softfloat/source/f128M_mul.c

   1
   2 /*============================================================================
   3
   4 This C source file is part of the SoftFloat IEEE Floating-Point Arithmetic
   5 Package, Release 3e, by John R. Hauser.
   6
   7 Copyright 2011, 2012, 2013, 2014, 2015, 2016 The Regents of the University of
   8 California.  All rights reserved.
   9
  10 Redistribution and use in source and binary forms, with or without
  11 modification, are permitted provided that the following conditions are met:
  12
  13  1. Redistributions of source code must retain the above copyright notice,
  14     this list of conditions, and the following disclaimer.
  15
  16  2. Redistributions in binary form must reproduce the above copyright notice,
  17     this list of conditions, and the following disclaimer in the documentation
  18     and/or other materials provided with the distribution.
  19
  20  3. Neither the name of the University nor the names of its contributors may
  21     be used to endorse or promote products derived from this software without
  22     specific prior written permission.
  23
  24 THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS "AS IS", AND ANY
  25 EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
  26 WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE, ARE
  27 DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE FOR ANY
  28 DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
  29 (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  30 LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
  31 ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  32 (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
  33 SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  34
  35 =============================================================================*/
  36
  37 #include <stdbool.h>
  38 #include <stdint.h>
  39 #include "platform.h"
  40 #include "internals.h"
  41 #include "specialize.h"
  42 #include "softfloat.h"
  43
  44 #ifdef SOFTFLOAT_FAST_INT64
  45
  46 void
  47  f128M_mul( const float128_t *aPtr, const float128_t *bPtr, float128_t *zPtr )
  48 {
  49
  50     *zPtr = f128_mul( *aPtr, *bPtr );
  51
  52 }
  53
  54 #else
  55
  56 void
  57  f128M_mul( const float128_t *aPtr, const float128_t *bPtr, float128_t *zPtr )
  58 {
  59     const uint32_t *aWPtr, *bWPtr;
  60     uint32_t *zWPtr;
  61     uint32_t uiA96;
  62     int32_t expA;
  63     uint32_t uiB96;
  64     int32_t expB;
  65     bool signZ;
  66     const uint32_t *ptr;
  67     uint32_t uiZ96, sigA[4];
  68     uint_fast8_t shiftDist;
  69     uint32_t sigB[4];
  70     int32_t expZ;
  71     uint32_t sigProd[8], *extSigZPtr;
  72
  73     /*------------------------------------------------------------------------
  74     *------------------------------------------------------------------------*/
  75     aWPtr = (const uint32_t *) aPtr;
  76     bWPtr = (const uint32_t *) bPtr;
  77     zWPtr = (uint32_t *) zPtr;
  78     /*------------------------------------------------------------------------
  79     *------------------------------------------------------------------------*/
  80     uiA96 = aWPtr[indexWordHi( 4 )];
  81     expA = expF128UI96( uiA96 );
  82     uiB96 = bWPtr[indexWordHi( 4 )];
  83     expB = expF128UI96( uiB96 );
  84     signZ = signF128UI96( uiA96 ) ^ signF128UI96( uiB96 );
  85     /*------------------------------------------------------------------------
  86     *------------------------------------------------------------------------*/
  87     if ( (expA == 0x7FFF) || (expB == 0x7FFF) ) {
  88         if ( softfloat_tryPropagateNaNF128M( aWPtr, bWPtr, zWPtr ) ) return;
  89         ptr = aWPtr;
  90         if ( ! expA ) goto possiblyInvalid;
  91         if ( ! expB ) {
  92             ptr = bWPtr;
  93      possiblyInvalid:
  94             if (
  95                 ! fracF128UI96( ptr[indexWordHi( 4 )] )
  96                     && ! (ptr[indexWord( 4, 2 )] | ptr[indexWord( 4, 1 )]
  97                               | ptr[indexWord( 4, 0 )])
  98             ) {
  99                 softfloat_invalidF128M( zWPtr );
 100                 return;
 101             }
 102         }
 103         uiZ96 = packToF128UI96( signZ, 0x7FFF, 0 );
 104         goto uiZ96;
 105     }
 106     /*------------------------------------------------------------------------
 107     *------------------------------------------------------------------------*/
 108     if ( expA ) {
 109         sigA[indexWordHi( 4 )] = fracF128UI96( uiA96 ) | 0x00010000;
 110         sigA[indexWord( 4, 2 )] = aWPtr[indexWord( 4, 2 )];
 111         sigA[indexWord( 4, 1 )] = aWPtr[indexWord( 4, 1 )];
 112         sigA[indexWord( 4, 0 )] = aWPtr[indexWord( 4, 0 )];
 113     } else {
 114         expA = softfloat_shiftNormSigF128M( aWPtr, 0, sigA );
 115         if ( expA == -128 ) goto zero;
 116     }
 117     if ( expB ) {
 118         sigB[indexWordHi( 4 )] = fracF128UI96( uiB96 ) | 0x00010000;
 119         sigB[indexWord( 4, 2 )] = bWPtr[indexWord( 4, 2 )];
 120         sigB[indexWord( 4, 1 )] = bWPtr[indexWord( 4, 1 )];
 121         sigB[indexWord( 4, 0 )] = bWPtr[indexWord( 4, 0 )];
 122     } else {
 123         expB = softfloat_shiftNormSigF128M( bWPtr, 0, sigB );
 124         if ( expB == -128 ) goto zero;
 125     }
 126     /*------------------------------------------------------------------------
 127     *------------------------------------------------------------------------*/
 128     expZ = expA + expB - 0x4000;
 129     softfloat_mul128MTo256M( sigA, sigB, sigProd );
 130     if (
 131         sigProd[indexWord( 8, 2 )]
 132             || (sigProd[indexWord( 8, 1 )] | sigProd[indexWord( 8, 0 )])
 133     ) {
 134         sigProd[indexWord( 8, 3 )] |= 1;
 135     }
 136     extSigZPtr = &sigProd[indexMultiwordHi( 8, 5 )];
 137     shiftDist = 16;
 138     if ( extSigZPtr[indexWordHi( 5 )] & 2 ) {
 139         ++expZ;
 140         shiftDist = 15;
 141     }
 142     softfloat_shortShiftLeft160M( extSigZPtr, shiftDist, extSigZPtr );
 143     softfloat_roundPackMToF128M( signZ, expZ, extSigZPtr, zWPtr );
 144     return;
 145     /*------------------------------------------------------------------------
 146     *------------------------------------------------------------------------*/
 147  zero:
 148     uiZ96 = packToF128UI96( signZ, 0, 0 );
 149  uiZ96:
 150     zWPtr[indexWordHi( 4 )] = uiZ96;
 151     zWPtr[indexWord( 4, 2 )] = 0;
 152     zWPtr[indexWord( 4, 1 )] = 0;
 153     zWPtr[indexWord( 4, 0 )] = 0;
 154
 155 }
 156
 157 #endif
 158