s_subMagsF64.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
float64_t	softfloat_subMagsF64 (uint_fast64_t uiA, uint_fast64_t uiB, bool signZ)

Function Documentation

softfloat_subMagsF64()

float64_t softfloat_subMagsF64	(	uint_fast64_t	uiA,
		uint_fast64_t	uiB,
		bool	signZ )

Definition at line 45 of file s_subMagsF64.c.

{
    int_fast16_t expA;
    uint_fast64_t sigA;
    int_fast16_t expB;
    uint_fast64_t sigB;
    int_fast16_t expDiff;
    uint_fast64_t uiZ;
    int_fast64_t sigDiff;
    int_fast8_t shiftDist;
    int_fast16_t expZ;
    uint_fast64_t sigZ;
    union ui64_f64 uZ;
 
    /*------------------------------------------------------------------------
    *------------------------------------------------------------------------*/
    expA = expF64UI( uiA );
    sigA = fracF64UI( uiA );
    expB = expF64UI( uiB );
    sigB = fracF64UI( uiB );
    /*------------------------------------------------------------------------
    *------------------------------------------------------------------------*/
    expDiff = expA - expB;
    if ( ! expDiff ) {
        /*--------------------------------------------------------------------
        *--------------------------------------------------------------------*/
        if ( expA == 0x7FF ) {
            if ( sigA | sigB ) goto propagateNaN;
            softfloat_raiseFlags( softfloat_flag_invalid );
            uiZ = defaultNaNF64UI;
            goto uiZ;
        }
        sigDiff = sigA - sigB;
        if ( ! sigDiff ) {
            uiZ =
                packToF64UI(
                    (softfloat_roundingMode == softfloat_round_min), 0, 0 );
            goto uiZ;
        }
        if ( expA ) --expA;
        if ( sigDiff < 0 ) {
            signZ = ! signZ;
            sigDiff = -sigDiff;
        }
        shiftDist = softfloat_countLeadingZeros64( sigDiff ) - 11;
        expZ = expA - shiftDist;
        if ( expZ < 0 ) {
            shiftDist = expA;
            expZ = 0;
        }
        uiZ = packToF64UI( signZ, expZ, sigDiff<<shiftDist );
        goto uiZ;
    } else {
        /*--------------------------------------------------------------------
        *--------------------------------------------------------------------*/
        sigA <<= 10;
        sigB <<= 10;
        if ( expDiff < 0 ) {
            /*----------------------------------------------------------------
            *----------------------------------------------------------------*/
            signZ = ! signZ;
            if ( expB == 0x7FF ) {
                if ( sigB ) goto propagateNaN;
                uiZ = packToF64UI( signZ, 0x7FF, 0 );
                goto uiZ;
            }
            sigA += expA ? UINT64_C( 0x4000000000000000 ) : sigA;
            sigA = softfloat_shiftRightJam64( sigA, -expDiff );
            sigB |= UINT64_C( 0x4000000000000000 );
            expZ = expB;
            sigZ = sigB - sigA;
        } else {
            /*----------------------------------------------------------------
            *----------------------------------------------------------------*/
            if ( expA == 0x7FF ) {
                if ( sigA ) goto propagateNaN;
                uiZ = uiA;
                goto uiZ;
            }
            sigB += expB ? UINT64_C( 0x4000000000000000 ) : sigB;
            sigB = softfloat_shiftRightJam64( sigB, expDiff );
            sigA |= UINT64_C( 0x4000000000000000 );
            expZ = expA;
            sigZ = sigA - sigB;
        }
        return softfloat_normRoundPackToF64( signZ, expZ - 1, sigZ );
    }
    /*------------------------------------------------------------------------
    *------------------------------------------------------------------------*/
 propagateNaN:
    uiZ = softfloat_propagateNaNF64UI( uiA, uiB );
 uiZ:
    uZ.ui = uiZ;
    return uZ.f;
 
}

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