Date: Wed, 4 Aug 93 10:40:19 +0200
From: Mattolini Riccardo <mattolin AT aguirre DOT ing DOT unifi DOT it>
To: djgpp AT sun DOT soe DOT clarkson DOT edu
Subject: Realtek SVGA driver

Here is the source code for a new type driver for the Realtek SVGA (1M).
It has been coded modifying tr89000.asm. In fact the changes are only
to the tables of text and graphic modes and to the paging routine.
It supports modeX graphics too.
I tested it with modetest and with all the test programs that come with
libgrx 1.02 and it seems to have no problem.
If someone else using this SVGA board tries it and sends
me a bug report for any problem, I can try to fix it.
I will be very happy if Csaba includes this driver in the next release of
libgrx.

Bye R.Mattolini

Here the code:

--------------------------------Cut Here--------------------------------------
;--------------------------------------------------------------------------
; This is file realtek.ASM
;
; Copyright (C) 1991 DJ Delorie, 24 Kirsten Ave, Rochester NH 03867-2954
; Copyright (C) 1992 Csaba Biegl, 820 Stirrup Dr, Nashville, TN 37221
; Copyright (C) 1993 R Mattolini, 113 v. Guerrazzi, Sesto F.no Italy 50019
;
; This file is distributed under the terms listed in the document
; "copying.dj", available from DJ Delorie at the address above.
; A copy of "copying.dj" should accompany this file; if not, a copy
; should be available from where this file was obtained.  This file
; may not be distributed without a verbatim copy of "copying.dj".
;
; This file is distributed WITHOUT ANY WARRANTY; without even the implied
; warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
;--------------------------------------------------------------------------

include grdriver.inc
cseg	segment byte public 'code'
	assume  cs:cseg, ds:cseg, es:cseg, ss:nothing

req_T28         equ    1        ; enable  80x28x16 text mode
req_T50         equ    1        ; enable  80x50x16 text mode
req_3516        equ    1        ; enable  720x350x16 graphics mode
req_4816        equ    1        ; enable  720x480x16 graphics mode
req_lowX        equ    1        ; enable  320x240/320x400/360x480 256 color modes
req_hiX         equ    1        ; enable  high resolution mode X support

;--------------------------------------------------------------------------
; DRIVER HEADER
;  The following entries MUST match the structure and constant
;  declarations in the file 'grdriver.h' of the GRX graphics library
;  The mode word should contain the following bitfields:
;     - the GRD_NEW_DRIVER bit set for any new format driver
;     - the adapter type field should be specified
;     - the memory size field should be specified
;     - the paging mode field should be specified
;  The mode set routine will OR in the plane bitfield as it will
;  change when different color number modes are requested.
;--------------------------------------------------------------------------

	dw	offset mode_set_routine
	dw	offset paging_routine
mode_W  dw	GRD_NEW_DRIVER+GRD_VGA+GRD_1024K+GRD_RW_64K
;
; The 'def_xx' fields are filled in by go32 from the corresponding
; fields of the 'GO32' environment variable
;
def_tw  dw	80		; text width
def_th  dw	25		; text height
def_gw  dw	640		; graphics width
def_gh  dw	480		; graphics height
def_nc  dw	16		; graphics colors
	dw	offset driver_init_routine
	dw	offset text_mode_table
	dw	offset graphics_mode_table

;
; Biggest text and graphics sizes
;
Max_TW  equ	132
Max_TH  equ	60
Max_GWn equ	800		; non interlaced!!!
Max_GHn equ	600
Max_GW  equ	1024		; may be interlaced
Max_GH  equ	768


;--------------------------------------------------------------------------
; TABLE OF SUPPORTED TEXT MODES
;	- keep sorted by size
;	- end with an all 0 entry
;	- BIOS field = 0xff disables it
;	- fields:
;		width,  height, colors, BIOS#+  setup_procedure_index*256
;--------------------------------------------------------------------------
text_mode_table		label word
	dw	80,	25,	2,	007h +  00000h
	dw	40,	25,	16,	001h +  00000h
	dw	80,	25,	16,	003h +  00000h
    if req_T28
	dw      80,     28,     16,     003h +  val_T28
    endif
	dw	80,	30,	16,	018h +  00000h
	dw	80,	43,	16,	019h +  00000h
    if req_T50
	dw      80,     50,     16,     003h +  val_T50
    endif
	dw	80,	60,	16,	01ah +  00000h
	dw	132,	25,	16,	01bh +  00000h
	dw	132,	30,	16,	01ch +  00000h
	dw	132,	43,	16,	01dh +  00000h
	dw	132,	60,	16,	01eh +  00000h
	dw	0,	0,	0,	000h +  00000h


;--------------------------------------------------------------------------
; TABLE OF SUPPORTED GRAPHICS MODES
;	- keep sorted first by colors then by size
;	- end with an all 0 entry
;	- BIOS field = 0xff disables it
;	- fields:
;		width,  height, colors, BIOS#+  setup_procedure_index*256
;--------------------------------------------------------------------------
graphics_mode_table	label word
	dw	320,	200,	16,	00dh +  00000h
	dw	640,	200,	16,	00eh +  00000h
	dw	640,	350,	16,	010h +  00000h
	dw	640,	480,	16,	012h +  00000h
    if req_3516
	dw      720,    350,    16,     val_3516        ; Tweaked 16 color mode
    endif
    if req_4816
	dw      720,    480,    16,     val_4816        ; Tweaked 16 color mode
    endif
	dw	800,	600,	16,	01fh +  00000h
	dw	960,	720,	16,	020h +  00000h
	dw	1024,	768,	16,	021h +  00000h
	dw	1280,	1024,	16,	02ah +  00000h
	dw	320,	200,	256,	013h +  00000h
	dw      320,    200,    256,    013h +  val_hiX ; Mode X like
    if req_lowX
	dw      320,    240,    256,    val_lowXa       ; Mode X      (<64k)
	dw      320,    400,    256,    val_lowXb       ; Mode X      (<64k)
	dw      360,    480,    256,    val_lowXc       ; Mode X      (<64k)
    endif
	dw	640,	400,	256,	025h +  00000h
	dw	512,	512,	256,	024h +  00000h
	dw	640,	480,	256,	026h +  00000h
	dw	800,	600,	256,	027h +  00000h
	dw	1024,	768,	256,	028h +  00000h
	dw	1024,	1024,	256,	029h +  00000h
	dw	0,	0,	0,	000h +  00000h


;--------------------------------------------------------------------------
; TABLE OF SPECIAL SETUP PROCEDURES
;  You may need such procedures for:
;     -- reloading fonts on standard EGA or VGA for
;	 higher resolution text modes
;     -- enable HiColor mode of some Super VGAs
;     -- Handle the parameter passing conventions of the VESA BIOS
;     -- put VGA into 256 color plane mode ("MODE X")
;     -- etc...
;  There should be one entry in the table for every non-zero
;  'setup_procedure_index' in the text and graphics mode tables.
;  The first entry in the table belongs to index 100h, and so on.
;  The special setup procedure is invoked via a near call.
;
;  Entry: DI=address of the mode record from the text or graphics
;	  table to set up.
;
;  Exit:  Adapter configured
;	  BX=driver mode word as it should be returned by the mode set
;	     routine. Typically it involves picking up the mode word
;	     from the header and OR-ing in the appropriate bitplane mode
;	     bitfield. (This is not needed for text modes)
;	  AX, CX, DX, SI can be trashed, PRESERVE DI!!!!
;
;  NOTE: This runs in real mode, but don't mess with the segment registers.
;--------------------------------------------------------------------------
special_setup_table	label word
;       No chipset specific set up routines other than in vgaext.inc needed

include vgaext.inc      ; load VGA non BIOS modes


;--------------------------------------------------------------------------
; DRIVER INIT ROUTINE
;  called once after the driver is loaded
;  may do one or more of the followings:
;    - check for proper board type
;    - check amount of RAM on board, and:
;	-- update word in header to reflect correct amount
;	-- disable modes in the tables for which there is not enough RAM
;    - check for special equipment (HiColor DAC, etc...)
;
;  Entry: nothing
;
;  Exit:  AX=status:
;	   non-zero: OK,
;	   0: something went wrong (e.g. wrong adapter, etc..)
;	  BX,CX,DX may be trashed
;
;  NOTE: This runs in real mode, but don't mess with the segment registers.
;--------------------------------------------------------------------------
driver_init_routine	proc	far
	mov	ax,1
	ret
driver_init_routine	endp


;--------------------------------------------------------------------------
; MODE SET ROUTINE
;  sets up a text or graphics mode as close as possible to the one
;  reguested by the user with regard to number of colors and size.
;
;  Entry: AX=mode selection
;     0 = 80x25 text
;     1 = default text
;     2 = text CX cols by DX rows
;     3 = biggest text
;     4 = 320x200 graphics
;     5 = default graphics
;     6 = graphics CX width by DX height
;     7 = biggest non-interlaced graphics
;     8 = biggest graphics
;     9 = graphics BX colors, CX width by DX height
;
;  Exit: BX=driver mode flag
;	 CX=width (in pixels or characters)
;	 DX=height
;
;  NOTE: This runs in real mode, but don't mess with the segment registers.
;	 YOU SHOULD NOT NEED TO CHANGE THIS ROUTINE AS IT IS PRETTY
;	 MUCH TABLE DRIVEN
;--------------------------------------------------------------------------
mode_set_routine	proc	far
	push	ds
	push	di
	push	si
	mov	si,cs
	mov	ds,si
	cmp	ax,9
	jbe	DoIt
	jmp	Exit
DoIt:	add	ax,ax
	mov	si,ax
	jmp	WORD PTR mode_set_table[si]
mode_set_table  label	word
	dw	offset mode_0
	dw	offset mode_1
	dw	offset mode_2
	dw	offset mode_3
	dw	offset mode_4
	dw	offset mode_5
	dw	offset mode_6
	dw	offset mode_7
	dw	offset mode_8
	dw	offset mode_9
mode_0: mov	si,offset text_mode_table	; 80x25 text
	mov	bx,def_nc
	mov	cx,80
	mov	dx,25
	jmp	Lookup
mode_1: mov	si,offset text_mode_table	; default text
	mov	bx,def_nc
	mov	cx,def_tw
	mov	dx,def_th
	jmp	Lookup
mode_2: mov	si,offset text_mode_table	; CX*DX text
	mov	bx,def_nc
	jmp	Lookup
mode_3: mov	si,offset text_mode_table	; biggest text
	mov	bx,def_nc
	mov	cx,Max_TW
	mov	dx,Max_TH
	jmp	Lookup
mode_4: mov	si,offset graphics_mode_table	; 320x200 graphics
	mov	bx,def_nc
	mov	cx,320
	mov	dx,200
	jmp	Lookup
mode_5: mov	si,offset graphics_mode_table	; default graphics
	mov	bx,def_nc
	mov	cx,def_gw
	mov	dx,def_gh
	jmp	Lookup
mode_6: mov	si,offset graphics_mode_table	; CX*DX graphics
	mov	bx,def_nc
	jmp	Lookup
mode_7: mov	si,offset graphics_mode_table	; biggest non-interlaced gr
	mov	bx,def_nc
	mov	cx,Max_GWn
	mov	dx,Max_GHn
	jmp	Lookup
mode_8: mov	si,offset graphics_mode_table	; biggest graphics
	mov	bx,def_nc
	mov	cx,Max_GW
	mov	dx,Max_GH
	jmp	Lookup
mode_9: mov	si,offset graphics_mode_table	; CX*DX graphics w/ BX colors
;
; At this point:
;   SI points to the table to search (text or graphics)
;   BX has colors
;   CX has width
;   DX has height
;
Lookup: xor	ax,ax				; last color number seen
Find_C: cmp	[si+4],ax			; last color number == this?
	je	Same_C
	jb	Prev_C				; end of table -- use last color
	cmp	BYTE PTR [si+6],0ffh		; valid entry ?
	je	Prev_C				; not -- use last color
	mov	ax,[si+4]			; record color number
	mov	di,si				; start of entries w/ this color
	cmp	ax,bx				; enough colors ?
	jae	Find_S
Same_C: add	si,8
	jmp	Find_C
Prev_C: or	ax,ax				; found any color at all?
	je	Exit
;
; At this point:
;   DI points into the table to the first entry with the desired color
;      number (either it has enough colors or it is the highest color
;      number supported by the driver). Additionally, at least the
;      first (= smallest size) entry for this color is valid (has a
;      valid BIOS number).
;   AX has the color number adjusted for the driver
;   CX has width
;   DX has height
;
Find_S: cmp	[di+4],ax			; still the same color #?
	jne	Prev_S
	cmp	BYTE PTR [di+6],0ffh		; valid entry ?
	je	Prev_S
	cmp	[di],cx
	jb	Next_S
	cmp	[di+2],dx
	jae	GotIt
Next_S: add	di,8
	jmp	Find_S
Prev_S: sub	di,8
;
; At this point:
;   DI points to the table entry we want to set up
;
GotIt:  mov	ax,[di+6]			; BIOS mode number
	or	ah,ah				; special ?
	je	doBIOS
	mov	al,ah
	xor	ah,ah
	dec	ax
	add	ax,ax
	mov	si,ax
	call	WORD PTR special_setup_table[si]
	jmp	RetVal
doBIOS: int	10h
	mov	bx,GRD_1_PLANE
	cmp	WORD PTR [di+4],2		; 2 colors ?
	je	doFLAG
	mov	bx,GRD_4_PLANES
	cmp	WORD PTR [di+4],16		; 16 colors ?
	je	doFLAG
	mov	bx,GRD_8_PLANES
	cmp	WORD PTR [di+4],256		; 256 colors ?
	je	doFLAG
	mov	bx,GRD_16_PLANES
	cmp	WORD PTR [di+4],32768		; 32K colors ?
	je	doFLAG
	mov	bx,GRD_PLANE_MASK		; something is wrong!!
doFLAG: or	bx,mode_W
RetVal: mov	cx,[di]
	mov	dx,[di+2]
Exit:	pop	si
	pop	di
	pop	ds
	ret
mode_set_routine	endp


;--------------------------------------------------------------------------
; PAGING ROUTINE
;
;  Entry: AH=read page
;	  AL=write page
;
;  Exit: VGA configured.
;	 AX,BX,CX,DX,SI,DI may be trashed
;
;  NOTE: This runs in protected mode!  Don't mess with the segment registers!
;	 This code must be relocatable and may not reference any data!
;--------------------------------------------------------------------------
	assume  ds:nothing, es:nothing

paging_routine  proc	far
	mov cx,ax
	mov dx,3d6h
	mov al,ch
	out dx,al
	inc dx
	mov al,cl
	out dx,al
	ret
paging_routine  endp

cseg	ends
	end

-----------------------------------End---------------------------------------