s_remStepMBy32.c

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/*============================================================================
 
This C source file is part of the SoftFloat IEEE Floating-Point Arithmetic
Package, Release 3e, by John R. Hauser.
 
Copyright 2011, 2012, 2013, 2014, 2015, 2016 The Regents of the University of
California.  All rights reserved.
 
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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
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 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
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(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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=============================================================================*/
 
#include <stdint.h>
#include "platform.h"
#include "primitiveTypes.h"
 
#ifndef softfloat_remStepMBy32
 
void
 softfloat_remStepMBy32(
     uint_fast8_t size_words,
     const uint32_t *remPtr,
     uint_fast8_t dist,
     const uint32_t *bPtr,
     uint32_t q,
     uint32_t *zPtr
 )
{
    unsigned int index, lastIndex;
    uint64_t dwordProd;
    uint32_t wordRem, wordShiftedRem, wordProd;
    uint_fast8_t uNegDist, borrow;
 
    index = indexWordLo( size_words );
    lastIndex = indexWordHi( size_words );
    dwordProd = (uint64_t) bPtr[index] * q;
    wordRem = remPtr[index];
    wordShiftedRem = wordRem<<dist;
    wordProd = dwordProd;
    zPtr[index] = wordShiftedRem - wordProd;
    if ( index != lastIndex ) {
        uNegDist = -dist;
        borrow = (wordShiftedRem < wordProd);
        for (;;) {
            wordShiftedRem = wordRem>>(uNegDist & 31);
            index += wordIncr;
            dwordProd = (uint64_t) bPtr[index] * q + (dwordProd>>32);
            wordRem = remPtr[index];
            wordShiftedRem |= wordRem<<dist;
            wordProd = dwordProd;
            zPtr[index] = wordShiftedRem - wordProd - borrow;
            if ( index == lastIndex ) break;
            borrow =
                borrow ? (wordShiftedRem <= wordProd)
                    : (wordShiftedRem < wordProd);
        }
    }
 
}
 
#endif