280 lines
9.5 KiB
HTML
280 lines
9.5 KiB
HTML
<HTML>
|
|
<HEAD>
|
|
<META name=vsisbn content="1576101746">
|
|
<META name=vstitle content="Michael Abrash's Graphics Programming Black Book, Special Edition">
|
|
<META name=vsauthor content="Michael Abrash">
|
|
<META name=vspublisher content="The Coriolis Group">
|
|
<META name=vspubdate content="07/01/97">
|
|
<META name=vscategory content="Web and Software Development: Game Development,Web and Software Development: Graphics and Multimedia Development">
|
|
|
|
|
|
|
|
|
|
|
|
|
|
<TITLE>Michael Abrash's Graphics Programming Black Book Special Edition: Be It Resolved: 360x480</TITLE>
|
|
|
|
<!-- HEADER -->
|
|
<!-- Empty Reference Subhead -->
|
|
|
|
<!--ISBN=1576101746//-->
|
|
<!--TITLE=Michael Abrash's Graphics Programming Black Book Special Edition//-->
|
|
<!--AUTHOR=Michael Abrash//-->
|
|
<!--PUBLISHER=The Coriolis Group, Inc.//-->
|
|
<!--CHAPTER=32//-->
|
|
<!--PAGES=611-615//-->
|
|
<!--UNASSIGNED1//-->
|
|
<!--UNASSIGNED2//--></HEAD><BODY LINK=#0000FF ALINK=#000099 VLINK=#0000FF BGCOLOR=#FFFFFF>
|
|
|
|
<CENTER>
|
|
<TABLE BORDER>
|
|
<TR>
|
|
<TD><A HREF="32-01.html">Previous</A></TD>
|
|
<TD><A HREF="index.html">Table of Contents</A></TD>
|
|
<TD><A HREF="32-03.html">Next</A></TD>
|
|
</TR>
|
|
</TABLE>
|
|
</CENTER>
|
|
<P><BR></P>
|
|
<P><B>LISTING 32.1 L32-1.ASM</B></P>
|
|
<!-- CODE //-->
|
|
<PRE>
|
|
; Borland C/C++ tiny/small/medium model-callable assembler
|
|
; subroutines to:
|
|
;* Set 360×480 256-color VGA mode
|
|
;* Draw a dot in 360×480 256-color VGA mode
|
|
;* Read the color of a dot in 360×480 256-color VGA mode
|
|
;
|
|
; Assembled with TASM
|
|
;
|
|
; The 360×480 256-color mode set code and parameters were provided
|
|
; by John Bridges, who has placed them into the public domain.
|
|
;
|
|
VGA_SEGMENT equ 0a000h ;display memory segment
|
|
SC_INDEX equ 3c4h ;Sequence Controller Index register
|
|
GC_INDEX equ 3ceh ;Graphics Controller Index register
|
|
MAP_MASK equ 2 ;Map Mask register index in SC
|
|
READ_MAP equ 4 ;Read Map register index in GC
|
|
SCREEN_WIDTH equ 360 ;# of pixels across screen
|
|
WORD_OUTS_OK equ 1 ;set to 0 to assemble for
|
|
; computers that can’t handle
|
|
; word outs to indexed VGA registers
|
|
;
|
|
_DATAsegmentpublic byte ‘DATA’
|
|
;
|
|
; 360×480 256-color mode CRT Controller register settings.
|
|
; (Courtesy of John Bridges.)
|
|
;
|
|
vptbl dw 06b00h ; horz total
|
|
dw 05901h ; horz displayed
|
|
dw 05a02h ; start horz blanking
|
|
dw 08e03h ; end horz blanking
|
|
dw 05e04h ; start h sync
|
|
dw 08a05h ; end h sync
|
|
dw 00d06h ; vertical total
|
|
dw 03e07h ; overflow
|
|
dw 04009h ; cell height
|
|
dw 0ea10h ; v sync start
|
|
dw 0ac11h ; v sync end and protect cr0-cr7
|
|
dw 0df12h ; vertical displayed
|
|
dw 02d13h ; offset
|
|
dw 00014h ; turn off dword mode
|
|
dw 0e715h ; v blank start
|
|
dw 00616h ; v blank end
|
|
dw 0e317h ; turn on byte mode
|
|
vpend label word
|
|
_DATAends
|
|
;
|
|
; Macro to output a word value to a port.
|
|
;
|
|
OUT_WORDmacro
|
|
if WORD_OUTS_OK
|
|
out dx,ax
|
|
else
|
|
out dx,al
|
|
inc dx
|
|
xchg ah,al
|
|
out dx,al
|
|
dec dx
|
|
xchg ah,al
|
|
endif
|
|
endm
|
|
;
|
|
_TEXTsegment byte public ‘CODE’
|
|
assumecs:_TEXT, ds:_DATA
|
|
;
|
|
; Sets up 360×480 256-color mode.
|
|
; (Courtesy of John Bridges.)
|
|
;
|
|
; Call as: void Set360By480Mode()
|
|
;
|
|
; Returns: nothing
|
|
;
|
|
public _Set360×480Mode
|
|
_Set360×480Modeprocnear
|
|
push si ;preserve C register vars
|
|
push di
|
|
mov ax,12h ; start with mode 12h
|
|
int 10h ; let the BIOS clear the video memory
|
|
|
|
mov ax,13h ; start with standard mode 13h
|
|
int 10h ; let the BIOS set the mode
|
|
|
|
mov dx,3c4h ; alter sequencer registers
|
|
mov ax,0604h ; disable chain 4
|
|
out dx,ax
|
|
|
|
mov ax,0100h ; synchronous reset
|
|
out dx,ax ; asserted
|
|
mov dx,3c2h ; misc output
|
|
mov al,0e7h ; use 28 mHz dot clock
|
|
out dx,al ; select it
|
|
mov dx,3c4h ; sequencer again
|
|
mov ax,0300h ; restart sequencer
|
|
out dx,ax ; running again
|
|
|
|
mov dx,3d4h ; alter crtc registers
|
|
|
|
mov al,11h ; cr11
|
|
out dx,al ; current value
|
|
inc dx ; point to data
|
|
in al,dx ; get cr11 value
|
|
and al,7fh ; remove cr0 -> cr7
|
|
out dx,al ; write protect
|
|
dec dx ; point to index
|
|
cld
|
|
mov si,offset vptbl
|
|
mov cx,((offset vpend)-(offset vptbl)) shr 1
|
|
@b: lodsw
|
|
out dx,ax
|
|
loop @b
|
|
pop di ;restore C register vars
|
|
pop si
|
|
ret
|
|
_Set360x480Modeendp
|
|
;
|
|
; Draws a pixel in the specified color at the specified
|
|
; location in 360×480 256-color mode.
|
|
;
|
|
; Call as: void Draw360×480Dot(int X, int Y, int Color)
|
|
;
|
|
; Returns: nothing
|
|
;
|
|
DParms struc
|
|
dw ? ;pushed BP
|
|
dw ? ;return address
|
|
DrawX dw ? ;X coordinate at which to draw
|
|
DrawY dw ? ;Y coordinate at which to draw
|
|
Color dw ? ;color in which to draw (in the
|
|
; range 0-255; upper byte ignored)
|
|
DParms ends
|
|
;
|
|
public _Draw360×480Dot
|
|
_Draw360×480Dotprocnear
|
|
push bp ;preserve caller’s BP
|
|
mov bp,sp ;point to stack frame
|
|
push si ;preserve C register vars
|
|
push di
|
|
mov ax,VGA_SEGMENT
|
|
mov es,ax ;point to display memory
|
|
mov ax,SCREEN_WIDTH/4
|
|
;there are 4 pixels at each address, so
|
|
; each 360-pixel row is 90 bytes wide
|
|
; in each plane
|
|
mul [bp+DrawY] ;point to start of desired row
|
|
mov di,[bp+DrawX] ;get the X coordinate
|
|
shr di,1 ;there are 4 pixels at each address
|
|
shr di,1 ; so divide the X coordinate by 4
|
|
add di,ax ;point to the pixel’s address
|
|
mov cl,byte ptr [bp+DrawX] ;get the X coordinate again
|
|
and cl,3 ;get the plane # of the pixel
|
|
mov ah,1
|
|
shl ah,cl ;set the bit corresponding to the plane
|
|
; the pixel is in
|
|
mov al,MAP_MASK
|
|
mov dx,SC_INDEX
|
|
OUT_WORD ;set to write to the proper plane for
|
|
; the pixel
|
|
mov al,byte ptr [bp+Color] ;get the color
|
|
stosb ;draw the pixel
|
|
pop di ;restore C register vars
|
|
pop si
|
|
pop bp ;restore caller’s BP
|
|
ret
|
|
_Draw360×480Dotendp
|
|
;
|
|
; Reads the color of the pixel at the specified
|
|
; location in 360×480 256-color mode.
|
|
;
|
|
; Call as: int Read360×480Dot(int X, int Y)
|
|
;
|
|
; Returns: pixel color
|
|
;
|
|
RParms struc
|
|
dw ? ;pushed BP
|
|
dw ? ;return address
|
|
ReadX dw ? ;X coordinate from which to read
|
|
ReadY dw ? ;Y coordinate from which to read
|
|
RParms ends
|
|
;
|
|
public _Read360×480Dot
|
|
_Read360×480Dotprocnear
|
|
push bp ;preserve caller’s BP
|
|
mov bp,sp ;point to stack frame
|
|
push si ;preserve C register vars
|
|
push di
|
|
mov ax,VGA_SEGMENT
|
|
mov es,ax ;point to display memory
|
|
mov ax,SCREEN_WIDTH/4 ;there are 4 pixels at each address, so
|
|
; each 360-pixel row is 90 bytes wide
|
|
; in each plane
|
|
|
|
mul [bp+DrawY] ;point to start of desired row
|
|
mov si,[bp+DrawX] ;get the X coordinate
|
|
shr si,1 ;there are 4 pixels at each address
|
|
shr si,1 ; so divide the X coordinate by 4
|
|
add si,ax ;point to the pixel’s address
|
|
mov ah,byte ptr [bp+DrawX] ;get the X coordinate again
|
|
and ah,3
|
|
;get the plane # of the pixel
|
|
mov al,READ_MAP
|
|
mov dx,GC_INDEX
|
|
OUT_WORD ;set to read from the proper plane for
|
|
; the pixel
|
|
lods byte ptr es:[si] ;read the pixel
|
|
sub ah,ah ;make the return value a word for C
|
|
pop di ;restore C register vars
|
|
pop si
|
|
pop bp ;restore caller’s BP
|
|
ret
|
|
_Read360×480Dot endp
|
|
_TEX Tends
|
|
end
|
|
</PRE>
|
|
<!-- END CODE //-->
|
|
<P><BR></P>
|
|
<CENTER>
|
|
<TABLE BORDER>
|
|
<TR>
|
|
<TD><A HREF="32-01.html">Previous</A></TD>
|
|
<TD><A HREF="index.html">Table of Contents</A></TD>
|
|
<TD><A HREF="32-03.html">Next</A></TD>
|
|
</TR>
|
|
</TABLE>
|
|
</CENTER>
|
|
|
|
<hr width="90%" size="1" noshade>
|
|
<div align="center">
|
|
<font face="Verdana,sans-serif" size="1">Graphics Programming Black Book © 2001 Michael Abrash</font>
|
|
</div>
|
|
<!-- all of the reference materials (books) have the footer and subfoot reveresed -->
|
|
<!-- reference_subfoot = footer -->
|
|
<!-- reference_footer = subfoot -->
|
|
|
|
<!-- BEGIN SUB FOOTER -->
|
|
</BODY>
|
|
</HTML>
|
|
|
|
<!-- END FOOTER -->
|
|
|
|
|