;--------------------------------------------------------------------------
; This is file ATIVGA.ASM
;
; Copyright (C) 1991 DJ Delorie, 24 Kirsten Ave, Rochester NH 03867-2954
; Copyright (C) 1992 Csaba Biegl, 820 Stirrup Dr, Nashville, TN 37221
;
; 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


;--------------------------------------------------------------------------
; 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_256K+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	80
Max_TH  equ	50
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
	dw	80,	28,	16,	003h +  00100h
	dw	80,	50,	16,	003h +  00200h
	dw	132,	25,	16,	023h +  00000h
	dw	132,	28,	16,	023h +  00100h
	dw	132,	44,	16,	033h +  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
	dw	800,	600,	16,	054h +  00000h
	dw	1024,	768,	16,	055h +  00000h
	dw	320,	200,	256,	013h +  00000h
	dw	640,	400,	256,	061h +  00000h
	dw	640,	480,	256,	062h +  00000h
;	dw	800,	600,	256,	063h +  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
	dw	offset  VGA_28row_mode_set
	dw	offset  VGA_50row_mode_set
	dw	offset  VGA_MODE_X_set

;
; Routine to set up VGA 50 row mode
; interface is described above
;
VGA_50row_mode_set	proc	near
	mov	ax,03h			; set 80x25 mode
	int	10h
	xor	bx,bx
	mov	ax,1112h		; load 8x8 font
	int	10h
	ret
VGA_50row_mode_set	endp

VGA_28row_mode_set	proc	near
	mov	ax,WORD PTR [di+6]	; set 25 line mode
	xor	ah,ah
	int	10h
	xor	bx,bx
	mov	ax,1111h		; load 8x14 font
	int	10h
	ret
VGA_28row_mode_set	endp

;
; Routine to set up VGA 256 color plane mode ("MODE X")
; interface is described above
; TO BE COMPLETED
;
VGA_MODE_X_set		proc	near
	mov	bx,mode_W
	or	bx,GRD_8_X_PLANES
	ret
VGA_MODE_X_set		endp


;--------------------------------------------------------------------------
; 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
	and	ah,07h		; Read-plane on bits 7-6-5
	ror	ah,1
	ror	ah,1
	ror	ah,1

	and	al,07h		; Write-plane on bits 3-2-1
	shl	al,1

	or	ah,al		; Combine Read and Write plane

	mov	dx,01ceh	; ATI register
	mov	al,0b2h		; plane select
	out	dx,ax
	ret
paging_routine  endp


cseg	ends
	end