test/frstor.c

#include <stdio.h>
#include <stdlib.h>

void do_fsave ( void* p )
{
   asm __volatile__("fsave (%0)" : : "r" (p) : "memory" );
}

void do_frstor ( void* p )
{
   asm __volatile__("frstor (%0)" : : "r" (p) : "memory" );
}


int isFPLsbs ( int i )
{
   int q;
   q = 0; if (i == q || i == q+1) return 1;
   q = 10; if (i == q || i == q+1) return 1;
   q = 20; if (i == q || i == q+1) return 1;
   q = 30; if (i == q || i == q+1) return 1;
   q = 40; if (i == q || i == q+1) return 1;
   q = 50; if (i == q || i == q+1) return 1;
   q = 60; if (i == q || i == q+1) return 1;
   q = 70; if (i == q || i == q+1) return 1;
   return 0;
}

void show_fpustate ( unsigned char* buf, int hide64to80 )
{
   int i;
   printf("  0   ");
   for (i = 0; i < 14; i++)
      printf("%02x ", buf[i]);
   printf("\n");

   printf(" 14   ");
   for (i = 14; i < 28; i++)
      printf("%02x ", buf[i]);
   printf("\n");

   for (i = 0; i < 80; i++) {
      if ((i % 10) == 0)
         printf("%3d   ", i+28);
      if (hide64to80 && isFPLsbs(i))
	 printf("xx ");
      else
         printf("%02x ", buf[i+28]);
      if (i > 0 && ((i % 10) == 9))
          printf("\n");
   }
}

int main ( int argc, char** argv )
{
   int i;
   unsigned short* buf = malloc(54*sizeof(short));
   int xx = argc > 1;
   printf("Re-run with any arg to suppress least-significant\n"
          "   16 bits of FP numbers\n");

   for (i = 0; i < 54; i++)
      buf[i] = i;
   buf[0] = 0x037f;

   for (i = 0; i < 8; i++)
      *(long double *)(&buf[14+5 *i]) = 20.0 + 0.1234 * i;

   do_frstor(buf);
   do_fsave(buf);

   show_fpustate( (unsigned char*)buf, xx );

   return 0;
}