ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 35 ; Copy video bios to data segment 36 ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 37 38 00000021 8CCD mov bp, cs 39 00000023 81C50010 add bp, 1000h 40 00000027 06 push es 41 00000028 1E push ds 42 00000029 8EC5 mov es, bp 43 0000002B 31FF xor di, di 44 0000002D BE00C0 mov si, 0C000h 45 00000030 8EDE mov ds, si 46 00000032 31F6 xor si, si 47 00000034 B90080 mov cx, 32768 48 00000037 F3A5 rep movsw 49 00000039 1F pop ds 50 0000003A 07 pop es 51 52 ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 53 ; Create video bios image file 54 ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 55 56 0000003B BA[AC00] mov dx, img_file_name 57 ;mov cx, 0 ; File Attributes 58 0000003E B43C mov ah, 3Ch ; MS-DOS Function = Create File 59 00000040 CD21 int 21h 60 00000042 7311 jnc short cvb_2 61 cvb_0: 62 00000044 BE[B900] mov si, Msg_Error 63 cvb_1: 64 00000047 E85100 call print_msg 65 66 0000004A BE[FF00] mov si, CRLF 67 0000004D E84B00 call print_msg 68 00000050 B8004C mov ax, 4C00h ; terminate 69 00000053 CD21 int 21h 70 71 cvb_2: 72 00000055 BE[FF00] mov si, CRLF 73 00000058 E84000 call print_msg 74 75 ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 76 ; Open image file for writing 77 ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 78 79 0000005B B002 mov al, 2 ; open for reading and writing 80 ;mov dx, img_file_name 81 0000005D B43D mov ah, 3Dh ; open file 82 0000005F CD21 int 21h 83 00000061 72E1 jc short cvb_0 84 85 00000063 A3[AA00] mov [img_file_handle], ax 86 87 00000066 BE[DE00] mov si, Msg_Writing_Bios_Image 88 00000069 E82F00 call print_msg 89 90 0000006C 1E push ds 91 0000006D 8B1E[AA00] mov bx, [img_file_handle] 92 00000071 8EDD mov ds, bp ; Video bios copy segment 93 00000073 31D2 xor dx, dx 94 00000075 B90080 mov cx, 32768 95 00000078 B440 mov ah, 40h ; write to file 96 0000007A CD21 int 21h 97 0000007C 730F jnc short cvb_5 98 cvb_3: 99 0000007E 1F pop ds 100 0000007F EBC3 jmp short cvb_0 101 cvb_4: 102 00000081 07 pop es 103 00000082 BE[B900] mov si,Msg_Error 104 00000085 E81300 call print_msg 105 00000088 BE[C400] mov si,Msg_PMID_not_found 106 0000008B EBBA jmp short cvb_1 107 cvb_5: 108 ;mov bx, [cs:img_file_handle] 109 ;mov cx, 32768 110 0000008D 01CA add dx, cx ; + 32768 111 0000008F B440 mov ah, 40h ; write to file 112 00000091 CD21 int 21h 113 ;pop ds 114 ;jc short cvb_0 115 00000093 72E9 jc short cvb_3 116 117 00000095 1F pop ds 118 119 00000096 BE[FA00] mov si, Msg_OK 120 00000099 EBAC jmp short cvb_1 121 122 ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 123 ; Print messages 124 ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 125 126 print_msg: 127 128 print_msg_LOOP: 129 0000009B AC lodsb ; Load byte at DS:SI to AL 130 0000009C 20C0 and al, al 131 0000009E 7409 jz short print_msg_OK 132 000000A0 B40E mov ah, 0Eh 133 000000A2 BB0700 mov bx, 07h 134 000000A5 CD10 int 10h ; BIOS Service func ( ah ) = 0Eh 135 ; Write char as TTY 136 ; AL-char BH-page BL-color 137 000000A7 EBF2 jmp short print_msg_LOOP 138 139 print_msg_OK: 140 000000A9 C3 retn 141 142 ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 143 ; Data 144 ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 145 146 img_file_handle: 147 000000AA 0000 dw 0 148 img_file_name: 149 000000AC 5642494F5336344B2E- db 'VBIOS64K.BIN' 150 000000B5 42494E 151 000000B8 00 db 0 152 153 ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 154 ; Messages 155 ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 156 157 Msg_Error: 158 000000B9 0D0A db 0Dh, 0Ah 159 000000BB 4572726F72202120 db 'Error ! ' 160 000000C3 00 db 0 161 Msg_PMID_not_found: 162 000000C4 504D4944207369676E- db 'PMID signature not found!',0 163 000000CD 6174757265206E6F74- 164 000000D6 20666F756E642100 165 Msg_Writing_Bios_Image: 166 000000DE 57726974696E672056- db 'Writing Video BIOS image...', 0 167 000000E7 6964656F2042494F53- 168 000000F0 20696D6167652E2E2E- 169 000000F9 00 170 Msg_OK: 171 000000FA 204F4B2E db ' OK.' 172 000000FE 00 db 0 173 CRLF: 174 000000FF 0D0A db 0Dh, 0Ah 175 00000101 00 db 0 176 Signature: 177 00000102 4572646F67616E2054- db 'Erdogan Tan - 28/11/2018' 178 0000010B 616E202D2032382F31- 179 00000114 312F32303138 180 0000011A 00 db 0