text: 
  /*============================================================================
  
  This C source file is part of the SoftFloat IEEE Floating-Point Arithmetic
  Package, Release 3a, by John R. Hauser.
  
  Copyright 2011, 2012, 2013, 2014 The Regents of the University of California.
  All rights reserved.
  
  Redistribution and use in source and binary forms, with or without
  modification, are permitted provided that the following conditions are met:
  
   1. Redistributions of source code must retain the above copyright notice,
      this list of conditions, and the following disclaimer.
  
   2. Redistributions in binary form must reproduce the above copyright notice,
      this list of conditions, and the following disclaimer in the documentation
      and/or other materials provided with the distribution.
  
   3. Neither the name of the University nor the names of its contributors may
      be used to endorse or promote products derived from this software without
      specific prior written permission.
  
  THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS "AS IS", AND ANY
  EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
  WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE, ARE
  DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE FOR ANY
  DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
  (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
  ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
  SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  
  =============================================================================*/
  
  /*============================================================================
  Modifications to comply with IBM IEEE Binary Floating Point, as defined
  in the z/Architecture Principles of Operation, SA22-7832-10, by
  Stephen R. Orso.  Said modifications identified by compilation conditioned
  on preprocessor variable IBM_IEEE.
  All such modifications placed in the public domain by Stephen R. Orso
  Modifications:
   1) Replaced NaN propagation rules with those required to conform to
      SA22-7832-10.  Multiple figures describe these rules; see Figure 19-13
      on page 19-13 for the description for the Add instruction.
  =============================================================================*/
  
  #include "platform.h" 
  #include "internals.h"
  #include "specialize.h"
  #include "softfloat.h"
  
  /*----------------------------------------------------------------------------
  | Interpreting the unsigned integer formed from concatenating `uiA64' and
  | `uiA0' as a 128-bit floating-point value, and likewise interpreting the
  | unsigned integer formed from concatenating `uiB64' and `uiB0' as another
  | 128-bit floating-point value, and assuming at least on of these floating-
  | point values is a NaN, returns the bit pattern of the combined NaN result.
  | If either original floating-point value is a signaling NaN, the invalid
  | exception is raised.
  *----------------------------------------------------------------------------*/
  
  #ifdef IBM_IEEE
  /*----------------------------------------------------------------------------
  | Note: Above comment is incorrect whether compiled for the IBM_IEEE case
  | or the default case.  Under no circumstances are the payloads combined.
  | Only one of the two payloads is propagated.
  *----------------------------------------------------------------------------*/
  #endif
  
  struct uint128
   softfloat_propagateNaNF128UI(
       uint_fast64_t uiA64,
       uint_fast64_t uiA0,
       uint_fast64_t uiB64,
       uint_fast64_t uiB0
   )
  {
  #ifdef IBM_IEEE         /* IBM NaN propagation rules defined (consistently) in many tables      */
                          /* in SA22-7832-10; see for example Table 19-13 on page 19-16.          */
                          /* In short:                                                            */
                          /*    If A is SNaN, return QNaN(A)                                      */
                          /*    If B is SNaN, return QNaN(B)                                      */
                          /*    If A is QNaN, return A                                            */
                          /*    If B is QNaN, return B                                            */
  
      bool isSigNaNA;
      bool isSigNaNB;
      struct uint128 uiZ;
  
      isSigNaNA = softfloat_isSigNaNF128UI(uiA64, uiA0);
      isSigNaNB = softfloat_isSigNaNF128UI(uiB64, uiB0);
      if (isSigNaNA || isSigNaNB)
          softfloat_raiseFlags(softfloat_flag_invalid);
      if (isSigNaNA || (!isSigNaNB  && isNaNF128UI(uiA64, uiA0))) {
          uiZ.v64 = uiA64;
          uiZ.v0 = uiA0;
      }
      else {
          uiZ.v64 = uiB64;
          uiZ.v0 = uiB0;
      }
      uiZ.v64 |= UINT64_C(0x0000800000000000);
      return uiZ;
  
  #else
      bool isSigNaNA;
      struct uint128 uiZ;
  
      isSigNaNA = softfloat_isSigNaNF128UI( uiA64, uiA0 );
      if ( isSigNaNA || softfloat_isSigNaNF128UI( uiB64, uiB0 ) ) {
          softfloat_raiseFlags( softfloat_flag_invalid );
          if ( isSigNaNA ) goto returnNonsigA;
      }
      if ( isNaNF128UI( uiA64, uiA0 ) ) {
   returnNonsigA:
          uiZ.v64 = uiA64;
          uiZ.v0  = uiA0;
      } else {
          uiZ.v64 = uiB64;
          uiZ.v0  = uiB0;
      }
      uiZ.v64 |= UINT64_C( 0x0000800000000000 );
      return uiZ;
  
  #endif
  
  }
  
  