github.com/igggame/nebulas-go@v2.1.0+incompatible/nbre/3rd_party/SoftFloat-3e/source/s_addMagsF64.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, 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  
    43  float64_t
    44   softfloat_addMagsF64( uint_fast64_t uiA, uint_fast64_t uiB, bool signZ )
    45  {
    46      int_fast16_t expA;
    47      uint_fast64_t sigA;
    48      int_fast16_t expB;
    49      uint_fast64_t sigB;
    50      int_fast16_t expDiff;
    51      uint_fast64_t uiZ;
    52      int_fast16_t expZ;
    53      uint_fast64_t sigZ;
    54      union ui64_f64 uZ;
    55  
    56      /*------------------------------------------------------------------------
    57      *------------------------------------------------------------------------*/
    58      expA = expF64UI( uiA );
    59      sigA = fracF64UI( uiA );
    60      expB = expF64UI( uiB );
    61      sigB = fracF64UI( uiB );
    62      /*------------------------------------------------------------------------
    63      *------------------------------------------------------------------------*/
    64      expDiff = expA - expB;
    65      if ( ! expDiff ) {
    66          /*--------------------------------------------------------------------
    67          *--------------------------------------------------------------------*/
    68          if ( ! expA ) {
    69              uiZ = uiA + sigB;
    70              goto uiZ;
    71          }
    72          if ( expA == 0x7FF ) {
    73              if ( sigA | sigB ) goto propagateNaN;
    74              uiZ = uiA;
    75              goto uiZ;
    76          }
    77          expZ = expA;
    78          sigZ = UINT64_C( 0x0020000000000000 ) + sigA + sigB;
    79          sigZ <<= 9;
    80      } else {
    81          /*--------------------------------------------------------------------
    82          *--------------------------------------------------------------------*/
    83          sigA <<= 9;
    84          sigB <<= 9;
    85          if ( expDiff < 0 ) {
    86              if ( expB == 0x7FF ) {
    87                  if ( sigB ) goto propagateNaN;
    88                  uiZ = packToF64UI( signZ, 0x7FF, 0 );
    89                  goto uiZ;
    90              }
    91              expZ = expB;
    92              if ( expA ) {
    93                  sigA += UINT64_C( 0x2000000000000000 );
    94              } else {
    95                  sigA <<= 1;
    96              }
    97              sigA = softfloat_shiftRightJam64( sigA, -expDiff );
    98          } else {
    99              if ( expA == 0x7FF ) {
   100                  if ( sigA ) goto propagateNaN;
   101                  uiZ = uiA;
   102                  goto uiZ;
   103              }
   104              expZ = expA;
   105              if ( expB ) {
   106                  sigB += UINT64_C( 0x2000000000000000 );
   107              } else {
   108                  sigB <<= 1;
   109              }
   110              sigB = softfloat_shiftRightJam64( sigB, expDiff );
   111          }
   112          sigZ = UINT64_C( 0x2000000000000000 ) + sigA + sigB;
   113          if ( sigZ < UINT64_C( 0x4000000000000000 ) ) {
   114              --expZ;
   115              sigZ <<= 1;
   116          }
   117      }
   118      return softfloat_roundPackToF64( signZ, expZ, sigZ );
   119      /*------------------------------------------------------------------------
   120      *------------------------------------------------------------------------*/
   121   propagateNaN:
   122      uiZ = softfloat_propagateNaNF64UI( uiA, uiB );
   123   uiZ:
   124      uZ.ui = uiZ;
   125      return uZ.f;
   126  
   127  }
   128