github.com/igggame/nebulas-go@v2.1.0+incompatible/nbre/3rd_party/SoftFloat-3e/source/extF80_mul.c (about)

     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 extF80_mul( extFloat80_t a, extFloat80_t b )
    45  {
    46      union { struct extFloat80M s; extFloat80_t f; } uA;
    47      uint_fast16_t uiA64;
    48      uint_fast64_t uiA0;
    49      bool signA;
    50      int_fast32_t expA;
    51      uint_fast64_t sigA;
    52      union { struct extFloat80M s; extFloat80_t f; } uB;
    53      uint_fast16_t uiB64;
    54      uint_fast64_t uiB0;
    55      bool signB;
    56      int_fast32_t expB;
    57      uint_fast64_t sigB;
    58      bool signZ;
    59      uint_fast64_t magBits;
    60      struct exp32_sig64 normExpSig;
    61      int_fast32_t expZ;
    62      struct uint128 sig128Z, uiZ;
    63      uint_fast16_t uiZ64;
    64      uint_fast64_t uiZ0;
    65      union { struct extFloat80M s; extFloat80_t f; } uZ;
    66  
    67      /*------------------------------------------------------------------------
    68      *------------------------------------------------------------------------*/
    69      uA.f = a;
    70      uiA64 = uA.s.signExp;
    71      uiA0  = uA.s.signif;
    72      signA = signExtF80UI64( uiA64 );
    73      expA  = expExtF80UI64( uiA64 );
    74      sigA  = uiA0;
    75      uB.f = b;
    76      uiB64 = uB.s.signExp;
    77      uiB0  = uB.s.signif;
    78      signB = signExtF80UI64( uiB64 );
    79      expB  = expExtF80UI64( uiB64 );
    80      sigB  = uiB0;
    81      signZ = signA ^ signB;
    82      /*------------------------------------------------------------------------
    83      *------------------------------------------------------------------------*/
    84      if ( expA == 0x7FFF ) {
    85          if (
    86                 (sigA & UINT64_C( 0x7FFFFFFFFFFFFFFF ))
    87              || ((expB == 0x7FFF) && (sigB & UINT64_C( 0x7FFFFFFFFFFFFFFF )))
    88          ) {
    89              goto propagateNaN;
    90          }
    91          magBits = expB | sigB;
    92          goto infArg;
    93      }
    94      if ( expB == 0x7FFF ) {
    95          if ( sigB & UINT64_C( 0x7FFFFFFFFFFFFFFF ) ) goto propagateNaN;
    96          magBits = expA | sigA;
    97          goto infArg;
    98      }
    99      /*------------------------------------------------------------------------
   100      *------------------------------------------------------------------------*/
   101      if ( ! expA ) expA = 1;
   102      if ( ! (sigA & UINT64_C( 0x8000000000000000 )) ) {
   103          if ( ! sigA ) goto zero;
   104          normExpSig = softfloat_normSubnormalExtF80Sig( sigA );
   105          expA += normExpSig.exp;
   106          sigA = normExpSig.sig;
   107      }
   108      if ( ! expB ) expB = 1;
   109      if ( ! (sigB & UINT64_C( 0x8000000000000000 )) ) {
   110          if ( ! sigB ) goto zero;
   111          normExpSig = softfloat_normSubnormalExtF80Sig( sigB );
   112          expB += normExpSig.exp;
   113          sigB = normExpSig.sig;
   114      }
   115      /*------------------------------------------------------------------------
   116      *------------------------------------------------------------------------*/
   117      expZ = expA + expB - 0x3FFE;
   118      sig128Z = softfloat_mul64To128( sigA, sigB );
   119      if ( sig128Z.v64 < UINT64_C( 0x8000000000000000 ) ) {
   120          --expZ;
   121          sig128Z =
   122              softfloat_add128(
   123                  sig128Z.v64, sig128Z.v0, sig128Z.v64, sig128Z.v0 );
   124      }
   125      return
   126          softfloat_roundPackToExtF80(
   127              signZ, expZ, sig128Z.v64, sig128Z.v0, extF80_roundingPrecision );
   128      /*------------------------------------------------------------------------
   129      *------------------------------------------------------------------------*/
   130   propagateNaN:
   131      uiZ = softfloat_propagateNaNExtF80UI( uiA64, uiA0, uiB64, uiB0 );
   132      uiZ64 = uiZ.v64;
   133      uiZ0  = uiZ.v0;
   134      goto uiZ;
   135      /*------------------------------------------------------------------------
   136      *------------------------------------------------------------------------*/
   137   infArg:
   138      if ( ! magBits ) {
   139          softfloat_raiseFlags( softfloat_flag_invalid );
   140          uiZ64 = defaultNaNExtF80UI64;
   141          uiZ0  = defaultNaNExtF80UI0;
   142      } else {
   143          uiZ64 = packToExtF80UI64( signZ, 0x7FFF );
   144          uiZ0  = UINT64_C( 0x8000000000000000 );
   145      }
   146      goto uiZ;
   147      /*------------------------------------------------------------------------
   148      *------------------------------------------------------------------------*/
   149   zero:
   150      uiZ64 = packToExtF80UI64( signZ, 0 );
   151      uiZ0  = 0;
   152   uiZ:
   153      uZ.s.signExp = uiZ64;
   154      uZ.s.signif  = uiZ0;
   155      return uZ.f;
   156  
   157  }
   158