f64_div.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_div (float64_t a, float64_t b)

Function Documentation

f64_div()

float64_t f64_div	(	float64_t	a,
		float64_t	b )

Definition at line 44 of file f64_div.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;
    struct exp16_sig64 normExpSig;
    int_fast16_t expZ;
    uint32_t recip32, sig32Z, doubleTerm;
    uint_fast64_t rem;
    uint32_t q;
    uint_fast64_t sigZ;
    uint_fast64_t 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 ) goto propagateNaN;
        if ( expB == 0x7FF ) {
            if ( sigB ) goto propagateNaN;
            goto invalid;
        }
        goto infinity;
    }
    if ( expB == 0x7FF ) {
        if ( sigB ) goto propagateNaN;
        goto zero;
    }
    /*------------------------------------------------------------------------
    *------------------------------------------------------------------------*/
    if ( ! expB ) {
        if ( ! sigB ) {
            if ( ! (expA | sigA) ) goto invalid;
            softfloat_raiseFlags( softfloat_flag_infinite );
            goto infinity;
        }
        normExpSig = softfloat_normSubnormalF64Sig( sigB );
        expB = normExpSig.exp;
        sigB = normExpSig.sig;
    }
    if ( ! expA ) {
        if ( ! sigA ) goto zero;
        normExpSig = softfloat_normSubnormalF64Sig( sigA );
        expA = normExpSig.exp;
        sigA = normExpSig.sig;
    }
    /*------------------------------------------------------------------------
    *------------------------------------------------------------------------*/
    expZ = expA - expB + 0x3FE;
    sigA |= UINT64_C( 0x0010000000000000 );
    sigB |= UINT64_C( 0x0010000000000000 );
    if ( sigA < sigB ) {
        --expZ;
        sigA <<= 11;
    } else {
        sigA <<= 10;
    }
    sigB <<= 11;
    recip32 = softfloat_approxRecip32_1( sigB>>32 ) - 2;
    sig32Z = ((uint32_t) (sigA>>32) * (uint_fast64_t) recip32)>>32;
    doubleTerm = sig32Z<<1;
    rem =
        ((sigA - (uint_fast64_t) doubleTerm * (uint32_t) (sigB>>32))<<28)
            - (uint_fast64_t) doubleTerm * ((uint32_t) sigB>>4);
    q = (((uint32_t) (rem>>32) * (uint_fast64_t) recip32)>>32) + 4;
    sigZ = ((uint_fast64_t) sig32Z<<32) + ((uint_fast64_t) q<<4);
    /*------------------------------------------------------------------------
    *------------------------------------------------------------------------*/
    if ( (sigZ & 0x1FF) < 4<<4 ) {
        q &= ~7;
        sigZ &= ~(uint_fast64_t) 0x7F;
        doubleTerm = q<<1;
        rem =
            ((rem - (uint_fast64_t) doubleTerm * (uint32_t) (sigB>>32))<<28)
                - (uint_fast64_t) doubleTerm * ((uint32_t) sigB>>4);
        if ( rem & UINT64_C( 0x8000000000000000 ) ) {
            sigZ -= 1<<7;
        } else {
            if ( rem ) sigZ |= 1;
        }
    }
    return softfloat_roundPackToF64( signZ, expZ, sigZ );
    /*------------------------------------------------------------------------
    *------------------------------------------------------------------------*/
 propagateNaN:
    uiZ = softfloat_propagateNaNF64UI( uiA, uiB );
    goto uiZ;
    /*------------------------------------------------------------------------
    *------------------------------------------------------------------------*/
 invalid:
    softfloat_raiseFlags( softfloat_flag_invalid );
    uiZ = defaultNaNF64UI;
    goto uiZ;
    /*------------------------------------------------------------------------
    *------------------------------------------------------------------------*/
 infinity:
    uiZ = packToF64UI( signZ, 0x7FF, 0 );
    goto uiZ;
    /*------------------------------------------------------------------------
    *------------------------------------------------------------------------*/
 zero:
    uiZ = packToF64UI( signZ, 0, 0 );
 uiZ:
    uZ.ui = uiZ;
    return uZ.f;
 
}

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