Berkeley SoftFloat fp16mul

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

float16_t f16_mul( float16_t a, float16_t b )
{
    union ui16_f16 uA;
    uint_fast16_t uiA;
    bool signA;
    int_fast8_t expA;
    uint_fast16_t sigA;
    union ui16_f16 uB;
    uint_fast16_t uiB;
    bool signB;
    int_fast8_t expB;
    uint_fast16_t sigB;
    bool signZ;
    uint_fast16_t magBits;
    struct exp8_sig16 normExpSig;
    int_fast8_t expZ;
    uint_fast32_t sig32Z;
    uint_fast16_t sigZ, uiZ;
    union ui16_f16 uZ;

    /*------------------------------------------------------------------------
    *------------------------------------------------------------------------*/
    uA.f = a;
    uiA = uA.ui;
    signA = signF16UI( uiA );
    expA  = expF16UI( uiA );
    sigA  = fracF16UI( uiA );
    uB.f = b;
    uiB = uB.ui;
    signB = signF16UI( uiB );
    expB  = expF16UI( uiB );
    sigB  = fracF16UI( uiB );
    signZ = signA ^ signB;
    /*------------------------------------------------------------------------
    *------------------------------------------------------------------------*/
    if ( expA == 0x1F ) {
        if ( sigA || ((expB == 0x1F) && sigB) ) goto propagateNaN;
        magBits = expB | sigB;
        goto infArg;
    }
    if ( expB == 0x1F ) {
        if ( sigB ) goto propagateNaN;
        magBits = expA | sigA;
        goto infArg;
    }
    /*------------------------------------------------------------------------
    *------------------------------------------------------------------------*/
    if ( ! expA ) {
        if ( ! sigA ) goto zero;
        normExpSig = softfloat_normSubnormalF16Sig( sigA );
        expA = normExpSig.exp;
        sigA = normExpSig.sig;
    }
    if ( ! expB ) {
        if ( ! sigB ) goto zero;
        normExpSig = softfloat_normSubnormalF16Sig( sigB );
        expB = normExpSig.exp;
        sigB = normExpSig.sig;
    }
    /*------------------------------------------------------------------------
    *------------------------------------------------------------------------*/
    expZ = expA + expB - 0xF;
    sigA = (sigA | 0x0400)<<4;
    sigB = (sigB | 0x0400)<<5;
    sig32Z = (uint_fast32_t) sigA * sigB;
    sigZ = sig32Z>>16;
    if ( sig32Z & 0xFFFF ) sigZ |= 1;
    if ( sigZ < 0x4000 ) {
        --expZ;
        sigZ <<= 1;
    }
    return softfloat_roundPackToF16( signZ, expZ, sigZ );
    /*------------------------------------------------------------------------
    *------------------------------------------------------------------------*/
 propagateNaN:
    uiZ = softfloat_propagateNaNF16UI( uiA, uiB );
    goto uiZ;
    /*------------------------------------------------------------------------
    *------------------------------------------------------------------------*/
 infArg:
    if ( ! magBits ) {
        softfloat_raiseFlags( softfloat_flag_invalid );
        uiZ = defaultNaNF16UI;
    } else {
        uiZ = packToF16UI( signZ, 0x1F, 0 );
    }
    goto uiZ;
    /*------------------------------------------------------------------------
    *------------------------------------------------------------------------*/
 zero:
    uiZ = packToF16UI( signZ, 0, 0 );
 uiZ:
    uZ.ui = uiZ;
    return uZ.f;

}