github.com/igggame/nebulas-go@v2.1.0+incompatible/nbre/3rd_party/SoftFloat-3e/source/s_shiftRightJam256M.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 <stdint.h>
    38  #include "platform.h"
    39  #include "primitiveTypes.h"
    40  
    41  #ifndef softfloat_shiftRightJam256M
    42  
    43  static
    44   void
    45    softfloat_shortShiftRightJamM(
    46        uint_fast8_t size_words,
    47        const uint64_t *aPtr,
    48        uint_fast8_t dist,
    49        uint64_t *zPtr
    50    )
    51  {
    52      uint_fast8_t uNegDist;
    53      unsigned int index, lastIndex;
    54      uint64_t partWordZ, wordA;
    55  
    56      uNegDist = -dist;
    57      index = indexWordLo( size_words );
    58      lastIndex = indexWordHi( size_words );
    59      wordA = aPtr[index];
    60      partWordZ = wordA>>dist;
    61      if ( partWordZ<<dist != wordA ) partWordZ |= 1;
    62      while ( index != lastIndex ) {
    63          wordA = aPtr[index + wordIncr];
    64          zPtr[index] = wordA<<(uNegDist & 63) | partWordZ;
    65          index += wordIncr;
    66          partWordZ = wordA>>dist;
    67      }
    68      zPtr[index] = partWordZ;
    69  
    70  }
    71  
    72  void
    73   softfloat_shiftRightJam256M(
    74       const uint64_t *aPtr, uint_fast32_t dist, uint64_t *zPtr )
    75  {
    76      uint64_t wordJam;
    77      uint_fast32_t wordDist;
    78      uint64_t *ptr;
    79      uint_fast8_t i, innerDist;
    80  
    81      wordJam = 0;
    82      wordDist = dist>>6;
    83      if ( wordDist ) {
    84          if ( 4 < wordDist ) wordDist = 4;
    85          ptr = (uint64_t *) (aPtr + indexMultiwordLo( 4, wordDist ));
    86          i = wordDist;
    87          do {
    88              wordJam = *ptr++;
    89              if ( wordJam ) break;
    90              --i;
    91          } while ( i );
    92          ptr = zPtr;
    93      }
    94      if ( wordDist < 4 ) {
    95          aPtr += indexMultiwordHiBut( 4, wordDist );
    96          innerDist = dist & 63;
    97          if ( innerDist ) {
    98              softfloat_shortShiftRightJamM(
    99                  4 - wordDist,
   100                  aPtr,
   101                  innerDist,
   102                  zPtr + indexMultiwordLoBut( 4, wordDist )
   103              );
   104              if ( ! wordDist ) goto wordJam;
   105          } else {
   106              aPtr += indexWordLo( 4 - wordDist );
   107              ptr = zPtr + indexWordLo( 4 );
   108              for ( i = 4 - wordDist; i; --i ) {
   109                  *ptr = *aPtr;
   110                  aPtr += wordIncr;
   111                  ptr += wordIncr;
   112              }
   113          }
   114          ptr = zPtr + indexMultiwordHi( 4, wordDist );
   115      }
   116      do {
   117          *ptr++ = 0;
   118          --wordDist;
   119      } while ( wordDist );
   120   wordJam:
   121      if ( wordJam ) zPtr[indexWordLo( 4 )] |= 1;
   122  
   123  }
   124  
   125  #endif
   126