ProfitPress Mega CDROM2 Shareware Freeware (MSDOS)(1992)(Eng)

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/ ProfitPress Mega CDROM2 …eeware (MSDOS)(1992)(Eng) / ProfitPress-MegaCDROM2.B6I / MAGAZINE / MISC / PCTJ1188.ZIP / VGAZOOM2.ASM < prev

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Assembly Source File | 1988-09-14 | 15.4 KB | 353 lines

;******************************************************************** ; File VGAZOOM2 - 1280*400 VGA driver procedures ; Written by Arun Johary & Bo Ericsson, ; Chips & Technologies Inc. ; This file is not executable as stand-alone. ; After assembling, link it with VGAZOOM.OBJ, ; then convert to .COM with EXE2BIN. ; Resulting VGAZOOM.COM is a TSR for implementing 1280x480 mode, ; with zooming to/from 640X480 mode and panning. ;******************************************************************** LORES equ 0 HIRES equ 1 public DRAWCHR public SETMODE public HORIZ_SCROLL_4 public VERT_SCROLL public EndOfProgram code segment para public 'code' assume cs:code ;******************************************************************** SETMODE proc near ; This procedure programs the VGA registers for one of two ; modes depending on AX ; AX = HIRES -- high resolution 1280*400 monochrome mode ; AX = LORES -- 640*400 monochrome mode push cs ; DS = CS because parameter tables pop ds ; are in the current segment cld ; clear for subsequent auto increment cmp ax, HIRES ; Hires mode ? jne SetMode01 ; if no, test for LORES mode lea bx, HTABLE ;HIRES table selected jmp SetTheMode ;program the parameters SetMode01: ;Test for LORES mode cmp ax, LORES ;LORES mode ? jne SetMode_End1 ;invalid parameter, return to caller lea bx, LTABLE ;lores table selected jmp SetTheMode ;program the parameters SetMode_End1: jmp SetMode_End SetTheMode: ;Sync reset while programming mode mov dx, 3C4H ;sequencer address mov ax, 0200h ;sync. reset out dx, ax ;write the register ;Set miscellaneous output register mov dx, 3C2H ;miscllaneous output register address mov al, [bx+9] ;table value for Misc Output Register. out dx, al ;write the register ;Set sequencer registers 01-04 mov dx, 3C4H ;sequencer address mov cx, 4 ;4 registers to write mov ah, 1 ;start with register 1 mov si, bx ;beginning of parameter table add si, 5 ;point to sequencer params in table call W_IndexRegs ;program the registers ;Get out of synchronous reset mov dx, 3C4H ;sequencer address mov ax, 0300h ;out of reset mode out dx, ax ;write register ;Unprotect CRT controller mov dx, 3D4H ;crtc address mov ax, 011h ;vertical sync end register out dx, ax ;set protect bit (D7) to 0 ;Set CRT controller registers 00-18 mov cx, 25 ;25 registers to write xor ah, ah ;start with CRTC register 0 mov si, bx ;beginning of parameter table add si, 10 ;point to CRTC parameters in the table call W_IndexRegs ;program the registers ;Set Graphics controller regs 00-08 mov dx, 3CEH ;graphics ctrl address mov cx, 9 ;9 registers to write xor ah, ah ;start with GC register 0 mov si, bx ;beginning of parameter table add si, 55 ;point to GC parameter in the table call W_IndexRegs ;program the registers ;Set Attribute controller regs 00-14 mov dx, 3DAH ;Status register address in al, dx ;reset attribute flip-flop mov dx, 3c0h ;attribute ctrl address mov cx, 20 ;20 registers to write xor ah, ah ;start with register 0 mov si, bx ;beginning of parameter table add si, 35 ;point to Attr. Ctrl params in table call W_Attr_Regs ;program the registers mov al, 14h ;write to Attribute color select reg out dx, al ;(not stored in parameter table) xor al, al ;data = 0 out dx, al ;write data mov al, 20h ;reenable video out dx, al ;write the index reg to reenable video ;Set external palette mov dx, 3C6H ;Palette mask register mov al, 0ffh ;enable all 8 bits out dx, al ;write the mask mov dx, 3C8H ;Palette address register lea si,[bx+64] ;point to palette parms in table xor ah,ah ;start at palette reg 0 mov cx,4 ;set 4 colors call W_Palette ;program the palette registers SetMode_End: ;end of this procedure ret ;******************************************************************** ; These two tables provide parameters for programming VGA hardware ; in each of two modes. HTABLE label byte ; parameter table for 1280*400 mono mode db 000h, 000h, 000h, 000h, 000h ; Dymmy header db 005h, 00Fh, 000h, 00eh ; Sequencer offsets 01-04 db 063h ; Miscellaneous register ; CRT Controller offsets 00-18h db 05Fh, 04Fh, 050h, 082h, 054h, 080h, 0bFh, 01Fh db 020h, 000h, 000h, 000h, 000h, 000h, 000h, 000h db 09ch, 00eh, 08Fh, 014h, 060h, 096h, 0b9h, 0abh, 0FFh ; Attribute Controller offsets 00-13h db 000h, 001h, 002h, 003h, 004h, 005h, 006h, 007h db 008h, 009h, 00ah, 00bh, 00ch, 00dh, 00eh, 00Fh db 001h, 000h, 003h, 000h ; Graphics Controller offsets 00-08 db 000h, 000h, 000h, 000h, 000h, 020h, 005h, 00Fh, 0FFh ; DAC Palette registers 0-3 db 000h, 000h, 000h ;reg 0: black db 01ah, 01ah, 01ah ;reg 1: grey db 01ah, 01ah, 01ah ;reg 2: grey db 02ah, 02ah, 02ah ;reg 3: white ;******************************************************************** LTABLE label byte ; parameter table for 640*400 mode db 000h, 000h, 000h, 000h, 000h ; Dymmy header db 011h, 00Fh, 000h, 00eh ; Sequencer offsets 01-04 db 063h ; Miscellaneous register ; CRT Controller offsets 00-18h db 05Fh, 050h, 052h, 0e2h, 054h, 0e0h, 0bFh, 01Fh db 000h, 000h, 000h, 000h, 000h, 000h, 000h, 000h db 09ch, 00eh, 08Fh, 014h, 060h, 096h, 0b9h, 0a3h, 0FFh ; Attribute Controller offsets 00-13h db 000h, 001h, 002h, 003h, 004h, 005h, 006h, 007h db 008h, 009h, 00ah, 00bh, 00ch, 00dh, 00eh, 00Fh db 001h, 000h, 001h, 000h ; Graphics Controller offsets 0-8 db 000h, 000h, 000h, 000h, 000h, 000h, 005h, 00Fh, 0FFh ; DAC Palette registers 0-3 db 000h, 000h, 000h ;reg 0: black db 02ah, 02ah, 02ah ;reg 1: white db 02ah, 02ah, 02ah ;reg 2: white db 02ah, 02ah, 02ah ;reg 3: white SETMODE endp ;******************************************************************** DRAWCHR proc near ; this procedure draws a character on the screen in the graphics ; mode; parameters are expected to be as follows: ; AL: -- char code ; BX: -- bit map width ; DX: -- font height (8 bits only) ; DS:SI -- Disp Mem pointer ; ES:DI -- Font pointer push cx ;save CX mov cx,dx ;get char height in CX mul dl ;AX gets font offset for character add di,ax ;ES:DI gets font address for font LABL0: mov ah,es:[di] ;read font pattern mov ds:[si],ah ;write into display memory inc di ;next line of font pattern add si,bx ;next line in display memory loop LABL0 ;repeat for every scan line pop cx ;retrieve CX ret DRAWCHR endp ;******************************************************************** W_INDEXREGS proc near ;This procedure reads a byte from the parameter table and then ;writes it to a index/data register. ; AH = index number of first register to receive parameter ; CX = # of index registers to be loaded ; DX -- I/O port address, ; DS:SI -- points to parameters lodsb ;load parameter from table into AL xchg al, ah ;get index in AL, data in AH out dx, ax ;write index/data register pair xchg al, ah ;get index in AH inc ah ;next index loop W_IndexRegs ;repeat ret W_INDEXREGS endp ;******************************************************************** W_ATTR_REGS proc near ;This procedure reads a byte from the parameter table and then ; writes it to a self index/data register. ; AH = index number of first register to receive parameter ; CX = # of index registers to be loaded ; DX -- I/O port address, ; DS:SI -- points to parameters xchg al, ah ;get index in AL out dx, al ;write index xchg al, ah ;get index in AH lodsb ;get data from table in AL out dx, al ;write data inc ah ;next index loop W_Attr_Regs ;repeat ret W_ATTR_REGS endp ;******************************************************************** W_PALETTE proc near ; This procedure reads a byte from the parameter table and then ; writes it to the G171 palette/DAC. DS:SI -- point to parameters, ; AH = starting index number, ; CX = # of index registers, ; DX -- I/O addr of DAC address reg, ; DS:SI pointer to data area mov al,ah ;get start index number out dx,al ;send it to address reg inc dx ;point to DAC data reg W_pal1: lodsb ;load data parameter out dx, al ;write red data lodsb ;load next data byte out dx, al ;write green data lodsb ;repeat w/blue data out dx, al loop W_Pal1 ;repeat w/next palette reg ret W_PALETTE endp ;******************************************************************** RD_INDEXREG proc near ;This procedure reads an indexed VGA register ; Input: AL = index number of register ; DX = I/O address of register ; Ouput: register contents returned in AL out dx,al ; write index inc dx ; point to data register in al,dx ; read data register dec dx ; point to index register ret RD_INDEXREG endp ;******************************************************************** VERT_SCROLL proc near ; This procedure scrolls the screen up or down by a specified number ; of lines; parameters are expected to be as follows: ; AX -- scroll count, # scan lines in 2's complement form, ; negative for scroll down ; BX -- bit map width imul bx ;AX = bytes to scroll mov bx,ax ;save start address change in BX mov dx,3d4h ; CRT address mov al,0ch ; start address high call Rd_IndexReg ;read register mov ah,al ;move to AH mov dx,3d4h ; CRT address mov al,0dh ; start address low call Rd_IndexReg ;read register add bx,ax ;add change to old start address mov ah,bh ;to get new start address, write the mov al,0ch ;high byte back to CRTC out dx,ax ;write new start address (HIGH) inc al ;point to start address LOW register mov ah,bl ;get lower byte of start address out dx,ax ;write new start address (LOW) ret VERT_SCROLL endp ;******************************************************************** HORIZ_SCROLL_4 proc near ; This procedure scrolls the screen left or right by a specified ; number of pixels. Parameters are expected to be as follows: ; AX -- scroll count, # pixels in 2's complement form, ; positive - scroll right, negative, scroll left. mov bx, ax ;save scroll count mov dx,3d4h ; CRT address mov al,0ch ; start address high call Rd_IndexReg ;read register mov ah,al ;move to AH mov dx,3d4h ; CRT address mov al,0dh ; start address low call Rd_IndexReg ;read register mov bp,ax ;save current start address mov dx,3d4h ; CRT address mov al,08h ; byte panning control call Rd_IndexReg ;read register mov cl,2 shr al,cl ;divide by 4 and al,18h ;retain bits D3 and D4 only mov ah,al ;save in ah mov dx,3DAH ;Status register address in al,dx ;reset attribute flip flop mov dx,3C0H ;address for attribute controller mov al,33h ;Panning Control out dx,al ;point to attribute panning register inc dx ;point to data register in al,dx ;read current byte panning control dec dx ;point back to Attr Ctrl address and al,7 ;retain bits D0-D2 add ah,al ;get old absolute panning control mov al,ah ;move to AL, 0 into AH xor ah,ah ;Absolute panning in AX add bx,ax ;compute new absolute panning mov ax,bx ;get it into AX and al,7 ;retain bits D0-D2 out dx,al ;write new attribute pan control mov ax,bx ;new absolute pan control in AX mov cl,2 shl ax,cl ;multiply by 4 mov ah,al ;save in AH and ah,60h ;retain bits D6-D5 mov dx,3D4H ;CRTC address mov al,8 ;index for byte panning control reg out dx,ax ;write new byte panning control mov cl,5 sar bx,cl ;start address adjust add bx,bp ;new start address mov ah,bh ;upper bits go into start address mov al,0ch ;Start Address high register index out dx,ax ;Write start address high inc al ;Start Address low index mov ah,bl ;low byte of start address out dx,ax ;Write start address low ret HORIZ_SCROLL_4 endp EndOfProgram label byte code ends end