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Graphics 16,000
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graphics-16000.iso
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msdos
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animutil
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pvquan
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vga
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vga_retr.c
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C/C++ Source or Header
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1992-11-30
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1KB
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36 lines
/************************************************************************
* *
* Copyright (c) 1991, Frank van der Hulst *
* All Rights Reserved *
* *
* Authors: *
* FvdH - Frank van der Hulst (Wellington, NZ) *
* *
* Versions: *
* V1.1 910626 FvdH - QUANT released for DBW_RENDER *
* V1.2 911021 FvdH - QUANT released for PoV Ray *
* V1.3 911030 FvdH - Added 320x200x256x4 pages support *
* *
************************************************************************/
/*
VGA Vertical retrace detection module.
*/
#include <dos.h>
#include "vga.h"
#define DISPIO 0x3DA
#define VRT_bit 8
void WaitForVerticalRetrace(void)
{
static char chopper = 1;
while (inportb(DISPIO) & VRT_bit) /* wait */ ;
while ((inportb(DISPIO) & VRT_bit) == 0) /* wait */ ;
if ((chopper++ & 1)== 0) outportb(0x3fc, 1);
else outportb(0x3fc, 3);
}