none/tests/mips32/change_fp_mode.c

   1 #if defined(__mips_hard_float)
   2
   3 #include <elf.h>
   4 #include <stdio.h>
   5 #include <stdlib.h>
   6 #include <sys/prctl.h>
   7
   8 #if !defined(PR_SET_FP_MODE)
   9 #   define PR_SET_FP_MODE 45
  10 #endif
  11
  12 #if !defined(PR_GET_FP_MODE)
  13 #   define PR_GET_FP_MODE 46
  14 #endif
  15
  16 /* Determine FP mode based on sdc1 behavior
  17    returns 1 if FR = 1 mode is detected. */
  18
  19 static int get_fp_mode(void) {
  20    unsigned long long result = 0;
  21    __asm__ volatile(
  22       ".set push\n\t"
  23       ".set noreorder\n\t"
  24       ".set oddspreg\n\t"
  25       "lui $t0, 0x3FF0\n\t"
  26       "ldc1 $f0, %0\n\t"
  27       "mtc1 $t0, $f1\n\t"
  28       "sdc1 $f0, %0\n\t"
  29       ".set pop\n\t"
  30       : "+m"(result)
  31       :
  32       : "t0", "$f0", "$f1", "memory");
  33
  34    return (result != 0x3FF0000000000000ull);
  35 }
  36
  37 static void fatal_error(const char* msg) {
  38    fprintf(stderr, "Error: %s\n", msg);
  39    exit(1);
  40 }
  41
  42 static void test(int* fr_prctl, int* fr_detected) {
  43    *fr_prctl = prctl(PR_GET_FP_MODE);
  44    *fr_detected = get_fp_mode();
  45
  46    if (*fr_prctl < 0) {
  47       fatal_error("prctl(PR_GET_FP_MODE) fails.");
  48    }
  49
  50    printf("fr_prctl: %d, fr_detected: %d\n", *fr_prctl, *fr_detected);
  51 #if (__mips_isa_rev >= 6)
  52    if ((*fr_prctl != *fr_detected) && ((*fr_prctl != 3) || (*fr_detected != 0))) {
  53       fatal_error("fr_prctl != fr_detected");
  54    }
  55 #else
  56    if (*fr_prctl != *fr_detected) {
  57       fatal_error("fr_prctl != fr_detected");
  58    }
  59 #endif
  60 }
  61
  62 int main() {
  63    int fr_prctl, fr_detected;
  64
  65    test(&fr_prctl, &fr_detected);
  66
  67    /* FP64 */
  68    if (fr_prctl == 1) {
  69
  70 #if (__mips_isa_rev >= 6)
  71
  72       unsigned int w;
  73       unsigned long long l;
  74
  75       /* Change mode to FRE */
  76       if (prctl(PR_SET_FP_MODE, 3) != 0) {
  77          fatal_error("prctl(PR_SET_FP_MODE, 3) fails.");
  78       }
  79
  80       printf("Write to odd, read from even... ");
  81
  82       w = 0x12345678;
  83       l = 0xAAAAAAAABBBBBBBB;
  84
  85       __asm__ volatile (
  86          "ldc1 $f0, 0(%1)  \n\t"
  87          "mtc1 %0, $f1     \n\t"
  88          "sdc1 $f0, 0(%1)  \n\t"
  89          : : "r" (w), "r" (&l) : "memory", "$f0", "$f1"
  90       );
  91
  92       if (l == 0x12345678BBBBBBBBull) printf("OK\n");
  93          else printf ("Error: l = %llX\n", l);
  94
  95       printf("Write to even, read from odd... ");
  96
  97       w = 0xAAAAAAAA;
  98       l = 0x12345678AAAAAAAA;
  99
 100       __asm__ volatile (
 101          "ldc1 $f0, 0(%1)  \n\t"
 102          "mfc1 %0, $f1     \n\t"
 103          : "+r" (w) : "r" (&l) : "$f0", "$f1"
 104       );
 105
 106       if (w == 0x12345678ul) printf("OK\n");
 107          else printf ("Error: w = %X\n", w);
 108
 109       printf("Write to low part, check high part... ");
 110
 111       w = 0xBBBBBBBB;
 112       l = 0x12345678AAAAAAAA;
 113
 114       __asm__ volatile (
 115          "ldc1 $f0, 0(%1)  \n\t"
 116          "mtc1 %0, $f0     \n\t"
 117          "sdc1 $f0, 0(%1)  \n\t"
 118          : : "r" (w), "r" (&l) : "memory", "$f0"
 119       );
 120
 121       if (l == 0x12345678BBBBBBBBull) printf("OK\n");
 122          else printf ("Error: l = %llX\n", l);
 123
 124 #else
 125       /* Change mode to FP32 */
 126       if (prctl(PR_SET_FP_MODE, 0) != 0) {
 127          fatal_error("prctl(PR_SET_FP_MODE, 0) fails.");
 128       }
 129 #endif
 130       test(&fr_prctl, &fr_detected);
 131
 132       /* Change back FP mode */
 133       if (prctl(PR_SET_FP_MODE, 1) != 0) {
 134          fatal_error("prctl(PR_SET_FP_MODE, 1) fails.");
 135       }
 136
 137       test(&fr_prctl, &fr_detected);
 138    }
 139
 140    return 0;
 141 }
 142 #else
 143 int main() {
 144    return 0;
 145 }
 146 #endif