softfloat/s_shiftRightJam256M.c

   1
   2 /*============================================================================
   3
   4 This C source file is part of the SoftFloat IEEE Floating-Point Arithmetic
   5 Package, Release 3d, 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