From: csantill AT lausd DOT k12 DOT ca DOT us
Message-ID: <33CFAD70.1366@lausd.k12.ca.us>
Date: Fri, 18 Jul 1997 10:53:17 -0700
MIME-Version: 1.0
To: djgpp AT delorie DOT com
Subject: Uclock & Clock causing SIG error w/O3 and greater
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from: csantill AT lausd DOT k12 DOT ca DOT us

Now that I got some working mode 13h code to hack
(thanx alot to Sinan!), I decided to test how fast
it was.  I've been using uclock & clock to do my
timing procedures but I always seem to get a
SIGFPE error(division by zero) at line 54:

fps=7680/((t[2]-t[1])/UCLOCKS_PER_SEC)
                or
fps=7680/((t[2]-t[1])/CLOCKS_PER_SEC)

This is odd because it does not occur when I compile
w/O0 or O1.

Here's my code if anybody is interested.

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#include <sys/farptr.h>
#include <dpmi.h>
#include <go32.h>

#include <time.h>

#include <string.h>
#include <stdio.h>

enum GR_MODE{GR_INVALID=-1, GR_TEXT=0x03, GR_VGA=0x13};

enum GR_MODE Set_GR_Mode(enum GR_MODE mode)
{
  __dpmi_regs r;

  memset(&r, 0, sizeof(r));
  r.x.ax=mode;

  return(__dpmi_int(0x10,&r) ? GR_INVALID:mode);
}

void put_pix_far(int x, int y, int c)
{
  _farpokeb(_dos_ds, 0xA0000+y*320+x,c);
  return;
}

int main(void)
{
  int x, y, co;
  char c,c1;
  int fps;
//  uclock_t t[2];
  clock_t t[2];

  if(GR_INVALID==Set_GR_Mode(GR_VGA))
  {
    printf("Error setting mode 13h\n");
    exit(8);
  }

  clock();

 t[1]=clock();
//  t[1]=uclock();
  for(c=0; c<30; c++)
    for(co=0; co<256; co++)
      for(y=0; y<200; y++)
        for(x=0; x<320; x++)
          put_pix_far(x,y,co);
  t[2]=clock();
//  t[2]=uclock();

  Set_GR_Mode(GR_TEXT);

  fps=7680/((t[2]-t[1])/CLOCKS_PER_SEC);
//  fps=7680/((t[2]-t[1])/UCLOCKS_PER_SEC);

  printf("fps = %d\n",fps);

  getchar();

  return 0;

}

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