f64_mul.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	f64_mul (float64_t a, float64_t b)

Function Documentation

f64_mul()

float64_t f64_mul	(	float64_t	a,
		float64_t	b )

Definition at line 44 of file f64_mul.c.

{
    union ui64_f64 uA;
    uint_fast64_t uiA;
    bool signA;
    int_fast16_t expA;
    uint_fast64_t sigA;
    union ui64_f64 uB;
    uint_fast64_t uiB;
    bool signB;
    int_fast16_t expB;
    uint_fast64_t sigB;
    bool signZ;
    uint_fast64_t magBits;
    struct exp16_sig64 normExpSig;
    int_fast16_t expZ;
#ifdef SOFTFLOAT_FAST_INT64
    struct uint128 sig128Z;
#else
    uint32_t sig128Z[4];
#endif
    uint_fast64_t sigZ, uiZ;
    union ui64_f64 uZ;
 
    /*------------------------------------------------------------------------
    *------------------------------------------------------------------------*/
    uA.f = a;
    uiA = uA.ui;
    signA = signF64UI( uiA );
    expA  = expF64UI( uiA );
    sigA  = fracF64UI( uiA );
    uB.f = b;
    uiB = uB.ui;
    signB = signF64UI( uiB );
    expB  = expF64UI( uiB );
    sigB  = fracF64UI( uiB );
    signZ = signA ^ signB;
    /*------------------------------------------------------------------------
    *------------------------------------------------------------------------*/
    if ( expA == 0x7FF ) {
        if ( sigA || ((expB == 0x7FF) && sigB) ) goto propagateNaN;
        magBits = expB | sigB;
        goto infArg;
    }
    if ( expB == 0x7FF ) {
        if ( sigB ) goto propagateNaN;
        magBits = expA | sigA;
        goto infArg;
    }
    /*------------------------------------------------------------------------
    *------------------------------------------------------------------------*/
    if ( ! expA ) {
        if ( ! sigA ) goto zero;
        normExpSig = softfloat_normSubnormalF64Sig( sigA );
        expA = normExpSig.exp;
        sigA = normExpSig.sig;
    }
    if ( ! expB ) {
        if ( ! sigB ) goto zero;
        normExpSig = softfloat_normSubnormalF64Sig( sigB );
        expB = normExpSig.exp;
        sigB = normExpSig.sig;
    }
    /*------------------------------------------------------------------------
    *------------------------------------------------------------------------*/
    expZ = expA + expB - 0x3FF;
    sigA = (sigA | UINT64_C( 0x0010000000000000 ))<<10;
    sigB = (sigB | UINT64_C( 0x0010000000000000 ))<<11;
#ifdef SOFTFLOAT_FAST_INT64
    sig128Z = softfloat_mul64To128( sigA, sigB );
    sigZ = sig128Z.v64 | (sig128Z.v0 != 0);
#else
    softfloat_mul64To128M( sigA, sigB, sig128Z );
    sigZ =
        (uint64_t) sig128Z[indexWord( 4, 3 )]<<32 | sig128Z[indexWord( 4, 2 )];
    if ( sig128Z[indexWord( 4, 1 )] || sig128Z[indexWord( 4, 0 )] ) sigZ |= 1;
#endif
    if ( sigZ < UINT64_C( 0x4000000000000000 ) ) {
        --expZ;
        sigZ <<= 1;
    }
    return softfloat_roundPackToF64( signZ, expZ, sigZ );
    /*------------------------------------------------------------------------
    *------------------------------------------------------------------------*/
 propagateNaN:
    uiZ = softfloat_propagateNaNF64UI( uiA, uiB );
    goto uiZ;
    /*------------------------------------------------------------------------
    *------------------------------------------------------------------------*/
 infArg:
    if ( ! magBits ) {
        softfloat_raiseFlags( softfloat_flag_invalid );
        uiZ = defaultNaNF64UI;
    } else {
        uiZ = packToF64UI( signZ, 0x7FF, 0 );
    }
    goto uiZ;
    /*------------------------------------------------------------------------
    *------------------------------------------------------------------------*/
 zero:
    uiZ = packToF64UI( signZ, 0, 0 );
 uiZ:
    uZ.ui = uiZ;
    return uZ.f;
 
}

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