extF80M_rem.c File Reference

#include <stdbool.h>
#include <stdint.h>
#include "platform.h"
#include "internals.h"
#include "specialize.h"
#include "softfloat.h"

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Functions
void	extF80M_rem (const extFloat80_t *aPtr, const extFloat80_t *bPtr, extFloat80_t *zPtr)

Function Documentation

extF80M_rem()

void extF80M_rem	(	const extFloat80_t *	aPtr,
		const extFloat80_t *	bPtr,
		extFloat80_t *	zPtr )

Definition at line 58 of file extF80M_rem.c.

{
    const struct extFloat80M *aSPtr, *bSPtr;
    struct extFloat80M *zSPtr;
    uint_fast16_t uiA64;
    int32_t expA, expB;
    uint64_t x64;
    bool signRem;
    uint64_t sigA;
    int32_t expDiff;
    uint32_t rem[3], x[3], sig32B, q, recip32, rem2[3], *remPtr, *altRemPtr;
    uint32_t *newRemPtr, wordMeanRem;
 
    /*------------------------------------------------------------------------
    *------------------------------------------------------------------------*/
    aSPtr = (const struct extFloat80M *) aPtr;
    bSPtr = (const struct extFloat80M *) bPtr;
    zSPtr = (struct extFloat80M *) zPtr;
    /*------------------------------------------------------------------------
    *------------------------------------------------------------------------*/
    uiA64 = aSPtr->signExp;
    expA = expExtF80UI64( uiA64 );
    expB = expExtF80UI64( bSPtr->signExp );
    /*------------------------------------------------------------------------
    *------------------------------------------------------------------------*/
    if ( (expA == 0x7FFF) || (expB == 0x7FFF) ) {
        if ( softfloat_tryPropagateNaNExtF80M( aSPtr, bSPtr, zSPtr ) ) return;
        if ( expA == 0x7FFF ) goto invalid;
        /*--------------------------------------------------------------------
        | If we get here, then argument b is an infinity and `expB' is 0x7FFF;
        | Doubling `expB' is an easy way to ensure that `expDiff' later is
        | less than -1, which will result in returning a canonicalized version
        | of argument a.
        *--------------------------------------------------------------------*/
        expB += expB;
    }
    /*------------------------------------------------------------------------
    *------------------------------------------------------------------------*/
    if ( ! expB ) expB = 1;
    x64 = bSPtr->signif;
    if ( ! (x64 & UINT64_C( 0x8000000000000000 )) ) {
        if ( ! x64 ) goto invalid;
        expB += softfloat_normExtF80SigM( &x64 );
    }
    signRem = signExtF80UI64( uiA64 );
    if ( ! expA ) expA = 1;
    sigA = aSPtr->signif;
    if ( ! (sigA & UINT64_C( 0x8000000000000000 )) ) {
        if ( ! sigA ) {
            expA = 0;
            goto copyA;
        }
        expA += softfloat_normExtF80SigM( &sigA );
    }
    /*------------------------------------------------------------------------
    *------------------------------------------------------------------------*/
    expDiff = expA - expB;
    if ( expDiff < -1 ) goto copyA;
    rem[indexWord( 3, 2 )] = sigA>>34;
    rem[indexWord( 3, 1 )] = sigA>>2;
    rem[indexWord( 3, 0 )] = (uint32_t) sigA<<30;
    x[indexWord( 3, 0 )] = (uint32_t) x64<<30;
    sig32B = x64>>32;
    x64 >>= 2;
    x[indexWord( 3, 2 )] = x64>>32;
    x[indexWord( 3, 1 )] = x64;
    if ( expDiff < 1 ) {
        if ( expDiff ) {
            --expB;
            softfloat_add96M( x, x, x );
            q = 0;
        } else {
            q = (softfloat_compare96M( x, rem ) <= 0);
            if ( q ) softfloat_sub96M( rem, x, rem );
        }
    } else {
        recip32 = softfloat_approxRecip32_1( sig32B );
        expDiff -= 30;
        for (;;) {
            x64 = (uint64_t) rem[indexWordHi( 3 )] * recip32;
            if ( expDiff < 0 ) break;
            q = (x64 + 0x80000000)>>32;
            softfloat_remStep96MBy32( rem, 29, x, q, rem );
            if ( rem[indexWordHi( 3 )] & 0x80000000 ) {
                softfloat_add96M( rem, x, rem );
            }
            expDiff -= 29;
        }
        /*--------------------------------------------------------------------
        | (`expDiff' cannot be less than -29 here.)
        *--------------------------------------------------------------------*/
        q = (uint32_t) (x64>>32)>>(~expDiff & 31);
        softfloat_remStep96MBy32( rem, expDiff + 30, x, q, rem );
        if ( rem[indexWordHi( 3 )] & 0x80000000 ) {
            remPtr = rem;
            altRemPtr = rem2;
            softfloat_add96M( remPtr, x, altRemPtr );
            goto selectRem;
        }
    }
    /*------------------------------------------------------------------------
    *------------------------------------------------------------------------*/
    remPtr = rem;
    altRemPtr = rem2;
    do {
        ++q;
        newRemPtr = altRemPtr;
        softfloat_sub96M( remPtr, x, newRemPtr );
        altRemPtr = remPtr;
        remPtr = newRemPtr;
    } while ( ! (remPtr[indexWordHi( 3 )] & 0x80000000) );
 selectRem:
    softfloat_add96M( remPtr, altRemPtr, x );
    wordMeanRem = x[indexWordHi( 3 )];
    if (
        (wordMeanRem & 0x80000000)
            || (! wordMeanRem && (q & 1) && ! x[indexWord( 3, 0 )]
                    && ! x[indexWord( 3, 1 )])
    ) {
        remPtr = altRemPtr;
    }
    if ( remPtr[indexWordHi( 3 )] & 0x80000000 ) {
        signRem = ! signRem;
        softfloat_negX96M( remPtr );
    }
    softfloat_normRoundPackMToExtF80M( signRem, expB + 2, remPtr, 80, zSPtr );
    return;
    /*------------------------------------------------------------------------
    *------------------------------------------------------------------------*/
 invalid:
    softfloat_invalidExtF80M( zSPtr );
    return;
    /*------------------------------------------------------------------------
    *------------------------------------------------------------------------*/
 copyA:
    if ( expA < 1 ) {
        sigA >>= 1 - expA;
        expA = 0;
    }
    zSPtr->signExp = packToExtF80UI64( signRem, expA );
    zSPtr->signif = sigA;
 
}

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