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                                  ; Copy video bios to data segment
    11                                  ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
    12                                  
    13 00000000 8CCD                    	mov	bp, cs
    14 00000002 81C50010                	add	bp, 1000h
    15 00000006 06                      	push	es
    16 00000007 1E                      	push	ds
    17 00000008 8EC5                    	mov	es, bp
    18 0000000A 31FF                    	xor	di, di
    19 0000000C BE00C0                  	mov	si, 0C000h
    20 0000000F 8EDE                    	mov	ds, si
    21 00000011 31F6                    	xor	si, si
    22 00000013 B90080                  	mov	cx, 32768
    23 00000016 F3A5                    	rep	movsw
    24 00000018 1F                      	pop	ds
    25 00000019 07                      	pop	es
    26                                  
    27                                  ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
    28                                  ; Create video bios image file
    29                                  ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
    30                                  		
    31 0000001A BA[7F00]                	mov	dx, img_file_name
    32                                  	;mov	cx, 0 ; File Attributes
    33 0000001D B43C                    	mov	ah, 3Ch ; MS-DOS Function = Create File
    34 0000001F CD21                    	int	21h
    35 00000021 7311                    	jnc	short cvb_2
    36                                  cvb_0:
    37 00000023 BE[8C00]                	mov	si, Msg_Error
    38                                  cvb_1:
    39 00000026 E84500                  	call	print_msg
    40                                  
    41 00000029 BE[B800]                	mov	si, CRLF
    42 0000002C E83F00                  	call	print_msg
    43 0000002F B8004C                  	mov	ax, 4C00h		; terminate
    44 00000032 CD21                    	int	21h
    45                                  
    46                                  cvb_2:
    47 00000034 BE[B800]                	mov	si, CRLF
    48 00000037 E83400                  	call	print_msg
    49                                  
    50                                  ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
    51                                  ; Open image file for writing
    52                                  ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
    53                                  
    54 0000003A B002                    	mov	al, 2 ; open for reading and writing
    55                                  	;mov	dx, img_file_name
    56 0000003C B43D                    	mov	ah, 3Dh ; open file
    57 0000003E CD21                    	int	21h
    58 00000040 72E1                    	jc	short cvb_0
    59                                  
    60 00000042 A3[7D00]                	mov	[img_file_handle], ax
    61                                  
    62 00000045 BE[9700]                	mov	si, Msg_Writing_Bios_Image
    63 00000048 E82300                  	call	print_msg
    64                                  
    65 0000004B 1E                      	push	ds
    66 0000004C 8B1E[7D00]              	mov	bx, [img_file_handle]
    67 00000050 8EDD                    	mov	ds, bp ; Video bios copy segment
    68 00000052 31D2                    	xor	dx, dx	
    69 00000054 B90080                  	mov	cx, 32768
    70 00000057 B440                    	mov	ah, 40h ; write to file	
    71 00000059 CD21                    	int	21h
    72 0000005B 7303                    	jnc	short cvb_4
    73                                  cvb_3:
    74 0000005D 1F                      	pop	ds
    75 0000005E EBC3                    	jmp	short cvb_0
    76                                  cvb_4:	
    77                                  	;mov	bx, [cs:img_file_handle]
    78                                  	;mov	cx, 32768
    79 00000060 01CA                    	add	dx, cx ; + 32768	
    80 00000062 B440                    	mov	ah, 40h ; write to file	
    81 00000064 CD21                    	int	21h
    82                                  	;pop	ds
    83                                  	;jc	short cvb_0
    84 00000066 72F5                    	jc	short cvb_3
    85                                  
    86 00000068 1F                      	pop	ds
    87                                  
    88 00000069 BE[B300]                	mov	si, Msg_OK
    89 0000006C EBB8                    	jmp	short cvb_1
    90                                  
    91                                  ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
    92                                  ; Print messages
    93                                  ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
    94                                  
    95                                  print_msg:
    96                                  
    97                                  print_msg_LOOP:
    98 0000006E AC                      	lodsb                           ; Load byte at DS:SI to AL
    99 0000006F 20C0                    	and     al, al            
   100 00000071 7409                    	jz      short print_msg_OK       
   101 00000073 B40E                    	mov	ah, 0Eh			
   102 00000075 BB0700                  	mov     bx, 07h             
   103 00000078 CD10                    	int	10h			; BIOS Service func ( ah ) = 0Eh
   104                                  					; Write char as TTY
   105                                  					; AL-char BH-page BL-color
   106 0000007A EBF2                    	jmp     short print_msg_LOOP           
   107                                  
   108                                  print_msg_OK:
   109 0000007C C3                      	retn
   110                                  
   111                                  ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
   112                                  ; Data
   113                                  ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
   114                                  
   115                                  img_file_handle:
   116 0000007D 0000                    	dw	0
   117                                  img_file_name:
   118 0000007F 5642494F5336344B2E-     	db	'VBIOS64K.BIN'
   119 00000088 42494E             
   120 0000008B 00                      	db 	0
   121                                  
   122                                  ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
   123                                  ; Messages
   124                                  ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
   125                                  
   126                                  Msg_Error:
   127 0000008C 0D0A                    	db	0Dh, 0Ah
   128 0000008E 4572726F72202120        	db	'Error ! '
   129 00000096 00                      	db	0
   130                                  
   131                                  Msg_Writing_Bios_Image:
   132 00000097 57726974696E672056-     	db	"Writing Video BIOS image...", 0
   133 000000A0 6964656F2042494F53-
   134 000000A9 20696D6167652E2E2E-
   135 000000B2 00                 
   136                                  Msg_OK:
   137 000000B3 204F4B2E                	db	' OK.'
   138 000000B7 00                      	db	0
   139                                  CRLF:
   140 000000B8 0D0A                    	db	0Dh, 0Ah
   141 000000BA 00                      	db	0
   142                                  Signature:
   143 000000BB 4572646F67616E2054-     	db	'Erdogan Tan - 28/11/2018'
   144 000000C4 616E202D2032382F31-
   145 000000CD 312F32303138       
   146 000000D3 00                      	db	0