github.com/igggame/nebulas-go@v2.1.0+incompatible/nbre/3rd_party/SoftFloat-3e/source/f128M_to_i64_r_minMag.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  #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