f32_sqrt.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
float32_t	f32_sqrt (float32_t a)

Function Documentation

f32_sqrt()

float32_t f32_sqrt

(

float32_t

a

)

Definition at line 44 of file f32_sqrt.c.

{
    union ui32_f32 uA;
    uint_fast32_t uiA;
    bool signA;
    int_fast16_t expA;
    uint_fast32_t sigA, uiZ;
    struct exp16_sig32 normExpSig;
    int_fast16_t expZ;
    uint_fast32_t sigZ, shiftedSigZ;
    uint32_t negRem;
    union ui32_f32 uZ;
 
    /*------------------------------------------------------------------------
    *------------------------------------------------------------------------*/
    uA.f = a;
    uiA = uA.ui;
    signA = signF32UI( uiA );
    expA  = expF32UI( uiA );
    sigA  = fracF32UI( uiA );
    /*------------------------------------------------------------------------
    *------------------------------------------------------------------------*/
    if ( expA == 0xFF ) {
        if ( sigA ) {
            uiZ = softfloat_propagateNaNF32UI( uiA, 0 );
            goto uiZ;
        }
        if ( ! signA ) return a;
        goto invalid;
    }
    /*------------------------------------------------------------------------
    *------------------------------------------------------------------------*/
    if ( signA ) {
        if ( ! (expA | sigA) ) return a;
        goto invalid;
    }
    /*------------------------------------------------------------------------
    *------------------------------------------------------------------------*/
    if ( ! expA ) {
        if ( ! sigA ) return a;
        normExpSig = softfloat_normSubnormalF32Sig( sigA );
        expA = normExpSig.exp;
        sigA = normExpSig.sig;
    }
    /*------------------------------------------------------------------------
    *------------------------------------------------------------------------*/
    expZ = ((expA - 0x7F)>>1) + 0x7E;
    expA &= 1;
    sigA = (sigA | 0x00800000)<<8;
    sigZ =
        ((uint_fast64_t) sigA * softfloat_approxRecipSqrt32_1( expA, sigA ))
            >>32;
    if ( expA ) sigZ >>= 1;
    /*------------------------------------------------------------------------
    *------------------------------------------------------------------------*/
    sigZ += 2;
    if ( (sigZ & 0x3F) < 2 ) {
        shiftedSigZ = sigZ>>2;
        negRem = shiftedSigZ * shiftedSigZ;
        sigZ &= ~3;
        if ( negRem & 0x80000000 ) {
            sigZ |= 1;
        } else {
            if ( negRem ) --sigZ;
        }
    }
    return softfloat_roundPackToF32( 0, expZ, sigZ );
    /*------------------------------------------------------------------------
    *------------------------------------------------------------------------*/
 invalid:
    softfloat_raiseFlags( softfloat_flag_invalid );
    uiZ = defaultNaNF32UI;
 uiZ:
    uZ.ui = uiZ;
    return uZ.f;
 
}

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