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Assembly Source File | 1992-08-27 | 17.6 KB | 722 lines

; Hobbes ; Mode X Library ; Copyright (C) 1992 Court Demas -- cd2a+@cmu.edu ; Portions Copyright (C) 1992 Steven Dollins -- sdollins@uiuc.edu include hobbes.inc ;---------------------------------------------------------------------------- ; Thanks: ; ; Michael Abrash - ; the almight one ; ; Steve Dollins - ; Line, Triangle, Text, Palette code ; ; Sutty & Blair - ; Cool EGA/VGA Book ; Panning/Scrolling/Split Screen routines, etc. ; ; Frederick J. Haab - ; "Scroll" func for viewing virtual screen ; ;---------------------------------------------------------------------------- .DATA public _RowOffset _RowOffset dw 1024 dup(?) public _ClipLeft, _ClipTop, _ClipRight, _ClipBottom _ClipLeft dw 0 _ClipTop dw 0 _ClipRight dw 4Fh _ClipBottom dw 3Fh ;Ok, this is a bit much (maybe), but it's the only decent way I know of to ;handle all of the different possible memory arrangements. It has to handle ;different resolutions, split screens, virtual screens, double-buffering, ;etc. If you have a better idea, do tell. public _ModeX_Segment, _Draw_Offset, _Display_Offset _ModeX_Segment dw 0A000h _Draw_Offset dw 00000h _Display_Offset dw 00000h public _Split_Line, _Split_Offset, _Page0_Offset, _Page1_Offset _Split_Line dw 240d _Split_Offset dw 00000h ;always 0 _Page0_Offset dw 00000h _Page1_Offset dw 04b00h public _Physical_Width_Addr, _Physical_Height_Addr public _Physical_Width_Pix, _Physical_Height_Pix _Physical_Width_Addr dw 80d _Physical_Height_Addr dw 60d _Physical_Width_Pix dw 320d _Physical_Height_Pix dw 240d public _Virtual_Width_Addr, _Virtual_Height_Addr public _Virtual_Width_Pix, _Virtual_Height_Pix, _Virtual_Size _Virtual_Width_Addr dw 80d _Virtual_Height_Addr dw 60d _Virtual_Width_Pix dw 320d _Virtual_Height_Pix dw 240d _Virtual_Size dw 04b00h public _Background_Offset, _Bitmap_Offset, _Pattern_Offset _Background_Offset dw 09600h _Bitmap_Offset dw 0f000h _Pattern_Offset dw 0fffch public _Double_Buffer, _Current_Page _Double_Buffer dw 1 ;double-buffer by default _Current_Page dw 0 extrn _MouseSetPage ;---------------------------------------------------------------------------- ; Index/data pairs for CRT Controller registers that differ between ; mode 13h and mode X. CRTParms label word dw 00d06h ;vertical total dw 03e07h ;overflow (bit 8 of vertical counts) dw 04109h ;cell height (2 to double-scan) dw 0ea10h ;v sync start dw 0ac11h ;v sync end and protect cr0-cr7 dw 0df12h ;vertical displayed dw 00014h ;turn off dword mode dw 0e715h ;v blank start dw 00616h ;v blank end dw 0e317h ;turn on byte mode CRT_PARM_LENGTH equ (($-CRTParms)/2) .CODE ;---------------------------------------------------------------------------- ; void Set320x200Mode(void); ; public _Set320x200Mode _Set320x200Mode proc push bp mov bp,sp push ds mov ax,@data mov ds,ax mov ax,320d mov _Physical_Width_Pix,ax mov ax,200d mov _Physical_Height_Pix,ax mov _Split_Line,ax mov ax,80d mov _Physical_Width_Addr,ax mov ax,50d mov _Physical_Height_Addr,ax mov ah,0 mov al,BYTE PTR [bp+6] mov bl,al and bl,07fh @@setxmode: mov ah,0 ; set 256-color mode mov al,13h int 10h mov dx,03c4h ; convert to X-mode addressing mov ax,0604h ; chain mode off out dx,ax mov dx,03d4h mov ax,0014h ; doubleword off out dx,ax mov ax,0E317h ; byte mode on out dx,ax mov dx,03CEH mov ax,0FF08h ; all CPU data bits out dx,ax mov dx,03c4h ; prepare plane mask reg. for access mov ax,0f02h out dx,al mov ax,WORD PTR[bp+6] test al,080h jnz @@dontclear mov ax,0f02h out dx,ax ; clear all planes at once mov ax,0a000h mov es,ax xor di,di mov cx,0ffffh xor ax,ax rep stosb @@dontclear: pop ds pop bp ret _Set320x200Mode endp ;---------------------------------------------------------------------------- ; void Set320x240(void); ; public _Set320x240Mode _Set320x240Mode proc push ds mov ax,@data mov ds,ax push bp push si push di mov ax,320d mov _Physical_Width_Pix,ax mov ax,240d mov _Physical_Height_Pix,ax mov _Split_Line,ax mov ax,80d mov _Physical_Width_Addr,ax mov ax,60d mov _Physical_Height_Addr,ax mov ax,13h ;let the BIOS set standard 256-color int 10h ; mode (320x200 linear) mov dx,SC_INDEX mov ax,0604h out dx,ax ;disable chain4 mode mov ax,0100h out dx,ax ;synchronous reset while switching clocks mov dx,MISC_OUTPUT mov al,0e3h out dx,al ;select 25 MHz dot clock & 60 Hz scanning rate mov dx,SC_INDEX mov ax,0300h out dx,ax ;undo reset (restart sequencer) mov dx,CRTC_INDEX ;reprogram the CRT Controller mov al,11h ;VSync End reg contains register write out dx,al ; protect bit inc dx ;CRT Controller Data register in al,dx ;get current VSync End register setting and al,7fh ;remove write protect on various out dx,al ; CRTC registers dec dx ;CRT Controller Index cld mov si,offset CRTParms ;point to CRT parameter table mov cx,CRT_PARM_LENGTH ;# of table entries @@SetCRTParmsLoop: lodsw ;get the next CRT Index/Data pair out dx,ax ;set the next CRT Index/Data pair loop @@SetCRTParmsLoop mov dx,SC_INDEX mov ax,0f02h out dx,ax ;enable writes to all four planes mov ax,_ModeX_Segment ;now clear all display memory, 8 pixels mov es,ax ; at a time sub di,di ;point ES:DI to display memory sub ax,ax ;clear to zero-value pixels mov cx,8000h ;# of words in display memory rep stosw ;clear all of display memory pop di pop si pop bp pop ds ret _Set320x240Mode endp ;---------------------------------------------------------------------------- ; void Set320x400(void); ; public _Set320x400Mode _Set320x400Mode proc far mov ax,320d mov _Physical_Width_Pix,ax mov ax,400d mov _Physical_Height_Pix,ax mov _Split_Line,ax mov ax,80d mov _Physical_Width_Addr,ax mov ax,100d mov _Physical_Height_Addr,ax mov ax,13h int 10h mov dx,SC_INDEX mov al,MEMORY_MODE out dx,al inc dx in al,dx and al,not 08h or al,04h out dx,al mov dx,GC_INDEX mov al,GRAPHICS_MODE out dx,al inc dx in al,dx and al,not 10h out dx,al dec dx mov al,MISCELLANEOUS out dx,al inc dx in al,dx and al,not 02h out dx,al ;CONST_TO_INDEXED_REGISTER SC_INDEX, MAP_MASK, 0fh mov dx,SC_INDEX mov ax,111100000000b + MAP_MASK out dx,al ;*** 1111 mov ax,_ModeX_Segment mov es,ax sub di,di mov ax,di mov cx,8000h cld rep stosw mov dx,CRTC_INDEX mov al,MAX_SCAN_LINE out dx,al inc dx in al,dx and al,not 1fh out dx,al dec dx mov al,UNDERLINE out dx,al inc dx in al,dx and al,not 40h out dx,al dec dx mov al,MODE_CONTROL out dx,al inc dx in al,dx or al,40h out dx,al ret _Set320x400Mode endp ;---------------------------------------------------------------------------- ; void _Set360x480Mode() ; .code vptbl dw 06b00h ; horz total dw 05901h ; horz displayed dw 05a02h ; start horz blanking dw 08e03h ; end horz blanking dw 05e04h ; start h sync dw 08a05h ; end h sync dw 00d06h ; vertical total dw 03e07h ; overflow dw 04009h ; cell height dw 0ea10h ; v sync start dw 0ac11h ; v sync end and protect cr0-cr7 dw 0df12h ; vertical displayed dw 02d13h ; offset dw 00014h ; turn off dword mode dw 0e715h ; v blank start dw 00616h ; v blank end dw 0e317h ; turn on byte mode vpend label word public _Set360x480Mode _Set360x480Mode proc push ds mov ax,cs mov ds,ax push ds mov ax,@data mov ds,ax mov ax,360d mov _Physical_Width_Pix,ax mov ax,480d mov _Physical_Height_Pix,ax mov _Split_Line,ax mov ax,90d mov _Physical_Width_Addr,ax mov ax,120d mov _Physical_Height_Addr,ax pop ds mov ax,13h ; start with standard mode 13h int 10h ; let the bios set the mode mov dx,3c4h ; alter sequencer registers mov ax,0604h ; disable chain 4 out dx,ax mov ax,0f02h ; set write plane mask to all bit planes out dx,ax push di xor di,di mov ax,0a000h ; screen starts at segment A000 mov es,ax mov cx,21600 ; ((XSIZE*YSIZE)/(4 planes))/(2 bytes per word) xor ax,ax cld rep stosw ; clear the whole of the screen pop di mov ax,0100h ; synchronous reset out dx,ax ; asserted mov dx,3c2h ; misc output mov al,0e7h ; use 28 mHz dot clock out dx,al ; select it mov dx,3c4h ; sequencer again mov ax,0300h ; restart sequencer out dx,ax ; running again mov dx,3d4h ; alter crtc registers mov al,11h ; cr11 out dx,al ; current value inc dx ; point to data in al,dx ; get cr11 value and al,7fh ; remove cr0 -> cr7 out dx,al ; write protect dec dx ; point to index cld mov si,offset vptbl mov cx,((offset vpend)-(offset vptbl)) shr 1 @@outlp: lodsw out dx,ax loop @@outlp pop ds ret _Set360x480Mode endp ;---------------------------------------------------------------------------- ; void _WaitForRetrace(void) ; public _WaitForRetrace _WaitForRetrace proc mov dx,03dah @@swap_retr1: in al,dx test al,8 jnz @@swap_retr1 @@swap_retr2: in al,dx test al,8 jz @@swap_retr2 ret _WaitForRetrace endp ;---------------------------------------------------------------------------- ; void SetClipPort(int LEFT, int TOP, int RIGHT, int Bottom) ; public _SetClipPort _SetClipPort proc ARG LEFT:WORD, TOP:WORD, RIGHT:WORD, BOTTOM:WORD push bp mov bp,sp push ds mov ax,@data mov ds,ax mov ax,LEFT mov _ClipLeft,ax mov ax,TOP mov _ClipTop,ax mov ax,RIGHT mov _ClipRight,ax mov ax,BOTTOM mov _ClipBottom,ax pop ds pop bp ret _SetClipPort endp ;---------------------------------------------------------------------------- ; void ShowPage( VRAM_PTR startoffset ) ; public _ShowPage _ShowPage proc ARG StartOffsetHigh:BYTE:1, StartOffsetLow:BYTE:1 push bp mov bp,sp push ds mov ax,@data mov ds,ax ; Wait for display enable to be active (status is active low), to be ; sure both halves of the start address will take in the same frame. mov bl,START_ADDRESS_LOW ;preload for fastest mov bh,StartOffsetLow ; flipping once display mov cl,START_ADDRESS_HIGH ; enable is detected mov ch,StartOffsetHigh mov dx,INPUT_STATUS_1 @@WaitDE: in al,dx test al,01h jnz @@WaitDE ;display enable is active low (0 = active) ; Set the start offset in display memory of the page to display. mov dx,CRTC_INDEX mov ax,bx out dx,ax ;start address low mov ax,cx out dx,ax ;start address high ; Now wait for vertical sync, so the other page will be invisible when ; we start drawing to it. mov dx,INPUT_STATUS_1 @@WaitVS: in al,dx test al,08h jz @@WaitVS ;vertical sync is active high (1 = active) pop ds pop bp ret _ShowPage endp ;---------------------------------------------------------------------------- ; void SetDisplay(int x0, int y0); ; public _SetDisplay _SetDisplay proc far ARG x:word,y:word push bp mov bp,sp push ds mov ax,@data mov ds,ax mov ax,[_Virtual_Width_Addr] ; Calculate Offset increment mul [y] ; for Y add ax,_Display_Offset ; add it to Start offset add ax,[x] ; add the column offset for X mov bh,al ; setup CRTC start addr regs and ; values in word registers for mov ch,ah ; fast word outs @@StartAddrEntry: mov bl,START_ADDRESS_LOW mov cl,START_ADDRESS_HIGH call _WaitForRetrace mov dx,CRTC_INDEX mov ax,bx out dx,ax ;start address low mov ax,cx out dx,ax ;start address high pop ds pop bp ret _SetDisplay endp ;---------------------------------------------------------------------------- ; void SetSplit(unsigned int Addr); ; ; Mode X (320x240, 256 colors) Set 320x240 mode split screen starting row ; The split screen resides on the bottom half of the screen and has a ; starting address of A000:0000 ; ; C near-callable as: ; ; Updates _MainScrnOffset to reflect the existence of the split screen region ; ie -MainScrnOffset is set to the offset of the first pixel beyond the split ; screen region ; public _SetSplit _SetSplit proc far ARG Line:word push bp mov bp,sp ; set up stack frame push di mov ax,[Line] mov _Split_Line,ax mov bx,_Virtual_Height_Pix sub bx,ax mov di,ax shl di,1 mov di,word ptr _RowOffset[di] add _Page0_Offset,di add _Page1_Offset,di add _Display_Offset,di add _Draw_Offset,di dec ax ; Don't ask me why. It works this way !! jns @@NotNeg ; Check that Split Scrn start scan line is +ve mov ax,0 ; Since -ve set to 0 @@NotNeg: push ax ; Save the decremented start scam line shl ax,1 ; Mode X is actually composed of 480 scan lines ; so for start scanline multiply required ModeX ; scan line by 2 mov [Line],ax ; save the scanline call _WaitForRetrace ; wait for vertical retrace mov dx,CRTC_INDEX mov ah,byte ptr [Line] mov al,LINE_COMPARE cli ; Dont allow register setting to be interrupted out dx,ax ; Bits 7-0 of the split screen scan line mov ah,byte ptr [Line+1] and ah,1 mov cl,4 shl ah,cl mov al,OVERFLOW ; Bit 4 of overflow register = Bit 8 of split out dx,al ; screen scan line, inc dx ; So using readability of VGA registers in al,dx ; Read the OVERFLOW register, and set the and al, not 10h ; bit corresponding to Bit 8 (above) or al,ah out dx,al dec dx mov ah,byte ptr [Line+1] and al,2 mov cl,3 ror ah,cl mov al,MAX_SCAN_LINE ; Bit 6 of max scan line register = out dx,al ; Bit 9 of split screen scan line inc dx ; As we did before, update the apropriate in al,dx ; bit without disturbing the rest and al, not 40h or al,ah out dx,al sti ; Registers are set, so interrupts are safe pop ax ; Determine where the first byte sub ax,_Physical_Height_Pix ;PHYSICAL_HEIGHT of the non split screen video ram neg ax ; starts and store it for future mov bx,_Virtual_Width_Addr ;[_ScrnLogicalByteWidth] ; reference mul bx mov _Draw_Offset,ax ; calculate no. non split screen rows in video ram mov cx,0ffffh ; cx = Maximum video ram offset sub cx,ax ; cx = cx - _MainScrnOfs xchg cx,ax ; swap cx and ax sub dx,dx ; DX:AX is divide operand, set DX = 0 div bx ; divide ax (prev cx) by ; ScrnLogicalByteWidth mov _Virtual_Height_Addr,ax ;[_ScrnLogicalHeight],ax ; Save Screen Logical Height sub ax,_Physical_Height_Pix ;PHYSICAL_HEIGHT Update the maximum Y position of ; mov [_MaxScrollY],ax ; Physical screen in logical screen xchg cx,ax ; restore original ax (MainScrnOfs) ; mov bh,al ; Set the visible screen start address ; mov ch,ah ; to the top left corner of the virtual ; jmp short StartAddrEntry ; screen pop di pop bp ret _SetSplit endp ;---------------------------------------------------------------------------- ; void FlipPage(void); ; ; SWAP(Display,Draw); ; Show(Display); ; extrn _MousePage_Offset public _FlipPage _FlipPage proc push ds mov ax,@data mov ds,ax mov cx,_Page0_Offset mov dx,_Page1_Offset cmp _Current_Page,0 je @@setpage1 @@setpage0: mov _Current_Page,0 mov _Display_Offset,cx mov _Draw_Offset,dx jmp short @@end @@setpage1: mov _Current_Page,1 mov _Display_Offset,dx mov _Draw_Offset,cx @@end: mov ax,_Draw_Offset mov _MousePage_Offset,ax mov ax,_Display_Offset ; call far ptr _MouseSetPage push ax call _ShowPage pop ax pop ds ret _FlipPage endp ;---------------------------------------------------------------------------- ; void RestoreTextMode( void ) public _RestoreTextMode _RestoreTextMode proc mov ax,0003h ; set text mode int 10h ret _RestoreTextMode endp ;---------------------------------------------------------------------------- END