softfloat/f64_to_f32.c

   1
   2 #include <stdbool.h>
   3 #include <stdint.h>
   4 #include "platform.h"
   5 #include "primitives.h"
   6 #include "internals.h"
   7 #include "specialize.h"
   8 #include "softfloat.h"
   9
  10 float32_t f64_to_f32( float64_t a )
  11 {
  12     union ui64_f64 uA;
  13     uint_fast64_t uiA;
  14     bool sign;
  15     int_fast16_t exp;
  16     uint_fast64_t sig;
  17     uint_fast32_t uiZ, sig32;
  18     union ui32_f32 uZ;
  19
  20     uA.f = a;
  21     uiA = uA.ui;
  22     sign = signF64UI( uiA );
  23     exp = expF64UI( uiA );
  24     sig = fracF64UI( uiA );
  25     if ( exp == 0x7FF ) {
  26         uiZ =
  27             sig ? softfloat_commonNaNToF32UI(
  28                       softfloat_f64UIToCommonNaN( uiA ) )
  29                 : packToF32UI( sign, 0xFF, 0 );
  30         goto uiZ;
  31     }
  32     sig32 = softfloat_shortShift64RightJam( sig, 22 );
  33     if ( ! ( exp | sig32 ) ) {
  34         uiZ = packToF32UI( sign, 0, 0 );
  35         goto uiZ;
  36     }
  37     return softfloat_roundPackToF32( sign, exp - 0x381, sig32 | 0x40000000 );
  38  uiZ:
  39     uZ.ui = uiZ;
  40     return uZ.f;
  41
  42 }
  43