VEX/test/fsave.c

   1
   2 #include <stdio.h>
   3 #include <stdlib.h>
   4
   5 void do_fsave ( void* p )
   6 {
   7    asm __volatile__("fninit");
   8    asm __volatile__("fldpi");
   9    asm __volatile__("fld1");
  10    asm __volatile__("fldln2");
  11    asm __volatile__("fsave (%0)" : : "r" (p) : "memory" );
  12 }
  13
  14 int isFPLsbs ( int i )
  15 {
  16    int q;
  17    q = 0; if (i == q || i == q+1) return 1;
  18    q = 10; if (i == q || i == q+1) return 1;
  19    q = 20; if (i == q || i == q+1) return 1;
  20    q = 30; if (i == q || i == q+1) return 1;
  21    q = 40; if (i == q || i == q+1) return 1;
  22    q = 50; if (i == q || i == q+1) return 1;
  23    q = 60; if (i == q || i == q+1) return 1;
  24    q = 70; if (i == q || i == q+1) return 1;
  25    return 0;
  26 }
  27
  28 void show_fpustate ( unsigned char* buf, int hide64to80 )
  29 {
  30    int i;
  31    printf("  0   ");
  32    for (i = 0; i < 14; i++)
  33       printf("%02x ", buf[i]);
  34    printf("\n");
  35
  36    printf(" 14   ");
  37    for (i = 14; i < 28; i++)
  38       printf("%02x ", buf[i]);
  39    printf("\n");
  40
  41    for (i = 0; i < 80; i++) {
  42       if ((i % 10) == 0)
  43          printf("%3d   ", i+28);
  44       if (hide64to80 && isFPLsbs(i))
  45          printf("xx ");
  46       else
  47          printf("%02x ", buf[i+28]);
  48       if (i > 0 && ((i % 10) == 9))
  49           printf("\n");
  50    }
  51 }
  52
  53 int main ( int argc, char** argv )
  54 {
  55    int i;
  56    unsigned char* buf = malloc(108);
  57    int xx = argc > 1;
  58    printf("Re-run with any arg to suppress least-significant\n"
  59           "   16 bits of FP numbers\n");
  60    for (i = 0; i < 108; i++)
  61       buf[i] = 0xAA;
  62
  63    /* dump FPU state in buf, and show it. */
  64    do_fsave(buf);
  65    show_fpustate( buf, xx );
  66
  67    return 0;
  68 }