softfloat/f64_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 float64_t f64_mul( float64_t a, float64_t b )
  11 {
  12     union ui64_f64 uA;
  13     uint_fast64_t uiA;
  14     bool signA;
  15     int_fast16_t expA;
  16     uint_fast64_t sigA;
  17     union ui64_f64 uB;
  18     uint_fast64_t uiB;
  19     bool signB;
  20     int_fast16_t expB;
  21     uint_fast64_t sigB;
  22     bool signZ;
  23     uint_fast64_t magBits;
  24     struct exp16_sig64 normExpSig;
  25     int_fast16_t expZ;
  26     struct uint128 sigZ128;
  27     uint_fast64_t sigZ, uiZ;
  28     union ui64_f64 uZ;
  29
  30     uA.f = a;
  31     uiA = uA.ui;
  32     signA = signF64UI( uiA );
  33     expA = expF64UI( uiA );
  34     sigA = fracF64UI( uiA );
  35     uB.f = b;
  36     uiB = uB.ui;
  37     signB = signF64UI( uiB );
  38     expB = expF64UI( uiB );
  39     sigB = fracF64UI( uiB );
  40     signZ = signA ^ signB;
  41     if ( expA == 0x7FF ) {
  42         if ( sigA || ( ( expB == 0x7FF ) && sigB ) ) goto propagateNaN;
  43         magBits = expB | sigB;
  44         goto infArg;
  45     }
  46     if ( expB == 0x7FF ) {
  47         if ( sigB ) goto propagateNaN;
  48         magBits = expA | sigA;
  49         goto infArg;
  50     }
  51     if ( ! expA ) {
  52         if ( ! sigA ) goto zero;
  53         normExpSig = softfloat_normSubnormalF64Sig( sigA );
  54         expA = normExpSig.exp;
  55         sigA = normExpSig.sig;
  56     }
  57     if ( ! expB ) {
  58         if ( ! sigB ) goto zero;
  59         normExpSig = softfloat_normSubnormalF64Sig( sigB );
  60         expB = normExpSig.exp;
  61         sigB = normExpSig.sig;
  62     }
  63     expZ = expA + expB - 0x3FF;
  64     sigA = ( sigA | UINT64_C( 0x0010000000000000 ) )<<10;
  65     sigB = ( sigB | UINT64_C( 0x0010000000000000 ) )<<11;
  66     sigZ128 = softfloat_mul64To128( sigA, sigB );
  67     sigZ = sigZ128.v64 | ( sigZ128.v0 != 0 );
  68     if ( sigZ < UINT64_C( 0x4000000000000000 ) ) {
  69         --expZ;
  70         sigZ <<= 1;
  71     }
  72     return softfloat_roundPackToF64( signZ, expZ, sigZ );
  73  propagateNaN:
  74     uiZ = softfloat_propagateNaNF64UI( uiA, uiB );
  75     goto uiZ;
  76  infArg:
  77     if ( ! magBits ) {
  78         softfloat_raiseFlags( softfloat_flag_invalid );
  79         uiZ = defaultNaNF64UI;
  80     } else {
  81         uiZ = packToF64UI( signZ, 0x7FF, 0 );
  82     }
  83     goto uiZ;
  84  zero:
  85     uiZ = packToF64UI( signZ, 0, 0 );
  86  uiZ:
  87     uZ.ui = uiZ;
  88     return uZ.f;
  89
  90 }
  91