;**************************************************************************** ;* ;* The Universal VESA VBE ;* ;* Copyright (C) 1993 Kendall Bennett. ;* All rights reserved. ;* ;* Filename: $RCSfile: _s3.asm $ ;* Version: $Revision: 1.2 $ ;* ;* Language: 8086 Assembler ;* Environment: IBM PC (MS DOS) ;* ;* Description: Assembly language support routines for S3 SuperVGA's. ;* ;* Contains code to perform initialisation, bank switching ;* and extended page flipping if possible. ;* ;* Note that the code to perform bank switching and page ;* flipping must be _completely_ relocatable, so you cannot ;* access any global variables from within these routines. ;* For this reason if bank switching is performed differently ;* in 16 color planar modes, you must have a separate ;* routine for the 16 color modes. ;* ;* $Id: _s3.asm 1.2 1993/09/24 05:23:19 kjb release $ ;* ;* Revision History: ;* ----------------- ;* ;* $Log: _s3.asm $ ;* Revision 1.2 1993/09/24 05:23:19 kjb ;* Fixed a number of bugs. ;* ;* Revision 1.1 1993/09/19 01:26:54 kjb ;* Initial revision ;* ;**************************************************************************** grS3_911 = 0 ; S3 86c911 SuperVGA chip grS3_924 = 1 ; S3 86c924 SuperVGA chip grS3_801_805 = 2 ; S3 86c801/86c805 SuperVGA chip grS3_928 = 4 ; S3 86c928 SuperVGA chip ;---------------------------------------------------------------------------- ; S3_bank16 Change to a new 64k bank (reading and writing) - 16 color mode ;---------------------------------------------------------------------------- ; ; Changes to a new 64k bank for reading and writing on the S3 86c911 and ; S3 86c924 chipsets when running in 16 color planar mode. ; ; Entry: AX - Number of 64k bank ; ; Registers: All preserved! ; ;---------------------------------------------------------------------------- PROC S3_bank16 far push ax push cx push dx mov dx,3D4h shl al,2 ; bank = bank * 4 in 16 color modes mov ch,al ; Save value for later 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 S3MOD2: mov al,grS3_911 ; Default to 911 chipset (modified) cmp al,grS3_801_805 jb @@911 ; Chip is a 911 or 924 mov ax,0A039h ; Unlock system control registers out dx,ax mov al,51h ; Index of CR51 out dx,al inc dl in al,dx ; Read value of CR51 and al,0C0h ; Clear out old values and ch,30h ; Mask out appropriate bits shr ch,2 or al,ch ; Or in top 2 bits of bank number out dx,al ; Write the value back again dec dl mov ax,0039h ; Lock system control registers out dx,ax @@911: mov ax,0038h ; Disable extended registers out dx,ax pop dx pop cx pop ax ret ENDP S3_bank16_len = ($-S3_bank16) ; Length of relocatable routine ;---------------------------------------------------------------------------- ; S3_bank256 Change to a new 64k bank (reading and writing) ;---------------------------------------------------------------------------- ; ; Changes to a new 64k bank for reading and writing on the S3 86c911 and ; S3 86c924 chipsets in 256 color and above modes. ; ; Entry: AX - Number of 64k bank ; ; Registers: All preserved! ; ;---------------------------------------------------------------------------- PROC S3_bank256 far push ax push cx push dx mov dx,3D4h mov ch,al ; Save value for later and al,0Fh ; Mask off all but bottom 4 bits mov cl,al mov ax,4838h ; Enable extended registers out dx,ax mov al,31h ; Index of S3R1 out dx,al inc dl in al,dx ; Read value of S3R1 or al,9 ; Set bits 0 and 3 or al,1001b out dx,al ; Write value back again dec dl mov al,35h ; Index of S3R5 out dx,al inc dl in al,dx ; Read value of S3R5 and al,0F0h ; Mask off low nybble or al,cl ; Or in new bank number out dx,al ; Write the value back again dec dl S3MOD1: mov al,grS3_911 ; Default to 911 chipset (modified) cmp al,grS3_801_805 jb @@911 ; Chip is a 911 or 924 mov ax,0A039h ; Unlock system control registers out dx,ax mov al,51h ; Index of CR51 out dx,al inc dl in al,dx ; Read value of CR51 and al,0C0h ; Clear out old values and ch,30h ; Mask out appropriate bits shr ch,2 or al,ch ; Or in top 2 bits of bank number out dx,al ; Write the value back again dec dl mov ax,0039h ; Lock system control registers out dx,ax @@911: mov ax,0038h ; Disable extended registers out dx,ax pop dx pop cx pop ax ret ENDP S3_bank256_len = ($-S3_bank256) ; Size of relocatable routine ;---------------------------------------------------------------------------- ; S3_page Set the extended CRT starting address for S3 chipsets. ;---------------------------------------------------------------------------- ; ; Entry: BL - Index of start address low register ; BH - Bits 7-0 of new start address ; CL - Index of start address high register ; CH - Bits 15-8 of new start address ; SI - Bits 16+ for new start address ; ; Registers: AX,BX,CX,DX,SI ; ;---------------------------------------------------------------------------- PROC S3_page far SetLowStartAddress mov bh,bl ; Save top 4 bits mov dx,3D4h ; DX := CRTC I/O port mov ax,4838h ; Enable extended registers out dx,ax mov al,31h ; Index of S3R1 out dx,al inc dl in al,dx ; Read old value of S3R1 and al,0CFh ; Mask off bits 5-4 and bl,3 ; Mask off bottom two bits shl bl,4 ; Shift into bit pos 5-4 or al,bl ; Or in starting address value out dx,al ; Set the new value dec dl S3MOD3: mov al,grS3_911 ; Default to 911 chipset (modified) cmp al,grS3_801_805 jb @@911 ; Chip is a 911 or 924 mov ax,0A039h ; Unlock system control registers out dx,ax mov al,51h ; Index of CR51 out dx,al inc dl in al,dx ; Read value of CR51 and al,3 ; Clear out old values shr bh,2 and bh,3 ; Mask off bottom two bits or al,bh ; Or in top 2 bits of start address out dx,al ; Write the value back again dec dl mov ax,0039h ; Lock system control registers out dx,ax @@911: mov ax,0038h ; Disable extended registers out dx,ax ret ENDP S3_page_len = ($-S3_page) ; Length of relocatable routine ;---------------------------------------------------------------------------- ; S3_init ;---------------------------------------------------------------------------- ; We have an S3 based video card, so set up a few things specific to this ; card. ;---------------------------------------------------------------------------- PROC S3_init ; Setup the correct vectors to use the S3 bank switching and paging routines mov [TwoBanks],false mov [WriteBank16],offset S3_bank16 mov [WriteBank16Len],S3_bank16_len mov [WriteBank256],offset S3_bank256 mov [WriteBank256Len],S3_bank256_len mov [NewPage16],offset S3_page mov [NewPage16Len],S3_page_len mov [NewPage256],offset S3_page mov [NewPage256Len],S3_page_len ; Bank switching on the 801/805/928 chipsets is more complicated, as you ; can possibly access up to 4Mb of memory (on the 928) which needs to be ; addressed. We use modify the code in the bank switching routine depending ; on the type of chipset currently installed. mov al,[BYTE CntChipID] mov [BYTE S3MOD1+1],al ; Modify the bank16 code mov [BYTE S3MOD2+1],al ; Modify the bank256 code mov [BYTE S3MOD3+1],al ; Modify the page flipping code ret ENDP S3_init