World of Graphics/WOGRAPH.BIN/434.SV_BANKS.ASM

Assembly Source File | 1993-03-07 | 39KB | 1,436 lines

;****************************************************************************
;*
;*                        MegaGraph Graphics Library
;*
;*                  Copyright (C) 1993 Kendall Bennett.
;*                            All rights reserved.
;*
;* Filename:    $RCSfile: sv_banks.asm $
;* Version:        $Revision: 1.2 $
;*
;* Language:    80386 Assembler
;* Environment:    IBM PC (MS DOS)
;*
;* Description:    This source file contains the code needed to change banks
;*                on supported SuperVGA adapters, along with tables to find
;*                the correct routines for a specified video card.
;*
;*                The code in here originally appeared in John Bridges
;*                VGAKIT library, and has been modified to work with the
;*                MGL. Specifically support for individually setting the
;*                read and write banks has been included, along with adapter
;*                initialisation code (such as accessing extended registers
;*                etc).
;*
;*                To set up separate read/write banks, you must first call
;*                NewBank to set the read/write banks to the same value,
;*                then call ReadBank to change the read bank value.
;*
;* $Id: sv_banks.asm 1.2 1993/03/07 04:05:36 kjb Exp $
;*
;* Revision History:
;* -----------------
;*
;* $Log: sv_banks.asm $
;* Revision 1.2  1993/03/07  04:05:36  kjb
;* Bug fixes.
;*
;* Revision 1.1  1993/03/03  10:26:52  kjb
;* Initial revision
;*
;****************************************************************************

; Table of SuperVGA bank switching routines by video card.

SVGAInfoTable:
    dw    false,    VESA_bank,        VESA_bank,        VESA_init,        NONE_exit
    dw    true,    ATI_bank,        ATI_rbank,        ATI_init,        NONE_exit
    dw    false,    AHEADA_bank,    AHEADA_bank,    AHEAD_init,        AHEAD_exit
    dw    true,    AHEADB_bank,    AHEADB_rbank,    AHEAD_init,        AHEAD_exit
    dw    false,    CHIPS451_bank,    CHIPS451_bank,    CHIPS_init,        CHIPS_exit
    dw    false,    EVEREX_bank,    EVEREX_bank,    EVEREX_init,    NONE_exit
    dw    true,    GENOA_bank,        GENOA_rbank,    NONE_init,        NONE_exit
    dw    true,    OAK_bank,        OAK_rbank,        NONE_init,        NONE_exit
    dw    true,    PARADISE_bank,    PARADISE_rbank,    PARADISE_init,    PARADISE_exit
    dw    false,    TRIDENT_bank,    TRIDENT_bank,    TRIDENT_init,    NONE_exit
    dw    false,    TRIDENT_bank,    TRIDENT_bank,    TRIDENT_init,    NONE_exit
    dw    true,    VIDEO7V5_bank,    VIDEO7V5_rbank,    VIDEO7_init,    VIDEO7_exit
    dw    true,    ET3000_bank,    ET3000_rbank,    NONE_init,        NONE_exit
    dw    true,    ET4000_bank,    ET4000_rbank,    ET4000_init,    NONE_exit
    dw    true,    NCR_bank,        NCR_rbank,        NCR_init,        NONE_exit
    dw    false,    S3_bank,        S3_bank,        S3_init,        NONE_exit
    dw    false,    ACUMOS_bank,    ACUMOS_bank,    ACUMOS_init,    ACUMOS_exit
    dw    false,    AL2101_bank,    AL2101_bank,    AL2101_init,    NONE_exit
    dw    true,    MXIC_bank,        MXIC_rbank,        MXIC_init,        MXIC_exit
    dw    true,    P2000_bank,        P2000_rbank,    NONE_init,        NONE_exit
    dw    true,    RT3106_bank,    RT3106_rbank,    RT3106_init,    NONE_exit
    dw    false,    CIRRUS_bank,    CIRRUS_bank,    CIRRUS_init,    CIRRUS_exit

SVGAInfo:
TwoBanks    dw    0                ; Flags if two banks available
NewBank        dw    NONE_bank        ; Address of read/write bank switch routine
ReadBank    dw    NONE_bank        ; Address of read bank routine
InitSVGA    dw    NONE_init        ; Address of card Init routine
ExitSVGA    dw    NONE_exit        ; Address of card close routine
SVGAInfoSize    = ($-SVGAInfo)    ; Size of the above table

CurBank        dw    0FFh            ; Currently active read/write bank
VesaGran    db    0                ; VESA Granularity
VesaBank    dd    0                ; Address of VESA bank switch routine
VesaBuf        db    256 dup (?)        ; Place to store VESA Info

VesaModes:    dw    100h, grSVGA_640x400x256
            dw    101h, grSVGA_640x480x256
            dw    102h, grSVGA_800x600x16
            dw    103h, grSVGA_800x600x256
            dw    104h, grSVGA_1024x768x16
            dw    105h, grSVGA_1024x768x256
            dw    106h, grSVGA_1280x1024x16
            dw    107h, grSVGA_1280x1024x256
            dw    10Dh, grSVGA_320x200x32k
            dw    10Fh, grSVGA_320x200x16m
            dw    110h, grSVGA_640x480x32k
            dw    112h, grSVGA_640x480x16m
            dw    113h, grSVGA_800x600x32k
            dw    115h, grSVGA_800x600x16m
            dw    116h, grSVGA_1024x768x32k
            dw    118h, grSVGA_1024x768x16m
            dw    119h, grSVGA_1280x1024x32k
            dw    11Bh, grSVGA_1280x1024x16m
            dw    0

;----------------------------------------------------------------------------
; SetupBanks    Setup the SuperVGA bank switching routines
;----------------------------------------------------------------------------
;
; Given the id of the SuperVGA card that is installed, this routine sets
; up the following bank switching code.
;
; Registers:    AX,CX,SI,DI
;
;----------------------------------------------------------------------------
PROC    SetupBanks    near

        mov        [ReadBank],offset NONE_bank
        mov        [InitSVGA],offset NONE_init
        mov        ax,[CntDriver]
        cmp        ax,grSVGA
        jl        @@Exit                ; Not a SuperVGA adapter

        mov        si,offset SVGAInfoTable
        mov        ax,[CntDriver]        ; AX := number of current driver
        sub        ax,grSVGA            ; Adjust to start at 0 for SVGA's
        mov        cx,SVGAInfoSize
        mul        cx
        add        si,ax                ; SI := index into table of SVGA banks
        mov        di,offset SVGAInfo
        push    cs
        pop        es
    rep    movs    [BYTE es:di],[BYTE es:si]

@@Exit:
        mov        [CurBank],0FFh        ; Set the bank to nothing to start with
        ret

ENDP    SetupBanks

;----------------------------------------------------------------------------
; NewBank    Change to a new 64k bank on a SuperVGA card (reading and writing)
;----------------------------------------------------------------------------
;
; Changes to a new 64k bank given the specified index. The global variable
; CurBank is updated to reflect the current bank number and can be used
; to avoid unnecessary bank switching.
;
; These routines should set both the read and write bank for cards that
; support multiple banks to the same bank number.
;
; Note that the value of all regs MUST be preserved across this call.
;
; Entry:        AX    - Number of 64k bank (0-15 for 1Mb cards)
;
; Registers:    None.
;
;----------------------------------------------------------------------------

NONE_bank:
        ret

VESA_bank:
        mov        [CurBank],ax        ; Save the new bank number for later
        push    ax
        push    bx
        push    dx
        mul        [VesaGran]            ; Adjust with granularity factor
        push    ax
        mov        dx,ax                ; Select window position
        xor        bx,bx                ; BH := 0 (Select SVGA memory window)
                                    ; BL := 0 (window to set)
        call    [VesaBank]            ; Change bank A
        pop        dx                    ; Select window position
        inc        bx                    ; BL := 1 (window to set)
        call    [VesaBank]            ; Change bank B
        pop        dx
        pop        bx
        pop        ax
        ret

ATI_bank:
        mov        [CurBank],ax        ; Save the new bank number for later
        cli
        push    ax
        push    dx
        and        al,0Fh                ; Mask out bottom four bits
        mov        ah,al
        shl        ah,4                ; Shift read bank into position
        or        ah,al                ; AH := combined read/write register numbers
        rol        ah,1                ; Shift banks numbers in position
        mov        dx,1CEh                ; Port of extended registers
        mov        al,0B2h
        out        dx,ax                ; Set the ATI Bank Register
        pop        dx
        pop        ax
        sti
        ret

AHEADA_bank:
        mov        [CurBank],ax        ; Save the new bank number for later
        cli
        push    ax
        push    dx
        push    cx
        mov        ch,al
        mov        dx,03CCh            ; bit 0 in bit 5 of Misc Output reg
        in        al,dx                ; Read Misc output register
        mov        dl,0C2h
        and        al,11011111b
        shr        ch,1                ; Need to set the bit?
        jnc        @@SkpA                ; No, so skip it
        or        al,00100000b
@@SkpA:    out        dx,al                ; Set the new value
        mov        dx,3CEh                ; bits 3-1 in bits 2-0 of Segment Reg
        mov        al,0Dh                ; Index 0Dh for segment reg
        mov        ah,ch                ; ch contains top three bits shr 1
        out        dx,ax                ; Set the new value
        pop        cx
        pop        dx
        pop        ax
        sti
        ret

AHEADB_bank:
        mov        [CurBank],ax        ; Save the new bank number for later
        cli
        push    ax
        push    dx
        mov        ah,al                ; Combine read/write bank numbers
        shl        ah,4
        or        ah,al
        mov        al,0Dh                ; Index of Bank Switch register
        mov        dx,3CEh
        out        dx,ax                ; Set the register
        pop        dx
        pop        ax
        sti
        ret

CHIPS451_bank:
        mov        [CurBank],ax        ; Save the new bank number for later
        cli
        push    ax
        push    dx
        mov        ah,al
        mov        al,0Bh                ; Index of Single/Low Map register
        mov        dx,3D6h
        out        dx,ax                ; Set the register value
        pop        dx
        pop        ax
        sti
        ret

CHIPS452_bank:
        mov        [CurBank],ax        ; Save the new bank number for later
        cli
        push    ax
        push    dx
        mov        ah,al
        shl        ah,2                ; Change 64k bank into 16k bank number
        mov        al,10h                ; Index of Single/Low Map register
        mov        dx,3D6h
        out        dx,ax                ; Set the register value
        pop        dx
        pop        ax
        sti
        ret

CHIPS453_bank:
        mov        [CurBank],ax        ; Save the new bank number for later
        cli
        push    ax
        push    dx
        mov        ah,al
        shl        ah,4                ; Change 64k bank into 4k bank number
        mov        al,10h                ; Index of Single/Low Map register
        mov        dx,3D6h
        out        dx,ax                ; Set the register value
        pop        dx
        pop        ax
        sti
        ret

EVEREX_bank:
        mov        [CurBank],ax        ; Save the new bank number for later
        cli
        push    ax
        push    dx
        push    cx
        mov        cl,al
        mov        dx,3C4h
        mov        al,8
        out        dx,al
        inc        dl
        in        al,dx
        dec        dl
        shl        al,1
        shr        cl,1
        rcr        al,1
        mov        ah,al
        mov        al,8
        out        dx,ax                ; Bit 0 stored in 3C4 index 8 bit 7
        mov        dl,0CCh
        in        al,dx
        mov        dl,0C2h
        and        al,0DFh
        shr        cl,1
        jc        @@Nob2
        or        al,20h
@@Nob2:    out        dx,al                ; Bit 1 stored in 3C2 bit 5
        pop        cx
        pop        dx
        pop        ax
        sti
        ret

GENOA_bank:
        mov        [CurBank],ax        ; Save the new bank number for later
        cli
        push    ax
        push    dx
        mov        ah,al                ; Put read bank in bits 2-0 ...
        shl        al,3                ; ...  write bank in bits 5-3
        or        ah,al
        or        ah,40h                ; Set MEM bit
        mov        al,6                ; Index of Memory Segment Register
        mov        dx,3C4h
        out        dx,ax                ; Set the read/write banks
        pop        dx
        pop        ax
        sti
        ret

OAK_bank:
        mov        [CurBank],ax        ; Save the new bank number for later
        cli
        push    ax
        push    dx
        and        al,15
        mov        ah,al                ; Combine read/write bank numbers
        shl        al,4
        or        ah,al
        mov        al,11h                ; Index of bank switch register
        mov        dx,3DEh
        out        dx,ax                ; Set the register value
        pop        dx
        pop        ax
        sti
        ret

PARADISEPVGA_bank:
        mov        [CurBank],ax        ; Save the new bank number for later
        cli
        push    ax
        push    dx
        mov        dx,3CEh
        shl        al,4                ; change 64k bank into 4k bank number
        mov        ah,al
        mov        al,9                ; Index of PROA register
        out        dx,ax                ; Program PROA register
        pop        dx
        pop        ax
        sti
        ret

PARADISE_bank:
        mov        [CurBank],ax        ; Save the new bank number for later
        cli
        push    ax
        push    dx
        mov        dx,3CEh
        shl        al,4                ; change 64k bank into 4k bank number
        mov        ah,al
        mov        al,9                ; Index of PROA register (read bank)
        out        dx,ax                ; Program PROA register
        mov        al,0Ah                ; Index of PROB register (write bank)
        out        dx,ax                ; Program PROB register
        pop        dx
        pop        ax
        sti
        ret

TRIDENT_bank:
        mov        [CurBank],ax        ; Save the new bank number for later
        cli
        push    ax
        push    dx
        xor        al,2                ; Adjust page bit
        mov        ah,al
        mov        dx,3C4h
        mov        al,0Bh                ; Index of Chip Version register
        out        dx,al                ; Program index
        inc        dl
        xor        al,al
        out        dx,al                ; Force old definitions
        in        al,dx                ; Force new definitions
        dec        dl
        mov        al,0Eh                ; Index of New Mode Control Reg
        out        dx,ax                ; Program the page value
        pop        dx
        pop        ax
        sti
        ret

NCR_bank:
        mov        [CurBank],ax        ; Save the new bank number for later
        cli
        push    ax
        push    dx
        shl        al,2                ; Change 64k bank into 16k bank number
        cmp        [CntColors],gr16Color
        jne        @@NCR1
        shl        al,2                ; Change 64k bank into 4k bank number
@@NCR1:    mov        ah,al
        mov        al,18h
        mov        dx,3C4h
        out        dx,ax                ; Set write bank number
        mov        al,1Ch
        out        dx,ax                ; Set read bank number
        pop        dx
        pop        ax
        sti
        ret

VIDEO7_bank:
        mov        [CurBank],ax        ; Save the new bank number for later
        cli
        push    ax
        push    cx
        push    dx
        and        al,0Fh                ; Mask to 4 bits
        mov        ch,al
        mov        dx,3C4h
        mov        ah,ch
        and        ah,1
        mov        al,0F9h                ; Index of Extended Page Select register
        out        dx,ax                ; Program PS bit in register
        mov        al,ch
        and        al,1100b            ; Bits 3-2 for read field
        mov        ah,al
        shr        ah,2                ; Bits 1-0 for write field
        or        ah,al                ; Combine two values
        mov        al,0F6h
        out        dx,al                ; Index the bank select register
        inc        dl
        in        al,dx                ; Read old value
        and        al,11110000b        ; Zero out old bits
        or        al,ah                ; Combine with new values
        out        dx,al                ; Program the values
        mov        ah,ch
        and        ah,10b                ; Mask out bit 2
        shl        ah,4                ; Put into bit 5
        mov        dx,3CCh                ; Address Miscellaneous register
        in        al,dx                ; Read old value
        and        al,0DFh                ; Zero bit 5
        mov        dx,3C2h
        or        al,ah                ; Or in the page bit
        out        dx,al                ; Program the new value
        pop        dx
        pop        cx
        pop        ax
        sti
        ret

VIDEO7V5_bank:
        mov        [CurBank],ax        ; Save the new bank number for later
        cli
        push    ax
        push    dx
        and        al,0Fh                ; Mask to 4 bits
        shl        al,4                ; Shift into bits 7-4
        mov        ah,al
        mov        dx,3C4h
        mov        al,0E8h                ; Index of write bank register
        out        dx,ax                ; Program the write bank
        mov        al,0E9h                ; Index of read bank register
        out        dx,ax                ; Program the read bank
        pop        dx
        pop        ax
        sti
        ret

ET3000_bank:
        mov        [CurBank],ax        ; Save the new bank number for later
        cli
        push    ax
        push    dx
        and        al,7                ; Mask out bottom 3 bits
        mov        ah,al                ; Combine read and write bank values in al
        shl        ah,3
        or        al,ah
        or        al,40h                ; Set bit 6 to select 64k segments
        mov        dx,3CDh                ; Point to memory segment register
        out        dx,al                ; Set the new bank value
        pop        dx
        pop        ax
        sti
        ret

ET4000_bank:
        mov        [CurBank],ax        ; Save the new bank number for later
        cli
        push    ax
        push    dx
        and        al,0Fh                ; Mask out bottom 4 bits
        mov        ah,al                ; Combine read and write values in al
        shl        ah,4
        or        al,ah
        mov        dx,3CDh                ; Point to memory segment register
        out        dx,al                ; Set the new bank value
        pop        dx
        pop        ax
        sti
        ret

S3_bank:
        mov        [CurBank],ax        ; Save the new bank number for later
        cli
        push    ax
        push    cx
        push    dx
        mov        dx,3D4h
        cmp        [CntColors],gr16Color
        jne        @@S31
        shl        al,2                ; bank = bank * 4 in 16 color modes
@@S31:    and        al,0Fh                ; Mask off all but bottom 4 bits
        mov        cl,al
        mov        ax,4838h            ; Enable extended registers
        out        dx,ax
        mov        al,31h                ; Index of S3R1
        out        dx,al
        inc        dl
        in        al,dx                ; Read value of S3R1
        or        al,9                ; Set bits 0 and 3
        or         al,1001b
        out        dx,al                ; Write value back again
        dec        dl
        mov        al,35h                ; Index of S3R5
        out        dx,al
        inc        dl
        in        al,dx                ; Read value of S3R5
        and        al,0F0h                ; Mask off low nybble
        or        al,cl                ; Or in new bank number
        out        dx,al                ; Write the value back again
        dec        dl
        mov        ax,0038h            ; Disable extended registers
        out        dx,ax
        pop        dx
        pop        cx
        pop        ax
        sti
        ret

CIRRUS_bank:
        mov        [CurBank],ax        ; Save the new bank number for later
        cli
        push    ax
        push    dx
        mov        dx,3CEh
        shl        al,4                ; Convert to 4k bank number
        mov        ah,al
        mov        al,9
        out        dx,ax
        pop        dx
        pop        ax
        sti
        ret

ACUMOS_bank:
        mov        [CurBank],ax        ; Save the new bank number for later
        cli
        push    ax
        push    dx
        mov        dx,3CEh
        shl        al,4                ; Convert to 4k bank number
        mov        ah,al
        mov        al,9
        out        dx,ax
        pop        dx
        pop        ax
        sti
        ret

AL2101_bank:
        mov        [CurBank],ax        ; Save the new bank number for later
        cli
        push    ax
        push    dx
        mov        dx,3D6h
        out        dx,al                ; Set read bank register
        inc        dx
        out        dx,al                ; Set write bank
        pop        dx
        pop        ax
        sti
        ret

MXIC_bank:
        mov        [CurBank],ax        ; Save the new bank number for later
        cli
        push    ax
        push    dx
        and        al,0Fh                ; Mask out all but 4 bottom bits
        mov        ah,al                ; Combine read/write bank numbers
        shl        al,4
        or        ah,al
        mov        al,0C5h                ; Index of bank switch register
        mov        dx,3C4h
        out        dx,ax                ; Set the register value
        pop        dx
        pop        ax
        sti
        ret

P2000_bank:
        mov        [CurBank],ax        ; Save the new bank number for later
        cli
        push    ax
        push    dx
        mov        dx,3D6h
        out        dx,al                ; Set write bank register
        inc        dx
        out        dx,al                ; Set read bank
        pop        dx
        pop        ax
        sti
        ret

RT3106_bank:
        mov        [CurBank],ax        ; Save the new bank number for later
        cli
        push    ax
        push    dx
        mov        dx,3D6h
        out        dx,al                ; Set write bank register
        inc        dx
        out        dx,al                ; Set read bank
        pop        dx
        pop        ax
        sti
        ret

;----------------------------------------------------------------------------
; ReadBank    Change to a new 64k read bank on a SuperVGA card
;----------------------------------------------------------------------------
;
; Changes to a new 64k bank for reading given the specified index. The write
; bank should be preserved across this call.We also trash the value in
; CurBank to indicate that bank switching needs to be done again to set
; the read and write banks to the same value.
;
; Note that the value of all regs MUST be preserved across this call.
;
; Entry:        AX    - Number of 64k bank (0-15 for 1Mb cards)
;
; Registers:    None.
;
;----------------------------------------------------------------------------

VESA_rbank:
        mov        [CurBank],0FFh        ; Trash CurBank with invalid value
        push    ax
        push    bx
        push    dx
        mul        [VesaGran]            ; Adjust with granularity factor
        mov        dx,ax                ; Select window position
        xor        bh,bh                ; BH := 0 (Select SVGA memory window)
        mov        bl,1                ; Window to set
        call    [VesaBank]            ; Change bank
        pop        dx
        pop        bx
        pop        ax
        ret

ATI_rbank:
        mov        [CurBank],0FFh        ; Trash CurBank with invalid value
        cli
        push    ax
        push    dx
        and        al,0Fh                ; Mask out bottom four bits
        rol        al,5                ; Shift read bank into position
        mov        ah,al
        mov        dx,1CEh                ; Port of extended registers
        mov        al,0B2h
        out        dx,al                ; Index ATI bank register
        inc        dl
        in        al,dx
        and        al,01Eh                ; Zero out bits 7-5 and bit 0
        or        ah,al                ; AL := combined value
        mov        al,0B2h
        out        dx,ax                ; Ouput the new value
        pop        dx
        pop        ax
        sti
        ret

AHEADB_rbank:
        mov        [CurBank],ax        ; Save the new bank number for later
        cli
        push    ax
        push    dx
        mov        ah,al                ; Read bank number in bits 3-0
        mov        al,0Dh                ; Index of Bank Switch register
        mov        dx,3CEh
        out        dx,al
        inc        dl
        in        al,dx                ; Read old register value
        and        al,0F0h                ; Mask out bits 3-0
        or        al,ah                ; Combine with new value
        out        dx,al                ; Set the new register value
        pop        dx
        pop        ax
        sti
        ret

GENOA_rbank:
        mov        [CurBank],0FFh        ; Trash CurBank with invalid value
        cli
        push    ax
        push    dx
        and        al,7                ; Mask out bottom three bits
        mov        ah,al
        mov        dx,3C4h
        mov        al,6                ; Index of Memory Segment Register
        out        dx,al                ; Output index
        inc        dl
        in        al,dx                ; Read current value
        and        al,0F8h                ; Zero bits 2-0
        or        al,ah                ; Or in new value
        out        dx,al                ; Output the new bank
        pop        dx
        pop        ax
        sti
        ret

OAK_rbank:
        mov        [CurBank],0FFh        ; Trash CurBank with invalid value
        cli
        push    ax
        push    dx
        and        al,15
        mov        ah,al                ; AH := read bank number
        mov        al,11h                ; Index of bank switch register
        mov        dx,3DEh
        out        dx,al
        inc        dl
        in        al,dx                ; Read old value
        and        al,0F0h                ; Mask out read bank value
        or        al,ah                ; Or in new value
        out        dx,al                ; Program the new value
        pop        dx
        pop        ax
        sti
        ret

PARADISE_rbank:
        mov        [CurBank],0FFh        ; Trash CurBank with invalid value
        cli
        push    ax
        push    dx
        mov        dx,3CEh
        shl        al,4                ; change 64k bank into 4k bank number
        mov        ah,al
        mov        al,09h                ; Index of PROA register (read bank)
        out        dx,ax                ; Program PROA register
        pop        dx
        pop        ax
        sti
        ret

NCR_rbank:
        mov        [CurBank],0FFh        ; Trash CurBank with invalid value
        cli
        push    ax
        push    dx
        shl        al,2                ; Change 64k bank into 16k bank number
        cmp        [CntColors],gr16Color
        jne        @@NCR2
        shl        al,2                ; Change 64k bank into 4k bank number
@@NCR2:    mov        ah,al
        mov        al,1Ch
        mov        dx,3C4h
        out        dx,ax                ; Set read bank number
        pop        dx
        pop        ax
        sti
        ret

VIDEO7V5_rbank:
        mov        [CurBank],0FFh        ; Trash CurBank with invalid value
        cli
        push    ax
        push    dx
        and        al,0Fh                ; Mask to 4 bits
        shl        al,4                ; Shift into bits 7-4
        mov        ah,al
        mov        dx,3C4h
        mov        al,0E9h                ; Index of read bank register
        out        dx,al                ; Program the value
        pop        dx
        pop        ax
        sti
        ret

ET3000_rbank:
        mov        [CurBank],0FFh        ; Trash CurBank with invalid value
        cli
        push    ax
        push    dx
        mov        ah,bl                ; Save value of bl
        and        al,7                ; Mask out bottom 3 bits
        shl        al,3                ; Shift into position
        mov        bl,al
        mov        dx,3CDh
        in        al,dx                ; Read current value
        and        al,0C7h                ; Mask out read bank select value
        or        al,bl                ; Or in the new read bank value
        out        dx,al                ; Set the new bank value
        mov        bl,ah                ; Restore value of bl
        pop        dx
        pop        ax
        sti
        ret

ET4000_rbank:
        mov        [CurBank],0FFh        ; Trash CurBank with invalid value
        cli
        push    ax
        push    dx
        mov        ah,bl                ; Save value of bl
        and        al,0Fh                ; Mask out bottom 4 bits
        shl        al,4                ; Shift into position
        mov        bl,al
        mov        dx,3CDh
        in        al,dx                ; Read current value
        and        al,00Fh                ; Mask out read bank select bits 7-4
        or        al,bl                ; Or in the new read bank value
        out        dx,al                ; Set the new bank value
        mov        bl,ah                ; Restore value of bl
        pop        dx
        pop        ax
        sti
        ret

AL2101_rbank:
        mov        [CurBank],0FFh        ; Trash CurBank with invalid value
        cli
        push    ax
        push    dx
        mov        dx,3D6h
        out        dx,al                ; Set read bank register
        pop        ax
        pop        dx
        sti
        ret

MXIC_rbank:
        mov        [CurBank],0FFh        ; Trash CurBank with invalid value
        cli
        push    ax
        push    dx
        and        al,0Fh                ; Mask out all but 4 bottom bits
        shl        al,4
        mov        ah,al
        mov        al,0C5h                ; Index of bank switch register
        mov        dx,3C4h
        out        dx,al
        inc        dx
        in        al,dx                ; Read old value
        and        al,0Fh                ; Mask out old read bank values
        or        al,ah
        out        dx,al                ; Set the register value
        pop        dx
        pop        ax
        sti
        ret

P2000_rbank:
        mov        [CurBank],0FFh        ; Trash CurBank with invalid value
        cli
        push    ax
        push    dx
        mov        dx,3D7h
        out        dx,al                ; Set read bank
        pop        dx
        pop        ax
        sti
        ret

RT3106_rbank:
        mov        [CurBank],0FFh        ; Trash CurBank with invalid value
        cli
        push    ax
        push    dx
        mov        dx,3D6h
        out        dx,al                ; Set read bank register
        pop        ax
        pop        dx
        sti
        ret

;----------------------------------------------------------------------------
; InitBank    Initialise the SuperVGA card for bank switching if required
;----------------------------------------------------------------------------
;
; Peforms any initialisations required by the SuperVGA card prior to bank
; switching (accessing extended registers, setting the mode etc).
;
; Note:    All register may be used without concern for saving their values
;
; Registers:    All.
;
;----------------------------------------------------------------------------

PROC    NONE_init    near
        ret
ENDP    NONE_init

;----------------------------------------------------------------------------
; VESA_init
;----------------------------------------------------------------------------
; We have a VESA SuperVGA adapter, so determine the granularity and address
; of the VESA bank switching routine. We simply determine whether we are
; in 16 or 256 color video modes, and get information about these modes.
;----------------------------------------------------------------------------
PROC    VESA_init    near

        push    cs
        pop        es
        mov        di,offset VesaBuf    ; ES:DI -> Buffer for VESA info
        mov        bx,[CntMode]
        mov        si,offset VesaModes    ; CS:SI -> Table of VESA video modes

        mov        cx,102h                ; 800 x 600 16 color
        cmp        bx,grVGA_640x480x16
        jle        @@NonVESA
        mov        cx,101h                ; 640 x 480 256 color
        cmp        bx,grVGA_320x200x256
        je        @@NonVESA

@@ModeLoop:
        lods    [WORD cs:si]
        mov        cx,ax                ; CX := VESA Mode Number
        jcxz    @@Exit                ; Fall through if no match
        lods    [WORD cs:si]
        cmp        ax,bx
        jne        @@ModeLoop

        mov        ax,4F01h
        int        10h                    ; Call the video BIOS to get info

        mov        ax,[CntMode]
        mov        bx,[WORD VesaBuf+16]
        call    setBytesPerLine
        mov        [BytesPerLine],bx
        jmp        @@SaveValues

@@NonVESA:
        mov        ax,4F01h
        int        10h

@@SaveValues:
        mov        ax,[WORD VesaBuf+12]; Save pointer to bank switching routine
        mov        [WORD VesaBank],ax
        mov        ax,[WORD VesaBuf+14]
        mov        [WORD VesaBank+2],ax

        mov        cx,[WORD VesaBuf+4]    ; Load VESA granularity value
        mov        al,1
        cmp        cx,0                ; Some BIOS'S fuck this up!
        je        @@NoDivide
        mov        ax,64
        div        cl
@@NoDivide:
        mov     [VesaGran],al        ; Save the granularity scale factor

; Now determine if this video card supports multiple banks

        mov        ax,[WORD VesaBuf+2]    ; Get Window attributes
        and        ah,0111b            ; Mask out appropriate bits
        cmp        ah,0011b            ; Check if second window is only readable
        jne        @@Exit                ; No, so we are done

        mov        [TwoBanks],true
        mov        [ReadBank],offset VESA_rbank

@@Exit:
        ret

ENDP    VESA_init

;----------------------------------------------------------------------------
; ATI_init
;----------------------------------------------------------------------------
; We have an ATI video card. The 18800-1 and 28800 chips support the dual
; paging mode, but the old 18800 chip does not.
;----------------------------------------------------------------------------
PROC    ATI_init near

        push    bp

        cmp        [CntChipID],grATI_18800
        jne        @@Not18800

; We have an 18800 based ATI SuperVGA, so modify to not use separate read
; write banks.

        mov        [TwoBanks],false
        mov        [ReadBank],offset ATI_bank
        jmp        @@Exit

; We have an 18800-1 or 28800 Chip, so setup for dual bank mode

@@Not18800:
        modinx    1CEh, 0BEh, 01000b, 01000b    ; Set bit 3 ATI Register E

@@Exit:
        pop        bp
        ret

ENDP    ATI_init

;----------------------------------------------------------------------------
; AHEAD_init
;----------------------------------------------------------------------------
; We have an Ahead A or B SuperVGA. We simply enable the extended registers
; to save time during bank switching.
;----------------------------------------------------------------------------
PROC    AHEAD_init    near

        outp    3CEh, 0Fh, 20h        ; Enable extended registers
        modinx    3CEh, 0Ch, 20h, 20h    ; Enable enhanced mode
        ret

ENDP    AHEAD_init

;----------------------------------------------------------------------------
; CHIPS_init
;----------------------------------------------------------------------------
; We have a Chips & Technologies 82c451/452/453. To save time during
; bank switching, we enable the SuperVGA extended registers here.
; We also determine the type of chipset installed and setup bank switching
; and page flipping according to the chip type.
;----------------------------------------------------------------------------
PROC    CHIPS_init    near

        outp    46E8h, 1Eh            ; Place chip in setup mode
        outp    103h, 80h            ; Enable extended registers
        outp    46E8h, 0Eh            ; Bring chip out of setup mode
        modinx    3D6h, 4, 4, 4        ; Enable bank access and extended CRTC
        modinx    3D6h, 0Dh, 3, 1        ; Enable extended paging

; Set the bank switching code according to the C&T chipset type

        mov        bx,[CntChipID]        ; BX := chip id

        cmp        bx,grCHIPS_82c451
        je        @@Chips451            ; Done for 82c451
        cmp        bx,grCHIPS_82c452
        je        @@Chips452

        mov        [NewBank],offset CHIPS453_bank
        mov        [ReadBank],offset CHIPS453_bank
        jmp        @@Exit

@@Chips452:
        mov        [NewBank],offset CHIPS452_bank
        mov        [ReadBank],offset CHIPS452_bank
        jmp        @@Exit

; Extended page flipping is not available on 82c451 chips, so disable it

@@Chips451:
        mov        [WORD cs:CHIPSPageOfs],offset NONE_page

@@Exit:
        ret

ENDP    CHIPS_init

;----------------------------------------------------------------------------
; EVEREX_init
;----------------------------------------------------------------------------
; Some Everex video boards are based on Trident or ET4000 chips. Detect
; them here, and setup to use the correct bank switching and page flipping
; routines.
;----------------------------------------------------------------------------
PROC    EVEREX_init        near

        mov        ax,[CntChipID]        ; AX := chipset ID
        cmp        ax,grEVEREX_Ev236    ; UltraGraphics - Trident Chip
        je        @@TridentChip
        cmp        ax,grEVEREX_Ev620    ; Vision VGA - Trident Chip
        je        @@TridentChip
        cmp        ax,grEVEREX_Ev629    ; ViewPoint TC - ET4000 Chip
        je        @@ET4000Chip
        cmp        ax,grEVEREX_Ev673    ; EVGA - Trident Chip
        je        @@TridentChip
        cmp        ax,grEVEREX_Ev678    ; Viewpoint - Trident Chip
        jne        @@Exit                ; Normal Everex chip, all done

; Based on Trident chip, so determine the type (8800 or 8900).

@@TridentChip:
        mov        [TwoBanks],false
        mov        [NewBank],offset TRIDENT_bank
        mov        [ReadBank],offset TRIDENT_bank
        mov        [WORD cs:EVEREXPageOfs],offset TRIDENT88_page

        wrinx    3C4h, 0Bh, 0        ; Force old definitions
        inp        3C5h                ; Force new definitions
        and        al,0Fh
        cmp        al,2
        je        @@Exit                ; Done for Trident 8800
        mov        [WORD cs:EVEREXPageOfs],offset TRIDENT89_page
        jmp        @@Exit

@@ET4000Chip:
        mov        [TwoBanks],true
        mov        [NewBank],offset ET4000_bank
        mov        [ReadBank],offset ET4000_rbank
        mov        [WORD cs:EVEREXPageOfs],offset ET4000_page
        jmp        @@Exit

@@Exit:
        ret

ENDP    EVEREX_init

;----------------------------------------------------------------------------
; PARADISE_init
;----------------------------------------------------------------------------
; We have a Paradise PVGA1A or WD90Cxx SuperVGA. We simply enable access
; to the extended registers to save time during bank switching.
;----------------------------------------------------------------------------
PROC    PARADISE_init    near

; Enable paradise extensions

        wrinx    3CEh, 0Fh, 5        ; Turn off write protect on VGA registers
        wrinx    3C4h, 6h, 48h        ; Unlock extended sequencer regs
        wrinx    3D4h, 29h, 85h        ; Turn on access to PR10-17

; Turn off the standard VGA mem bit, to allow access to all of the SuperVGA
; video memory for extended page flipping.

        modinx    3D4h, 2Fh, 2, 0        ; Clear out the VGA MEM bit

; Now determine the Paradise Chipset type. The WD90C10 and above chipsets
; support the dual banking mode.

        cmp        [CntChipID],grPARA_90C10
        jge        @@HaveDualMode

; Have an old PVGA1 or WD90C00 video card without dual banking support

        mov        [TwoBanks],false
        mov        [NewBank],offset PARADISEPVGA_bank
        mov        [ReadBank],offset PARADISEPVGA_bank
        jmp        @@Exit

; We have a WD90C1x/3x chipset, so set up for dual banking
; operation (read/write operation).

@@HaveDualMode:
        modinx    3CEh, 0Bh, 8, 8        ; Enable both PROA and PROB
        modinx    3C4h, 11h, 80h, 80h    ; Set PROA for read, PROB for write

@@Exit:
        ret

ENDP    PARADISE_init

;----------------------------------------------------------------------------
; TRIDENT_init
;----------------------------------------------------------------------------
; We have a Trident 8800 or 8900 SuperVGA. Setup for a pagesize of 64k
; before doing bank switching.
;----------------------------------------------------------------------------
PROC    TRIDENT_init

        modinx    3CEh, 6, 4, 4        ;  Set pagesize to 64k
        ret

ENDP    TRIDENT_init

;----------------------------------------------------------------------------
; VIDEO7_init
;----------------------------------------------------------------------------
; We have a Video7 V7VGA SuperVGA. Enable access to the extended registers
; to save time during bank switching.
;----------------------------------------------------------------------------
PROC    VIDEO7_init

        outp    3C4h, 6, 0EAh        ; Enable extended registers

; Determine if the chip is revision five or later, so we can support
; dual read/write bank operation.

        rdinx    3C4h, 08Eh            ; Read Chip Revision register
        cmp        al,05Ah                ; Is this a version 5 chip?
        jl        @@HaveV5            ; We have a version 5 or later chip

; If the card is a 1024i, I am not sure if it has a version 4 or version 5
; chip in it. I assume here that it has a version 5 chip. If it does not,
; (or does not seem to work), uncomment the following code and replace
; the above line:
;
;        jg        @@NotV5                ; version 1-3 V7VGA's
;        cmp        al,050h
;        jge        @@HaveV5            ; Yes, version 5 chip

@@NotV5:
        mov        [TwoBanks],false
        mov        [NewBank],offset VIDEO7_bank
        mov        [ReadBank],offset VIDEO7_bank
        jmp        @@Exit

; We have a V7VGA revision 5 or later chip, so setup for dual paging
; mode

@@HaveV5:
        modinx    3C4h, 0E0h, 80h, 80h    ; Set split bank mode

@@Exit:
        ret

ENDP    VIDEO7_init

;----------------------------------------------------------------------------
; ET4000_init
;----------------------------------------------------------------------------
; We have an ET4000 video card, so enable access to extended registers
; before bank switching.
;----------------------------------------------------------------------------
PROC    ET4000_init

        outp    3BFh, 3
        outp    3D8h, 0A0h            ; Enable ET4000 extensions

; Check the type of video board, modifying the 24 bit mode tables if
; we have a Speedstar 24 or Genoa 7900 board.

        cmp        [CntChipID],grET4000_MEGAEVA
        je        @@Done

; We have a Speedstar 24 or Genoa 7900, both which only support the
; 640x480 video modes. Note that on both these cards, the bytes per line
; value for the mode is 2048, not 1920 (so you don't have problems with
; pixels crossing bank boundaries!!).

        mov        [DWORD cs:ET4_640x350x16m],0
        mov        [DWORD cs:ET4_640x400x16m],0
        mov        bx,2048
        mov        ax,grSVGA_640x480x16m
        call    setBytesPerLine

        cmp        [CntChipID],grET4000_SPEEDSTAR
        jne        @@HaveGenoa

        mov        [DWORD cs:ET4_640x480x16m],02E10E0h
        jmp        @@Done

@@HaveGenoa:
        mov        [DWORD cs:ET4_640x480x16m],03E10F0h

@@Done:
        ret

ENDP

;----------------------------------------------------------------------------
; NCR_init
;----------------------------------------------------------------------------
; We have an NCR 77C22E SuperVGA, so set up for dual banking mode of
; operation. We also program the low portions of the bank switching
; registers with zeroes.
;----------------------------------------------------------------------------
PROC    NCR_init

        modinx    3C4h, 1Eh, 010100b, 010100b
        wrinx    3C4h, 19h, 0    ; Set primary offset low to 0
        wrinx    3C4h, 1Dh, 0    ; Set secondary offset low to 0
        ret

ENDP

;----------------------------------------------------------------------------
; S3_init
;----------------------------------------------------------------------------
; We have an S3 based video card, so set up a few things specific to this
; card.
;----------------------------------------------------------------------------
PROC    S3_init

; The S3 Chipset uses large bytes per line values in 256, 32k and 64k
; color video modes to make the copper's life a little easier (and ours
; a little harder :-). Change the bytes per line values in the table
; to the correct values.

        call    ModifyS3BytesPerLine
        ret

ENDP    S3_init

;----------------------------------------------------------------------------
; CIRRUS_init
;----------------------------------------------------------------------------
; We have a Cirrus 5422 SuperVGA, so enable access to extended registers.
;----------------------------------------------------------------------------
PROC    CIRRUS_init

        wrinx    3C4h, 6, 12h        ; Enable extended registers
        ret

ENDP    CIRRUS_init

;----------------------------------------------------------------------------
; ACUMOS_init
;----------------------------------------------------------------------------
; We have an AcuMos SuperVGA, so enable access to extended registers.
;----------------------------------------------------------------------------
PROC    ACUMOS_init

        wrinx    3C4h, 6, 12h        ; Enable extended registers
        ret

ENDP    ACUMOS_init

;----------------------------------------------------------------------------
; AL2101_init
;----------------------------------------------------------------------------
; We have an Advance Logic 2101 SuperVGA, so set up for separate read
; write bank switching. This is supposed to work according to the
; docs on the AL2101, but it doesn't (it works for the RealTek instead!)
; Very wierd!!
;----------------------------------------------------------------------------
PROC    AL2101_init

;        modinx    3CEh, 0Fh, 4, 4    ; Set bit 2 of Extended function register
        ret

ENDP    AL2101_init

;----------------------------------------------------------------------------
; MXIC_init
;----------------------------------------------------------------------------
; We have an MXIC SuperVGA, so enable access to extended registers.
;----------------------------------------------------------------------------
PROC    MXIC_init

        wrinx    3C4h, 0A7h, 087h    ; Enable extended registers
        ret

ENDP    MXIC_init

;----------------------------------------------------------------------------
; RT3106_init
;----------------------------------------------------------------------------
; We have a RealTek 3106 SuperVGA. This code is supposed to work on the
; advance logic's ALG2101 chip, but apparantly works on the RT3106!
;----------------------------------------------------------------------------
PROC    RT3106_init

        modinx    3CEh, 0Fh, 4, 4    ; Set bit 2 of Extended function register
        ret

ENDP    RT3106_init

;----------------------------------------------------------------------------
; ExitBank    Deinitialises the SuperVGA card back to normal operation.
;----------------------------------------------------------------------------
;
; Returns the SuperVGA card back to it's default state, such as turning
; off access to all extended registers that were set by the initialisation
; routines.
;
; Note:    All register may be used without concern for saving their values
;
; Registers:    All.
;
;----------------------------------------------------------------------------

PROC    NONE_exit    near
        ret
ENDP    NONE_exit

PROC    AHEAD_exit    near

        outp    3CEh, 0Fh, 0        ; Disable extended registers
        ret

ENDP    AHEAD_exit

PROC    CHIPS_exit    near

        outp    46E8h, 1Eh            ; Place chip in setup mode
        outp    103h, 0                ; Disable extended registers
        outp    46E8h, 0Eh            ; Bring chip out of setup mode
        ret

ENDP    CHIPS_exit

PROC    PARADISE_exit    near

        wrinx    3CEh, 0Fh, 0        ; Turn on write protect on VGA registers
        wrinx    3CEh, 6h, 0            ; Turn on write protect on extended seq
        ret

ENDP    PARADISE_exit

PROC    VIDEO7_exit

        outp    3C4h, 6, 0AEh        ; Disable extended registers
        ret

ENDP    VIDEO7_exit

PROC    CIRRUS_exit

        wrinx    3C4h, 6, 0            ; Disable extended registers
        ret

ENDP    CIRRUS_exit

PROC    ACUMOS_exit

        wrinx    3C4h, 6, 0            ; Disable extended registers
        ret

ENDP    ACUMOS_exit

PROC    MXIC_exit

        wrinx    3C4h, 0A7h, 0        ; Disable extended registers
        ret

ENDP    MXIC_exit