github.com/igggame/nebulas-go@v2.1.0+incompatible/nbre/3rd_party/SoftFloat-3e/source/s_addMagsF128.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  
    43  float128_t
    44   softfloat_addMagsF128(
    45       uint_fast64_t uiA64,
    46       uint_fast64_t uiA0,
    47       uint_fast64_t uiB64,
    48       uint_fast64_t uiB0,
    49       bool signZ
    50   )
    51  {
    52      int_fast32_t expA;
    53      struct uint128 sigA;
    54      int_fast32_t expB;
    55      struct uint128 sigB;
    56      int_fast32_t expDiff;
    57      struct uint128 uiZ, sigZ;
    58      int_fast32_t expZ;
    59      uint_fast64_t sigZExtra;
    60      struct uint128_extra sig128Extra;
    61      union ui128_f128 uZ;
    62  
    63      expA = expF128UI64( uiA64 );
    64      sigA.v64 = fracF128UI64( uiA64 );
    65      sigA.v0  = uiA0;
    66      expB = expF128UI64( uiB64 );
    67      sigB.v64 = fracF128UI64( uiB64 );
    68      sigB.v0  = uiB0;
    69      expDiff = expA - expB;
    70      if ( ! expDiff ) {
    71          if ( expA == 0x7FFF ) {
    72              if ( sigA.v64 | sigA.v0 | sigB.v64 | sigB.v0 ) goto propagateNaN;
    73              uiZ.v64 = uiA64;
    74              uiZ.v0  = uiA0;
    75              goto uiZ;
    76          }
    77          sigZ = softfloat_add128( sigA.v64, sigA.v0, sigB.v64, sigB.v0 );
    78          if ( ! expA ) {
    79              uiZ.v64 = packToF128UI64( signZ, 0, sigZ.v64 );
    80              uiZ.v0  = sigZ.v0;
    81              goto uiZ;
    82          }
    83          expZ = expA;
    84          sigZ.v64 |= UINT64_C( 0x0002000000000000 );
    85          sigZExtra = 0;
    86          goto shiftRight1;
    87      }
    88      if ( expDiff < 0 ) {
    89          if ( expB == 0x7FFF ) {
    90              if ( sigB.v64 | sigB.v0 ) goto propagateNaN;
    91              uiZ.v64 = packToF128UI64( signZ, 0x7FFF, 0 );
    92              uiZ.v0  = 0;
    93              goto uiZ;
    94          }
    95          expZ = expB;
    96          if ( expA ) {
    97              sigA.v64 |= UINT64_C( 0x0001000000000000 );
    98          } else {
    99              ++expDiff;
   100              sigZExtra = 0;
   101              if ( ! expDiff ) goto newlyAligned;
   102          }
   103          sig128Extra =
   104              softfloat_shiftRightJam128Extra( sigA.v64, sigA.v0, 0, -expDiff );
   105          sigA = sig128Extra.v;
   106          sigZExtra = sig128Extra.extra;
   107      } else {
   108          if ( expA == 0x7FFF ) {
   109              if ( sigA.v64 | sigA.v0 ) goto propagateNaN;
   110              uiZ.v64 = uiA64;
   111              uiZ.v0  = uiA0;
   112              goto uiZ;
   113          }
   114          expZ = expA;
   115          if ( expB ) {
   116              sigB.v64 |= UINT64_C( 0x0001000000000000 );
   117          } else {
   118              --expDiff;
   119              sigZExtra = 0;
   120              if ( ! expDiff ) goto newlyAligned;
   121          }
   122          sig128Extra =
   123              softfloat_shiftRightJam128Extra( sigB.v64, sigB.v0, 0, expDiff );
   124          sigB = sig128Extra.v;
   125          sigZExtra = sig128Extra.extra;
   126      }
   127   newlyAligned:
   128      sigZ =
   129          softfloat_add128(
   130              sigA.v64 | UINT64_C( 0x0001000000000000 ),
   131              sigA.v0,
   132              sigB.v64,
   133              sigB.v0
   134          );
   135      --expZ;
   136      if ( sigZ.v64 < UINT64_C( 0x0002000000000000 ) ) goto roundAndPack;
   137      ++expZ;
   138   shiftRight1:
   139      sig128Extra =
   140          softfloat_shortShiftRightJam128Extra(
   141              sigZ.v64, sigZ.v0, sigZExtra, 1 );
   142      sigZ = sig128Extra.v;
   143      sigZExtra = sig128Extra.extra;
   144   roundAndPack:
   145      return
   146          softfloat_roundPackToF128( signZ, expZ, sigZ.v64, sigZ.v0, sigZExtra );
   147   propagateNaN:
   148      uiZ = softfloat_propagateNaNF128UI( uiA64, uiA0, uiB64, uiB0 );
   149   uiZ:
   150      uZ.ui = uiZ;
   151      return uZ.f;
   152  
   153  }
   154