github.com/igggame/nebulas-go@v2.1.0+incompatible/nbre/3rd_party/SoftFloat-3e/source/f32_to_i64.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, 2017 The Regents of the
     8  University of 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  int_fast64_t f32_to_i64( float32_t a, uint_fast8_t roundingMode, bool exact )
    45  {
    46      union ui32_f32 uA;
    47      uint_fast32_t uiA;
    48      bool sign;
    49      int_fast16_t exp;
    50      uint_fast32_t sig;
    51      int_fast16_t shiftDist;
    52  #ifdef SOFTFLOAT_FAST_INT64
    53      uint_fast64_t sig64, extra;
    54      struct uint64_extra sig64Extra;
    55  #else
    56      uint32_t extSig[3];
    57  #endif
    58  
    59      /*------------------------------------------------------------------------
    60      *------------------------------------------------------------------------*/
    61      uA.f = a;
    62      uiA = uA.ui;
    63      sign = signF32UI( uiA );
    64      exp  = expF32UI( uiA );
    65      sig  = fracF32UI( uiA );
    66      /*------------------------------------------------------------------------
    67      *------------------------------------------------------------------------*/
    68      shiftDist = 0xBE - exp;
    69      if ( shiftDist < 0 ) {
    70          softfloat_raiseFlags( softfloat_flag_invalid );
    71          return
    72              (exp == 0xFF) && sig ? i64_fromNaN
    73                  : sign ? i64_fromNegOverflow : i64_fromPosOverflow;
    74      }
    75      /*------------------------------------------------------------------------
    76      *------------------------------------------------------------------------*/
    77      if ( exp ) sig |= 0x00800000;
    78  #ifdef SOFTFLOAT_FAST_INT64
    79      sig64 = (uint_fast64_t) sig<<40;
    80      extra = 0;
    81      if ( shiftDist ) {
    82          sig64Extra = softfloat_shiftRightJam64Extra( sig64, 0, shiftDist );
    83          sig64 = sig64Extra.v;
    84          extra = sig64Extra.extra;
    85      }
    86      return softfloat_roundToI64( sign, sig64, extra, roundingMode, exact );
    87  #else
    88      extSig[indexWord( 3, 2 )] = sig<<8;
    89      extSig[indexWord( 3, 1 )] = 0;
    90      extSig[indexWord( 3, 0 )] = 0;
    91      if ( shiftDist ) softfloat_shiftRightJam96M( extSig, shiftDist, extSig );
    92      return softfloat_roundMToI64( sign, extSig, roundingMode, exact );
    93  #endif
    94  
    95  }
    96