src/math/rintf.c

   1 #include <float.h>
   2 #include <math.h>
   3 #include <stdint.h>
   4
   5 #if FLT_EVAL_METHOD==0
   6 #define EPS FLT_EPSILON
   7 #elif FLT_EVAL_METHOD==1
   8 #define EPS DBL_EPSILON
   9 #elif FLT_EVAL_METHOD==2
  10 #define EPS LDBL_EPSILON
  11 #endif
  12 static const float_t toint = 1/EPS;
  13
  14 float rintf(float x)
  15 {
  16         union {float f; uint32_t i;} u = {x};
  17         int e = u.i>>23 & 0xff;
  18         int s = u.i>>31;
  19         float_t y;
  20
  21         if (e >= 0x7f+23)
  22                 return x;
  23         if (s)
  24                 y = x - toint + toint;
  25         else
  26                 y = x + toint - toint;
  27         if (y == 0)
  28                 return s ? -0.0f : 0.0f;
  29         return y;
  30 }