xserver/hw/xfree86/os-support/misc/SlowBcopy.c

50 lines
1.0 KiB
C

/*
* Create a dependency that should be immune from the effect of register
* renaming as is commonly seen in superscalar processors. This should
* insert a minimum of 100-ns delays between reads/writes at clock rates
* up to 100 MHz---GGL
*/
#ifdef HAVE_XORG_CONFIG_H
#include <xorg-config.h>
#endif
#include <X11/X.h>
#include "xf86.h"
#include "xf86Priv.h"
#include "xf86_OSlib.h"
#include "compiler.h"
static int really_slow_bcopy;
void
xf86SetReallySlowBcopy(void)
{
really_slow_bcopy = 1;
}
#if defined(__i386__) || defined(__amd64__)
static void xf86_really_slow_bcopy(unsigned char *src, unsigned char *dst, int len)
{
while(len--)
{
*dst++ = *src++;
outb(0x80, 0x00);
}
}
#endif
/* The outb() isn't needed on my machine, but who knows ... -- ost */
void
xf86SlowBcopy(unsigned char *src, unsigned char *dst, int len)
{
#if defined(__i386__) || defined(__amd64__)
if (really_slow_bcopy) {
xf86_really_slow_bcopy(src, dst, len);
return;
}
#endif
while(len--)
*dst++ = *src++;
}