softfloat/f32_mul.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 f32_mul( float32_t a, float32_t b )
  11 {
  12     union ui32_f32 uA;
  13     uint_fast32_t uiA;
  14     bool signA;
  15     int_fast16_t expA;
  16     uint_fast32_t sigA;
  17     union ui32_f32 uB;
  18     uint_fast32_t uiB;
  19     bool signB;
  20     int_fast16_t expB;
  21     uint_fast32_t sigB;
  22     bool signZ;
  23     uint_fast32_t magBits;
  24     struct exp16_sig32 normExpSig;
  25     int_fast16_t expZ;
  26     uint_fast32_t sigZ, uiZ;
  27     union ui32_f32 uZ;
  28
  29     uA.f = a;
  30     uiA = uA.ui;
  31     signA = signF32UI( uiA );
  32     expA = expF32UI( uiA );
  33     sigA = fracF32UI( uiA );
  34     uB.f = b;
  35     uiB = uB.ui;
  36     signB = signF32UI( uiB );
  37     expB = expF32UI( uiB );
  38     sigB = fracF32UI( uiB );
  39     signZ = signA ^ signB;
  40     if ( expA == 0xFF ) {
  41         if ( sigA || ( ( expB == 0xFF ) && sigB ) ) goto propagateNaN;
  42         magBits = expB | sigB;
  43         goto infArg;
  44     }
  45     if ( expB == 0xFF ) {
  46         if ( sigB ) goto propagateNaN;
  47         magBits = expA | sigA;
  48         goto infArg;
  49     }
  50     if ( ! expA ) {
  51         if ( ! sigA ) goto zero;
  52         normExpSig = softfloat_normSubnormalF32Sig( sigA );
  53         expA = normExpSig.exp;
  54         sigA = normExpSig.sig;
  55     }
  56     if ( ! expB ) {
  57         if ( ! sigB ) goto zero;
  58         normExpSig = softfloat_normSubnormalF32Sig( sigB );
  59         expB = normExpSig.exp;
  60         sigB = normExpSig.sig;
  61     }
  62     expZ = expA + expB - 0x7F;
  63     sigA = ( sigA | 0x00800000 )<<7;
  64     sigB = ( sigB | 0x00800000 )<<8;
  65     sigZ = softfloat_shortShift64RightJam( (uint_fast64_t) sigA * sigB, 32 );
  66     if ( sigZ < 0x40000000 ) {
  67         --expZ;
  68         sigZ <<= 1;
  69     }
  70     return softfloat_roundPackToF32( signZ, expZ, sigZ );
  71  propagateNaN:
  72     uiZ = softfloat_propagateNaNF32UI( uiA, uiB );
  73     goto uiZ;
  74  infArg:
  75     if ( ! magBits ) {
  76         softfloat_raiseFlags( softfloat_flag_invalid );
  77         uiZ = defaultNaNF32UI;
  78     } else {
  79         uiZ = packToF32UI( signZ, 0xFF, 0 );
  80     }
  81     goto uiZ;
  82  zero:
  83     uiZ = packToF32UI( signZ, 0, 0 );
  84  uiZ:
  85     uZ.ui = uiZ;
  86     return uZ.f;
  87
  88 }
  89