nsz Git - musl/blob - src/math/scalbnf.c

   1 #include "libm.h"
   2
   3 float scalbnf(float x, int n)
   4 {
   5         float scale;
   6
   7         if (n > 127) {
   8                 x *= 0x1p127f;
   9                 n -= 127;
  10                 if (n > 127) {
  11                         x *= 0x1p127f;
  12                         n -= 127;
  13                         if (n > 127) {
  14                                 STRICT_ASSIGN(float, x, x * 0x1p127f);
  15                                 return x;
  16                         }
  17                 }
  18         } else if (n < -126) {
  19                 x *= 0x1p-126f;
  20                 n += 126;
  21                 if (n < -126) {
  22                         x *= 0x1p-126f;
  23                         n += 126;
  24                         if (n < -126) {
  25                                 STRICT_ASSIGN(float, x, x * 0x1p-126f);
  26                                 return x;
  27                         }
  28                 }
  29         }
  30         SET_FLOAT_WORD(scale, (uint32_t)(0x7f+n)<<23);
  31         STRICT_ASSIGN(float, x, x * scale);
  32         return x;
  33 }