softfloat/source/8086/s_propagateNaNExtF80UI.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, 2018 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 /*----------------------------------------------------------------------------
  45 | Interpreting the unsigned integer formed from concatenating 'uiA64' and
  46 | 'uiA0' as an 80-bit extended floating-point value, and likewise interpreting
  47 | the unsigned integer formed from concatenating 'uiB64' and 'uiB0' as another
  48 | 80-bit extended floating-point value, and assuming at least on of these
  49 | floating-point values is a NaN, returns the bit pattern of the combined NaN
  50 | result.  If either original floating-point value is a signaling NaN, the
  51 | invalid exception is raised.
  52 *----------------------------------------------------------------------------*/
  53 struct uint128
  54  softfloat_propagateNaNExtF80UI(
  55      uint_fast16_t uiA64,
  56      uint_fast64_t uiA0,
  57      uint_fast16_t uiB64,
  58      uint_fast64_t uiB0
  59  )
  60 {
  61     bool isSigNaNA, isSigNaNB;
  62     uint_fast64_t uiNonsigA0, uiNonsigB0;
  63     uint_fast16_t uiMagA64, uiMagB64;
  64     struct uint128 uiZ;
  65
  66     /*------------------------------------------------------------------------
  67     *------------------------------------------------------------------------*/
  68     isSigNaNA = softfloat_isSigNaNExtF80UI( uiA64, uiA0 );
  69     isSigNaNB = softfloat_isSigNaNExtF80UI( uiB64, uiB0 );
  70     /*------------------------------------------------------------------------
  71     | Make NaNs non-signaling.
  72     *------------------------------------------------------------------------*/
  73     uiNonsigA0 = uiA0 | UINT64_C( 0xC000000000000000 );
  74     uiNonsigB0 = uiB0 | UINT64_C( 0xC000000000000000 );
  75     /*------------------------------------------------------------------------
  76     *------------------------------------------------------------------------*/
  77     if ( isSigNaNA | isSigNaNB ) {
  78         softfloat_raiseFlags( softfloat_flag_invalid );
  79         if ( isSigNaNA ) {
  80             if ( isSigNaNB ) goto returnLargerMag;
  81             if ( isNaNExtF80UI( uiB64, uiB0 ) ) goto returnB;
  82             goto returnA;
  83         } else {
  84             if ( isNaNExtF80UI( uiA64, uiA0 ) ) goto returnA;
  85             goto returnB;
  86         }
  87     }
  88  returnLargerMag:
  89     uiMagA64 = uiA64 & 0x7FFF;
  90     uiMagB64 = uiB64 & 0x7FFF;
  91     if ( uiMagA64 < uiMagB64 ) goto returnB;
  92     if ( uiMagB64 < uiMagA64 ) goto returnA;
  93     if ( uiA0 < uiB0 ) goto returnB;
  94     if ( uiB0 < uiA0 ) goto returnA;
  95     if ( uiA64 < uiB64 ) goto returnA;
  96  returnB:
  97     uiZ.v64 = uiB64;
  98     uiZ.v0  = uiNonsigB0;
  99     return uiZ;
 100  returnA:
 101     uiZ.v64 = uiA64;
 102     uiZ.v0  = uiNonsigA0;
 103     return uiZ;
 104
 105 }
 106