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

   1 #include "libm.h"
   2
   3 double scalbn(double x, int n)
   4 {
   5         double scale;
   6
   7         if (n > 1023) {
   8                 x *= 0x1p1023;
   9                 n -= 1023;
  10                 if (n > 1023) {
  11                         x *= 0x1p1023;
  12                         n -= 1023;
  13                         if (n > 1023)
  14                                 return x * 0x1p1023;
  15                 }
  16         } else if (n < -1022) {
  17                 x *= 0x1p-1022;
  18                 n += 1022;
  19                 if (n < -1022) {
  20                         x *= 0x1p-1022;
  21                         n += 1022;
  22                         if (n < -1022)
  23                                 return x * 0x1p-1022;
  24                 }
  25         }
  26         INSERT_WORDS(scale, (uint32_t)(0x3ff+n)<<20, 0);
  27         return x * scale;
  28 }