softfloat/source/s_addMagsExtF80.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 The Regents of the University of California.
   8 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 extFloat80_t
  45  softfloat_addMagsExtF80(
  46      uint_fast16_t uiA64,
  47      uint_fast64_t uiA0,
  48      uint_fast16_t uiB64,
  49      uint_fast64_t uiB0,
  50      bool signZ
  51  )
  52 {
  53     int_fast32_t expA;
  54     uint_fast64_t sigA;
  55     int_fast32_t expB;
  56     uint_fast64_t sigB;
  57     int_fast32_t expDiff;
  58     uint_fast16_t uiZ64;
  59     uint_fast64_t uiZ0, sigZ, sigZExtra;
  60     struct exp32_sig64 normExpSig;
  61     int_fast32_t expZ;
  62     struct uint64_extra sig64Extra;
  63     struct uint128 uiZ;
  64     union { struct extFloat80M s; extFloat80_t f; } uZ;
  65
  66     /*------------------------------------------------------------------------
  67     *------------------------------------------------------------------------*/
  68     expA = expExtF80UI64( uiA64 );
  69     sigA = uiA0;
  70     expB = expExtF80UI64( uiB64 );
  71     sigB = uiB0;
  72     /*------------------------------------------------------------------------
  73     *------------------------------------------------------------------------*/
  74     expDiff = expA - expB;
  75     if ( ! expDiff ) {
  76         if ( expA == 0x7FFF ) {
  77             if ( (sigA | sigB) & UINT64_C( 0x7FFFFFFFFFFFFFFF ) ) {
  78                 goto propagateNaN;
  79             }
  80             uiZ64 = uiA64;
  81             uiZ0  = uiA0;
  82             goto uiZ;
  83         }
  84         sigZ = sigA + sigB;
  85         sigZExtra = 0;
  86         if ( ! expA ) {
  87             normExpSig = softfloat_normSubnormalExtF80Sig( sigZ );
  88             expZ = normExpSig.exp + 1;
  89             sigZ = normExpSig.sig;
  90             goto roundAndPack;
  91         }
  92         expZ = expA;
  93         goto shiftRight1;
  94     }
  95     /*------------------------------------------------------------------------
  96     *------------------------------------------------------------------------*/
  97     if ( expDiff < 0 ) {
  98         if ( expB == 0x7FFF ) {
  99             if ( sigB & UINT64_C( 0x7FFFFFFFFFFFFFFF ) ) goto propagateNaN;
 100             uiZ64 = packToExtF80UI64( signZ, 0x7FFF );
 101             uiZ0  = uiB0;
 102             goto uiZ;
 103         }
 104         expZ = expB;
 105         if ( ! expA ) {
 106             ++expDiff;
 107             sigZExtra = 0;
 108             if ( ! expDiff ) goto newlyAligned;
 109         }
 110         sig64Extra = softfloat_shiftRightJam64Extra( sigA, 0, -expDiff );
 111         sigA = sig64Extra.v;
 112         sigZExtra = sig64Extra.extra;
 113     } else {
 114         if ( expA == 0x7FFF ) {
 115             if ( sigA & UINT64_C( 0x7FFFFFFFFFFFFFFF ) ) goto propagateNaN;
 116             uiZ64 = uiA64;
 117             uiZ0  = uiA0;
 118             goto uiZ;
 119         }
 120         expZ = expA;
 121         if ( ! expB ) {
 122             --expDiff;
 123             sigZExtra = 0;
 124             if ( ! expDiff ) goto newlyAligned;
 125         }
 126         sig64Extra = softfloat_shiftRightJam64Extra( sigB, 0, expDiff );
 127         sigB = sig64Extra.v;
 128         sigZExtra = sig64Extra.extra;
 129     }
 130  newlyAligned:
 131     sigZ = sigA + sigB;
 132     if ( sigZ & UINT64_C( 0x8000000000000000 ) ) goto roundAndPack;
 133     /*------------------------------------------------------------------------
 134     *------------------------------------------------------------------------*/
 135  shiftRight1:
 136     sig64Extra = softfloat_shortShiftRightJam64Extra( sigZ, sigZExtra, 1 );
 137     sigZ = sig64Extra.v | UINT64_C( 0x8000000000000000 );
 138     sigZExtra = sig64Extra.extra;
 139     ++expZ;
 140  roundAndPack:
 141     return
 142         softfloat_roundPackToExtF80(
 143             signZ, expZ, sigZ, sigZExtra, extF80_roundingPrecision );
 144     /*------------------------------------------------------------------------
 145     *------------------------------------------------------------------------*/
 146  propagateNaN:
 147     uiZ = softfloat_propagateNaNExtF80UI( uiA64, uiA0, uiB64, uiB0 );
 148     uiZ64 = uiZ.v64;
 149     uiZ0  = uiZ.v0;
 150  uiZ:
 151     uZ.s.signExp = uiZ64;
 152     uZ.s.signif  = uiZ0;
 153     return uZ.f;
 154
 155 }
 156