tests/tcg/i386/test-i386-fscale.c

   1 /* Test fscale instruction.  */
   2
   3 #include <stdint.h>
   4 #include <stdio.h>
   5
   6 union u {
   7     struct { uint64_t sig; uint16_t sign_exp; } s;
   8     long double ld;
   9 };
  10
  11 volatile long double ld_third = 1.0L / 3.0L;
  12 volatile long double ld_four_thirds = 4.0L / 3.0L;
  13 volatile union u ld_invalid_1 = { .s = { 1, 1234 } };
  14 volatile union u ld_invalid_2 = { .s = { 0, 1234 } };
  15 volatile union u ld_invalid_3 = { .s = { 0, 0x7fff } };
  16 volatile union u ld_invalid_4 = { .s = { (UINT64_C(1) << 63) - 1, 0x7fff } };
  17
  18 volatile long double ld_res;
  19
  20 int isnan_ld(long double x)
  21 {
  22   union u tmp = { .ld = x };
  23   return ((tmp.s.sign_exp & 0x7fff) == 0x7fff &&
  24           (tmp.s.sig >> 63) != 0 &&
  25           (tmp.s.sig << 1) != 0);
  26 }
  27
  28 int issignaling_ld(long double x)
  29 {
  30     union u tmp = { .ld = x };
  31     return isnan_ld(x) && (tmp.s.sig & UINT64_C(0x4000000000000000)) == 0;
  32 }
  33
  34 int main(void)
  35 {
  36     short cw;
  37     int ret = 0;
  38     __asm__ volatile ("fscale" : "=t" (ld_res) :
  39                       "0" (2.5L), "u" (__builtin_nansl("")));
  40     if (!isnan_ld(ld_res) || issignaling_ld(ld_res)) {
  41         printf("FAIL: fscale snan\n");
  42         ret = 1;
  43     }
  44     __asm__ volatile ("fscale" : "=t" (ld_res) :
  45                       "0" (2.5L), "u" (ld_invalid_1.ld));
  46     if (!isnan_ld(ld_res) || issignaling_ld(ld_res)) {
  47         printf("FAIL: fscale invalid 1\n");
  48         ret = 1;
  49     }
  50     __asm__ volatile ("fscale" : "=t" (ld_res) :
  51                       "0" (2.5L), "u" (ld_invalid_2.ld));
  52     if (!isnan_ld(ld_res) || issignaling_ld(ld_res)) {
  53         printf("FAIL: fscale invalid 2\n");
  54         ret = 1;
  55     }
  56     __asm__ volatile ("fscale" : "=t" (ld_res) :
  57                       "0" (2.5L), "u" (ld_invalid_3.ld));
  58     if (!isnan_ld(ld_res) || issignaling_ld(ld_res)) {
  59         printf("FAIL: fscale invalid 3\n");
  60         ret = 1;
  61     }
  62     __asm__ volatile ("fscale" : "=t" (ld_res) :
  63                       "0" (2.5L), "u" (ld_invalid_4.ld));
  64     if (!isnan_ld(ld_res) || issignaling_ld(ld_res)) {
  65         printf("FAIL: fscale invalid 4\n");
  66         ret = 1;
  67     }
  68     __asm__ volatile ("fscale" : "=t" (ld_res) :
  69                       "0" (0.0L), "u" (__builtin_infl()));
  70     if (!isnan_ld(ld_res) || issignaling_ld(ld_res)) {
  71         printf("FAIL: fscale 0 up inf\n");
  72         ret = 1;
  73     }
  74     __asm__ volatile ("fscale" : "=t" (ld_res) :
  75                       "0" (__builtin_infl()), "u" (-__builtin_infl()));
  76     if (!isnan_ld(ld_res) || issignaling_ld(ld_res)) {
  77         printf("FAIL: fscale inf down inf\n");
  78         ret = 1;
  79     }
  80     /* Set round-downward.  */
  81     __asm__ volatile ("fnstcw %0" : "=m" (cw));
  82     cw = (cw & ~0xc00) | 0x400;
  83     __asm__ volatile ("fldcw %0" : : "m" (cw));
  84     __asm__ volatile ("fscale" : "=t" (ld_res) :
  85                       "0" (1.0L), "u" (__builtin_infl()));
  86     if (ld_res != __builtin_infl()) {
  87         printf("FAIL: fscale finite up inf\n");
  88         ret = 1;
  89     }
  90     __asm__ volatile ("fscale" : "=t" (ld_res) :
  91                       "0" (-1.0L), "u" (-__builtin_infl()));
  92     if (ld_res != -0.0L || __builtin_copysignl(1.0L, ld_res) != -1.0L) {
  93         printf("FAIL: fscale finite down inf\n");
  94         ret = 1;
  95     }
  96     /* Set round-to-nearest with single-precision rounding.  */
  97     cw = cw & ~0xf00;
  98     __asm__ volatile ("fldcw %0" : : "m" (cw));
  99     __asm__ volatile ("fscale" : "=t" (ld_res) :
 100                       "0" (ld_third), "u" (2.0L));
 101     cw = cw | 0x300;
 102     __asm__ volatile ("fldcw %0" : : "m" (cw));
 103     if (ld_res != ld_four_thirds) {
 104         printf("FAIL: fscale single-precision\n");
 105         ret = 1;
 106     }
 107     return ret;
 108 }