136 lines
2.3 KiB
NASM
136 lines
2.3 KiB
NASM
PUBLIC _enableUnchainedVGAMode
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PUBLIC _enableTextMode
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PUBLIC _fillScreen
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PUBLIC _latchCopyCube
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DISPLAY_MODE_VGA equ 13h
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DISPLAY_MODE_TEXT equ 03h
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VGA_SEQUENCE_CONTROLLER_INDEX equ 0x3c4
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VGA_SEQUENCE_CONTROLLER_DATA equ 0x3c5
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VGA_SEQUENCE_CONTROLLER_MEMORY_MODE equ 0x04
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VGA_SEQUENCE_CONTROLLER_MAP_MASK_MODE equ 0x02
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VGA_GRAPHICS_MODE_INDEX equ 0x3CE
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VGA_GRAPHICS_MODE equ 0x05
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VGA_CRT_CONTROLLER_INDEX equ 0x03d4
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VGA_CRT_CONTROLLER_DATA equ 0x03d5
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VGA_CRT_CONTROLLER_UNDERLINE_LOC equ 0x14
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VGA_CRT_CONTROLLER_MODE_CONTROL equ 0x17
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.386
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.model flat,c
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.CODE
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_enableUnchainedVGAMode:
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mov ax,0x0013;
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int 0x10
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mov dx, VGA_SEQUENCE_CONTROLLER_INDEX
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mov al, VGA_SEQUENCE_CONTROLLER_MEMORY_MODE
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mov ah, 0x06
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out dx, ax
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mov dx, VGA_CRT_CONTROLLER_INDEX
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mov al, VGA_CRT_CONTROLLER_MODE_CONTROL
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mov ah, 0xe3
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out dx, ax
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mov dx, VGA_CRT_CONTROLLER_INDEX
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mov al, VGA_CRT_CONTROLLER_UNDERLINE_LOC
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mov ah, 0x00
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out dx, ax
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ret
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_enableTextMode:
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mov ah,0h
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mov al,DISPLAY_MODE_TEXT
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int 10h
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ret
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_fillScreen:
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push ebp
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mov ebp, esp
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; set all bitplanes
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mov dx, VGA_SEQUENCE_CONTROLLER_INDEX
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mov al, 0x02
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mov ah, 0fh
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out dx, ax
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mov al, [ebp+8] ; requested color
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mov cx, 16000 ; loop index
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mov ebx, 0xa0000
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_fillScreen_loop:
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mov BYTE PTR [ebx], al
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inc ebx
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loop _fillScreen_loop
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mov esp,ebp
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pop ebp
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ret
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_latchCopyCube:
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push ebp
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mov ebp,esp
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; we need a y variable
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sub esp,4 ; y
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; enable latch reads
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mov dx, VGA_SEQUENCE_CONTROLLER_INDEX
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mov al, VGA_SEQUENCE_CONTROLLER_MAP_MASK_MODE
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mov ah, 0xf
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out dx, ax
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mov dx, VGA_GRAPHICS_MODE_INDEX
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mov al, 0x08
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mov ah, 0x00
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out dx, ax
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mov DWORD PTR [ebp-4],16
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; read across the cube, should take 4 * 16 reads
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mov cx,[ebp-4]
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_latchCopyCube_yLoop:
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mov [ebp-4],cx ; put y back in loop
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mov eax,[ebp-4] ; put y in eax
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dec eax ; offset by 1 for loop
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; can only multiply in eax by register
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mov bl,80
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mul bl ; number of lines
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add eax,0xa0000 ; vga base address
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; start x loop
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mov cx,4
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_latchCopyCube_xLoop:
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; fill latches via memory read
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mov bl, BYTE PTR [eax]
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; write blank
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mov [eax+12],0
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; increment vga pointer
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inc eax
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; loop until x is 0
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loop _latchCopyCube_xLoop
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; restore y for looping
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mov cx,[ebp-4]
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; loop until y is 0
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loop _latchCopyCube_yLoop
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; put things back
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mov esp,ebp
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pop ebp
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ret
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end
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