github.com/igggame/nebulas-go@v2.1.0+incompatible/nbre/3rd_party/SoftFloat-3e/source/s_addMagsExtF80.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
    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