World of Graphics/WOGRAPH.BIN/430.SVGA16.ASM

Assembly Source File | 1993-03-07 | 20KB | 700 lines

;****************************************************************************
;*
;*                           SuperVGA Test Library
;*
;*                  Copyright (C) 1993 Kendall Bennett.
;*                            All rights reserved.
;*
;* Filename:    $RCSfile: svga16.asm $
;* Version:        $Revision: 1.2 $
;*
;* Language:    80386 Assembler
;* Environment:    IBM PC (MS DOS)
;*
;* Description:    This source file contains code to initialise the SuperVGA
;*                for bank switching and extended page flipping.
;*
;*                It also contains code to draw pixels, clear the display
;*                and perform page flipping for SuperVGA 16 color video modes.
;*
;* $Id: svga16.asm 1.2 1993/03/07 04:05:36 kjb Exp $
;*
;* Revision History:
;* -----------------
;*
;* $Log: svga16.asm $
;* Revision 1.2  1993/03/07  04:05:36  kjb
;* Bug fixes.
;*
;* Revision 1.1  1993/03/03  10:25:25  kjb
;* Initial revision
;*
;****************************************************************************

        IDEAL
        JUMPS
        P386                    ; Use 386 instructions

INCLUDE "model.mac"                ; Memory model macros

header        svga16

INCLUDE    "MGRAPH.EQU"            ; Include Equates for Mgraph Routines

CRTC            EQU    3D4h        ; Port of CRTC registers
VGABufferSeg    EQU    0A000h        ; Segment of VGA display memory
FIRSTMODE        EQU    grEGA_320x200x16
MAXMODE            EQU    grSVGA_1280x1024x16

begcodeseg    svga16

; Globals used by driver

OldBIOSMode            db    0            ; Old video mode before graphics
Old50Lines            db    0            ; 1 if old mode was 50 line VGA
CntDriver            dw    0            ; Graphics driver number
CntMode                dw    0            ; Graphics mode number
CntChipID            dw    0            ; Graphics driver chip ID
CntColors            dw    gr16Color    ; This is a 16 color driver

; The following information held in the status status area changes depending
; on which mode the driver is set up to be used in:

StatusArea:

XRes                dw    0            ; Device resolution in x direction - 1
YRes                dw    0            ; Device resolution in y direction - 1
BytesPerLine        dw    0            ; Number of bytes in a line
PageSize            dd    0            ; Graphics page size

MaxPage                dw    0            ; Maximum number of video pages
OriginOffset        dw    0            ; Offset of 0,0 into buffer

; Here we set up a series of tables that can be used to fill in the start of
; the status area for each mode supported by this driver, and the address's
; of the routines required for each particular driver mode:

ModeTabStart:

ModeEGA_320x200x16    dw    319            ; XRes
                    dw    199            ; YRes
                    dw    40            ; BytesPerLine
ModeEGA_640x200x16    dw    639            ; XRes
                    dw    199            ; YRes
                    dw    80            ; BytesPerLine
ModeEGA_640x350x16    dw    639            ; XRes
                    dw    349            ; YRes
                    dw    80            ; BytesPerLine
ModeVGA_640x400x16    dw    639            ; XRes
                    dw    399            ; YRes
                    dw    80            ; BytesPerLine
ModeVGA_640x480x16    dw    639            ; XRes
                    dw    479            ; YRes
                    dw    80            ; BytesPerLine
ModeSVGA_800x600:    dw    799            ; XRes
                    dw    599            ; YRes
                    dw    100            ; BytesPerLine
ModeSVGA_1024x768:    dw    1023        ; XRes
                    dw    767            ; YRes
                    dw    128            ; BytesPerLine
ModeSVGA_1280x1024:    dw    1279        ; XRes
                    dw    1023        ; YRes
                    dw    160            ; BytesPerLine
ModeTabSize            =    ($-ModeSVGA_1280x1024)    ; Size of table in bytes

INCLUDE "SV_PORTS.ASM"
INCLUDE "SV_BANKS.ASM"
INCLUDE "SV_MODES.ASM"
INCLUDE "SV_PAGE.ASM"
INCLUDE "SV_MAXPG.ASM"

;----------------------------------------------------------------------------
; int _initSuperVGA(int driver,int chipID,int mode,int memory)
;----------------------------------------------------------------------------
; Routine to initialise the bank switching code for the SuperVGA, and setup
; internal tables of information about the video mode. If the video mode
; is not supported, we return -1.
;
; The value returned is a status number, where bit 0 represents extended
; page flipping is available, bit 1 that separate read/write banks are
; available.
;----------------------------------------------------------------------------
procstart    __initSuperVGA

        ARG        driver:WORD, ChipID:WORD, mode:WORD, memory:WORD

        enter    0,0
        push    si
        push    di

; Save the driver number and chip ID for later

        mov        ax,[ChipID]
        mov        [CntChipID],ax
        mov        ax,[driver]
        mov        [CntDriver],ax

; Load the Status area with info for the currently selected mode:

        mov        ax,[mode]
        mov        [CntMode],ax
        cmp        ax,MAXMODE            ; AX := desired mode
        jg        @@Invalid            ; invalid if greater than maximum
        cmp        ax,FIRSTMODE
        jl        @@Invalid            ; invalid if less than first mode
        cmp        ax,grVGA_640x480x16
        jle        @@ValidVGAMode
        cmp        ax,grSVGA_800x600x16
        jl        @@Invalid            ; Mode is invalid

        add        ax,grVGA_640x480x16 - grSVGA_800x600x16 + 1
        jmp        @@LoadValues

@@ValidVGAMode:
        sub        ax,FIRSTMODE

@@LoadValues:
        mov        cx,ModeTabSize        ; Put size of table into cx
        mul        cl                    ; AX := Mode * ModeTabSize
        mov        si,ax
        lea        si,[ModeTabStart + si]
        push    cs
        pop        es                    ; Set up es to point to code seg
        lea        di,[StatusArea]        ; DI := Start of status area

        cld
    rep    movs     [BYTE es:di],[BYTE es:si]

        mov        ax,[driver]
        mov        bx,[mode]
        call    loadSVGAMode        ; Load the SuperVGA video mode
        or        ax,ax
        jz        @@Invalid            ; Mode not supported on this adapter!

        mov        [maxpage],0            ; Clear maxpage variable
        call    SetupBanks            ; Setup SuperVGA bank switching
        call    [InitSVGA]            ; Initialise the SuperVGA
        call    SetupPaging            ; Setup SuperVGA page flipping
        mov        ax,0                ; Assume no paging available
        jc        @@NoFlip
        mov        ax,1                ; Flipping available

@@NoFlip:
        push    ax                    ; Save flag for later

; Determine the number of pages available for the mode and the video page
; size.

        xor        ebx,ebx
        mov        bx,[memory]
        or        ax,ax
        jnz        @@ExtendedFlip

        cmp        [mode],grSVGA_800x600x16
        jge        @@Done                ; Don't calculate for SVGA modes then
        mov        bx,256                ; Extended flipping not available

@@ExtendedFlip:
        shl        ebx,10                ; EBX := video memory in bytes
        mov        ax,[mode]
        call    numPages            ; Calculate the number of video pages
        dec        ax
        mov        [MaxPage],ax        ; Save maximum page number
        mov        [DWORD pageSize],ebx
        mov        [WORD bytesPerLine],cx

@@Done:
        pop        ax                    ; AX := extended page flipping flag
        mov        bx,[TwoBanks]
        shl        bx,1
        or        ax,bx                ; Set the two banks flag
        jmp        @@Exit

@@Invalid:
        mov        ax,-1                ; Return failure!

@@Exit:
        pop        di
        pop        si
        leave
        ret

procend        __initSuperVGA

;----------------------------------------------------------------------------
; int _setSuperVGAMode(void);
;----------------------------------------------------------------------------
; Routine sets the system into the SuperVGA graphics mode setup by the
; initSuperVGA routine. Note that this routine remembers if the EGA/VGA
; 43/50 line mode was set.
;
; If the video mode was not correctly set, we return false.
;----------------------------------------------------------------------------
procstart    __setSuperVGAMode

        push    bp                    ; INT 10h Kills this!!!
        push    si                    ; so save all regs...
        push    di
        push    ds

        mov        ah,0Fh                ; Get current video mode service
        int        10h
        mov        [OldBIOSMode],al    ; Save old video mode
        mov        [Old50Lines],0        ; Default to non-50 line mode

        mov        ax,1130h            ; AH := INT 10h function number
                                    ; AL := Get character gen information
        mov        bh,00                ; Get contents of INT 1Fh
        xor        dl,dl                ; Clear dl
        int        10h                    ; Determine number of lines (in dl)
        cmp        dl,49                ; 50 line mode?
        jne        @@SetMode            ; No, must have been 25 lines
        mov        [Old50Lines],1        ; Yes, 50 line mode was on

@@SetMode:
        mov        ax,[CntDriver]
        mov        bx,[CntMode]
        call    loadSVGAMode        ; AX,BX := correct values for mode
        int        10h                    ; Set the video mode

        mov        ax,40h
        mov        es,ax
        xor        ax,ax
        cmp        [BYTE es:49h],3        ; Mode is still text mode, did not set
        jbe        @@Exit

        call    [InitSVGA]            ; Initialise bank switching on SuperVGA's
        mov        ax,1                ; Mode was correctly set

@@Exit:
        pop        ds
        pop        di                    ; Restore regs
        pop        si
        pop        bp                    ; Restore bp (after INT 10 trashes it)
        ret

procend        __setSuperVGAMode

;----------------------------------------------------------------------------
; void restoreMode(void)
;----------------------------------------------------------------------------
; Routine restores the original video mode that was set before graphics mode
; was entered.
;----------------------------------------------------------------------------
procstart    _restoreMode

        push    bp                    ; INT 10h kills bp sometimes
        push    si                    ; Save all regs...
        push    di

        call    [ExitSVGA]            ; Uninitialise the SuperVGA

        mov        ah,0                ; Set video mode service
        mov        al,[OldBIOSMode]    ; Get old BIOS mode number
        int        10h                    ; Set the video mode

        cmp        [Old50Lines],0        ; Was 50 line mode set?
        je        @@Exit                ; No, don't set it up

; Load video BIOS 8x8 characters into alphanumeric character generator

        mov        ax,1112h            ; AH := INT 10h function number
                                    ; AL := 8x8 character set load
        mov        bl,0                ; BL := block to load
        int        10h                    ; load 8x8 characters into RAM

@@Exit:
        pop        di                    ; Restore regs
        pop        si
        pop        bp                    ; Restore bp
        ret

procend        _restoreMode

;----------------------------------------------------------------------------
; void _getVideoInfo(int *xres,int *yres,int *bytesperline,int *maxpage)
;----------------------------------------------------------------------------
; Returns information about the currently selected video mode. The video
; mode must have been set for this info to be entirely valid.
;----------------------------------------------------------------------------
procstart    __getVideoInfo

        ARG        _xres:DWORD, _yres:DWORD, _bytesperline:DWORD, _maxpage:DWORD

        enter    0,0

        les        bx,[_xres]
        mov        ax,[xres]
        mov        [es:bx],ax        ; Return the x resolution

        les        bx,[_yres]
        mov        ax,[yres]
        mov        [es:bx],ax        ; Return the y resolution

        les        bx,[_bytesperline]
        mov        ax,[bytesperline]
        mov        [es:bx],ax        ; Return the bytes per line value

        les        bx,[_maxpage]
        mov        ax,[maxpage]
        mov        [es:bx],ax        ; Return the maximum page number

        leave
        ret

procend        __getVideoInfo

;----------------------------------------------------------------------------
; void putPixel(int x,int y,int color)
;----------------------------------------------------------------------------
; Routine sets the value of a pixel in native VGA graphics modes.
;
; Entry:        x        -    X coordinate of pixel to draw
;                y        -    Y coordinate of pixel to draw
;                color    -    Color of pixel to draw
;
;----------------------------------------------------------------------------
procstart    _putPixel

        ARG        x:WORD, y:WORD, color:WORD

        push    bp                    ; Set up stack frame
        mov        bp,sp

; Compute the pixel's address in video buffer

        mov        ax,[y]
        mov        bx,[x]
        mul        [BytesPerLine]        ; DX:AX := y * BytesPerLine

        mov        cl,bl                ; CL := low-order byte of x

        shr        bx,3                ; BX := x/8
        add        bx,ax
        adc        dx,0                ; DX:BX := y*BytesPerLine + x/8
        add        bx,[OriginOffset]    ; DX:BX := byte offset in video buffer
        adc        dx,[BankOffset]

        cmp        dl,[BYTE CurBank]
        je        @@NoChange

        mov        ax,dx
        call    [NewBank]

@@NoChange:
        mov        ax,VGABufferSeg
        mov        es,ax                ; ES:BX := byte address of pixel

        mov        ah,1                ; AH := unshifted bit mask
        and        cl,7                ; CL := x & 7
        xor        cl,7                ; CL := # bits to shift left

; set Graphics Controller Bit Mask register

        shl        ah,cl                ; AH := bit mask in proper postion
        mov        dx,3CEh                ; GC address register port
        mov        al,8                ; AL := Bit Mask Register number
        out        dx,ax

; set Graphics Controller Mode register

        mov        ax,0205h            ; AL := Mode register number
                                    ; AH := Write mode 2 (bits 0,1)
                                    ;    Read mode 0 (bit 3)
        out        dx,ax

; set data rotate/Function Select register

        mov        ax,3                ; AL := Data Rotate/Func select reg #
        out        dx,ax

; set the pixel value

        mov        al,[es:bx]            ; latch one byte from each bit plane
        mov        ax,[color]            ; AL := pixel value
        mov        [es:bx],al            ; update all bit planes

; restore default Graphics Controller registers

        mov        ax,0FF08h            ; default bit mask
        out        dx,ax

        mov        ax,0005                ; default mode register
        out        dx,ax

        mov        ax,0003                ; default function select
        out        dx,ax

        pop        bp
        ret

procend        _putPixel

;----------------------------------------------------------------------------
; void clear(void)
;----------------------------------------------------------------------------
; Routine to clear the screen. Works even if the display contains more than
; one bank, so will work for 1024x768 and 1280x1024 video modes.
;----------------------------------------------------------------------------
procstart    _clear

        push    bp                    ; Set up stack frame
        mov        bp,sp
        push    si                    ; Save registers
        push    di

; Setup graphics controller

        mov        dx,3CEh                ; DX := Graphics Controller I/O port

        mov        ah,0                ; AH := Background color
        xor        al,al                ; AL := 0 (Set/Reset register number)
        out        dx,ax                ; load set/reset register

        mov        ax,0F01h            ; AH := 1111b (mask for Enable set/reset)
                                    ; AL := 1 (enable Set/reset reg number)
        out        dx,ax                ; load enable set/reset reg

        mov        ax,[YRes]
        inc        ax
        mul        [BytesPerLine]        ; DX:AX := number of bytes to fill
        mov        bx,ax                ; BX := bytes in last bank to fill
        mov        dh,dl                ; DH := number of full banks to fill

        mov        ax,VGABufferSeg
        mov        es,ax
        mov        di,[OriginOffset]    ; ES:DI -> video buffer
        mov        al,[BYTE BankOffset]; AL := starting bank number
        cld                            ; Moves go up in memory

        or        dh,dh                ; More than one bank to fill?
        jz        @@SingleBank        ; No, only fill a single bank

; Fill all of the full 64k banks first

@@OuterLoop:
        call    [NewBank]
        mov        cx,4000h            ; Need to set 4000h double words per bank
    rep    stosd
        inc        al
        dec        dh
        jnz        @@OuterLoop

; Now fill the last partial bank

@@SingleBank:
        call    [NewBank]
        mov        cx,bx
        shr        cx,2                ; CX := number of double words to set
    rep    stosd

; Restore graphics controller

        mov        dx,3CEh                ; DX := Graphics Controller I/O port
        xor        ax,ax                ; AH := 0, AL := 0
        out        dx,ax                ; Restore default Set/Reset register

        inc        ax                    ; AH := 0, AL := 1
        out        dx,ax                ; Restore enable Set/Reset register

        pop        di
        pop        si
        pop        bp
        ret

procend        _clear

;----------------------------------------------------------------------------
; void _copyTest(void)
;----------------------------------------------------------------------------
; Routine to copy the top half of video memory to the bottom half of
; video memory. To ensure that we a moving across a bank boundary in
; 16 color modes, we copy the data to the second video page.
;----------------------------------------------------------------------------
procstart    __copyTest

        push    si                    ; Save registers
        push    di
        push    ds

        mov        ax,[YRes]
        inc        ax
        shr        ax,1                ; AX := (Yres+1) / 2
        mul        [BytesPerLine]
        mov        cx,ax                ; CX := Number of bytes to move

; Set up graphics controller

        mov        dx,3CEh                ; DX := Graphics Controller address port
        mov        ax,0105h            ; AH := 1 (read mode 0, write mode 1)
                                    ; AL := 5 (Mode register number)
        out        dx,ax                ; Set up mode

        mov        di,[WORD PageSize]    ; ES:DI := offset into destination buffer
        mov        al,[BYTE PageSize+2]
        add        di,cx
        adc        al,0
        call    [NewBank]            ; Set the read/write bank number

        xor        si,si                ; DS:SI := offset into source buffer
        xor        al,al
        call    [ReadBank]            ; Set the read bank number

        mov        ax,VGABufferSeg
        mov        ds,ax                ; DS:SI -> source buffer
        mov        es,ax                ; ES:DI -> destination buffer
        cld                            ; Moves go up in memory

    rep    movsb                        ; Move all data in bank FAST!

; Restore default graphics controller state

        mov        ax,0005h            ; default mode register value
        out        dx,ax

        pop        ds
        pop        di
        pop        si
        ret

procend        __copyTest

;----------------------------------------------------------------------------
; void setActivePage(int which)
;----------------------------------------------------------------------------
; Routine to set the video page for active output.
;
; Entry:        page    - Page number of page to use
;
;----------------------------------------------------------------------------
procstart    _setActivePage

        ARG        which:WORD

        push    bp                    ; Set up stack frame
        mov        bp,sp

; Calculate 18 bit address of page in video memory

        xor        eax,eax
        mov        ax,[which]            ; EAX := page number
        mul        [PageSize]            ; EDX:EAX := result
        mov        [OriginOffset],ax    ; Save video buffer offset
        shr        eax,16
        mov        [BankOffset],ax        ; Save video bank offset

        pop        bp
        ret

procend        _setActivePage

;----------------------------------------------------------------------------
; void setVisualPage(int which)
;----------------------------------------------------------------------------
; Routine to set the visible video page.
;
; Entry:        page    - Page number of page to use
;
;----------------------------------------------------------------------------
procstart        _setVisualPage

        ARG        which:WORD

        push    bp                    ; Set up stack frame
        mov        bp,sp
        push    si

; Calculate 18 bit address of page in video memory

        xor        eax,eax
        mov        ax,[which]            ; EAX := page number
        mul        [PageSize]            ; EDX:EAX := result
        mov        bx,ax                ; BX := bottom 16 bits of address
        shr        eax,16
        push    ax                    ; Save top 2 bits of address

; Wait for display enable to be active (active low), to be sure that
; both halves of the start address will take place in one frame. We
; preload a few values here to save time after the DE has been
; detected.

        mov        cl,0Ch                ; CL := Start Address High register
        mov        ch,bh                ; CH := high byte of new address
        mov        bh,bl                ; BH := low byte of new address
        mov        bl,0Dh                ; BL := Start Address Low register
        mov        dx,03DAh            ; DX := video status port

@@WaitDE:
        in        al,dx
        test    al,1
        jnz        @@WaitDE            ; Wait for Display Enable

        cli
        pop        si                    ; SI := Bits 16+ for SuperVGA's
        call    [NewPage]            ; Program the start address
        sti

; Now wait for the start of the vertical sync, to ensure that the old
; page will be invisible before anything is drawn on it.

        mov        dx,03DAh            ; DX := video status port
@@WaitStartVert:
        in        al,dx                ; Wait for start of vertical retrace
        test    al,8
        jz        @@WaitStartVert

@@Exit:
        pop        si
        pop        bp
        ret

procend        _setVisualPage

;----------------------------------------------------------------------------
; void setBank(int bank)
;----------------------------------------------------------------------------
; Sets the current read and write bank to the specified 64k bank number.
;----------------------------------------------------------------------------
procstart    _setBank

        ARG        bank:WORD

        enter    0,0

        mov        al,[BYTE bank]
        cmp        al,[BYTE CurBank]
        je        @@NoChange

        call    [NewBank]

@@NoChange:
        leave
        ret

procend        _setBank

;----------------------------------------------------------------------------
; void setReadBank(int bank)
;----------------------------------------------------------------------------
; Sets the current read bank to the specified 64k bank. If you wish to set
; the read and write banks separately, call setBank() first, followed by
; setReadBank().
;----------------------------------------------------------------------------
procstart    _setReadBank

        ARG        bank:WORD

        enter    0,0

        mov        al,[BYTE bank]
        call    [ReadBank]

        leave
        ret

procend        _setReadBank

endcodeseg    svga16

        END