softfloat/source/f128M_to_i64_r_minMag.c

   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 #include "softfloat.h"
  43
  44 #ifdef SOFTFLOAT_FAST_INT64
  45
  46 int_fast64_t f128M_to_i64_r_minMag( const float128_t *aPtr, bool exact )
  47 {
  48
  49     return f128_to_i64_r_minMag( *aPtr, exact );
  50
  51 }
  52
  53 #else
  54
  55 int_fast64_t f128M_to_i64_r_minMag( const float128_t *aPtr, bool exact )
  56 {
  57     const uint32_t *aWPtr;
  58     uint32_t uiA96;
  59     bool sign;
  60     int32_t exp;
  61     uint32_t sig96;
  62     int32_t shiftDist;
  63     uint32_t sig[4];
  64     uint64_t uiZ;
  65     union { uint64_t ui; int64_t i; } uZ;
  66
  67     /*------------------------------------------------------------------------
  68     *------------------------------------------------------------------------*/
  69     aWPtr = (const uint32_t *) aPtr;
  70     uiA96 = aWPtr[indexWordHi( 4 )];
  71     sign  = signF128UI96( uiA96 );
  72     exp   = expF128UI96( uiA96 );
  73     sig96 = fracF128UI96( uiA96 );
  74     /*------------------------------------------------------------------------
  75     *------------------------------------------------------------------------*/
  76     shiftDist = 0x403E - exp;
  77     if ( shiftDist < 0 ) goto invalid;
  78     if ( exact ) {
  79         if ( exp ) sig96 |= 0x00010000;
  80         sig[indexWord( 4, 3 )] = sig96;
  81         sig[indexWord( 4, 2 )] = aWPtr[indexWord( 4, 2 )];
  82         sig[indexWord( 4, 1 )] = aWPtr[indexWord( 4, 1 )];
  83         sig[indexWord( 4, 0 )] = aWPtr[indexWord( 4, 0 )];
  84         softfloat_shiftRightJam128M( sig, shiftDist + 17, sig );
  85         uiZ = (uint64_t) sig[indexWord( 4, 2 )]<<32 | sig[indexWord( 4, 1 )];
  86         if ( uiZ>>63 && (! sign || (uiZ != UINT64_C( 0x8000000000000000 ))) ) {
  87             goto invalid;
  88         }
  89         if ( sig[indexWordLo( 4 )] ) {
  90             softfloat_exceptionFlags |= softfloat_flag_inexact;
  91         }
  92     } else {
  93         if ( 64 <= shiftDist ) return 0;
  94         uiZ =
  95               (uint64_t) sig96<<47
  96             | (uint64_t) aWPtr[indexWord( 4, 2 )]<<15
  97             | aWPtr[indexWord( 4, 1 )]>>17;
  98         if ( shiftDist ) {
  99             uiZ |= UINT64_C( 0x8000000000000000 );
 100             uiZ >>= shiftDist;
 101         } else {
 102             if ( uiZ || ! sign ) goto invalid;
 103             uiZ |= UINT64_C( 0x8000000000000000 );
 104         }
 105     }
 106     if ( sign ) uiZ = -uiZ;
 107     uZ.ui = uiZ;
 108     return uZ.i;
 109     /*------------------------------------------------------------------------
 110     *------------------------------------------------------------------------*/
 111  invalid:
 112     softfloat_raiseFlags( softfloat_flag_invalid );
 113     return
 114         (exp == 0x7FFF)
 115             && (sig96
 116                     || (aWPtr[indexWord( 4, 2 )] | aWPtr[indexWord( 4, 1 )]
 117                             | aWPtr[indexWord( 4, 0 )]))
 118             ? i64_fromNaN
 119             : sign ? i64_fromNegOverflow : i64_fromPosOverflow;
 120
 121 }
 122
 123 #endif
 124