f128_roundToInt.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
float128_t	f128_roundToInt (float128_t a, uint_fast8_t roundingMode, bool exact)

Function Documentation

f128_roundToInt()

float128_t f128_roundToInt	(	float128_t	a,
		uint_fast8_t	roundingMode,
		bool	exact )

Definition at line 45 of file f128_roundToInt.c.

{
    union ui128_f128 uA;
    uint_fast64_t uiA64, uiA0;
    int_fast32_t exp;
    struct uint128 uiZ;
    uint_fast64_t lastBitMask0, roundBitsMask;
    bool roundNearEven;
    uint_fast64_t lastBitMask64;
    union ui128_f128 uZ;
 
    /*------------------------------------------------------------------------
    *------------------------------------------------------------------------*/
    uA.f = a;
    uiA64 = uA.ui.v64;
    uiA0  = uA.ui.v0;
    exp = expF128UI64( uiA64 );
    /*------------------------------------------------------------------------
    *------------------------------------------------------------------------*/
    if ( 0x402F <= exp ) {
        /*--------------------------------------------------------------------
        *--------------------------------------------------------------------*/
        if ( 0x406F <= exp ) {
            if ( (exp == 0x7FFF) && (fracF128UI64( uiA64 ) | uiA0) ) {
                uiZ = softfloat_propagateNaNF128UI( uiA64, uiA0, 0, 0 );
                goto uiZ;
            }
            return a;
        }
        /*--------------------------------------------------------------------
        *--------------------------------------------------------------------*/
        lastBitMask0 = (uint_fast64_t) 2<<(0x406E - exp);
        roundBitsMask = lastBitMask0 - 1;
        uiZ.v64 = uiA64;
        uiZ.v0  = uiA0;
        roundNearEven = (roundingMode == softfloat_round_near_even);
        if ( roundNearEven || (roundingMode == softfloat_round_near_maxMag) ) {
            if ( exp == 0x402F ) {
                if ( UINT64_C( 0x8000000000000000 ) <= uiZ.v0 ) {
                    ++uiZ.v64;
                    if (
                        roundNearEven
                            && (uiZ.v0 == UINT64_C( 0x8000000000000000 ))
                    ) {
                        uiZ.v64 &= ~1;
                    }
                }
            } else {
                uiZ = softfloat_add128( uiZ.v64, uiZ.v0, 0, lastBitMask0>>1 );
                if ( roundNearEven && !(uiZ.v0 & roundBitsMask) ) {
                    uiZ.v0 &= ~lastBitMask0;
                }
            }
        } else if (
            roundingMode
                == (signF128UI64( uiZ.v64 ) ? softfloat_round_min
                        : softfloat_round_max)
        ) {
            uiZ = softfloat_add128( uiZ.v64, uiZ.v0, 0, roundBitsMask );
        }
        uiZ.v0 &= ~roundBitsMask;
        lastBitMask64 = !lastBitMask0;
    } else {
        /*--------------------------------------------------------------------
        *--------------------------------------------------------------------*/
        if ( exp < 0x3FFF ) {
            if ( !((uiA64 & UINT64_C( 0x7FFFFFFFFFFFFFFF )) | uiA0) ) return a;
            if ( exact ) softfloat_exceptionFlags |= softfloat_flag_inexact;
            uiZ.v64 = uiA64 & packToF128UI64( 1, 0, 0 );
            uiZ.v0  = 0;
            switch ( roundingMode ) {
             case softfloat_round_near_even:
                if ( !(fracF128UI64( uiA64 ) | uiA0) ) break;
             case softfloat_round_near_maxMag:
                if ( exp == 0x3FFE ) uiZ.v64 |= packToF128UI64( 0, 0x3FFF, 0 );
                break;
             case softfloat_round_min:
                if ( uiZ.v64 ) uiZ.v64 = packToF128UI64( 1, 0x3FFF, 0 );
                break;
             case softfloat_round_max:
                if ( !uiZ.v64 ) uiZ.v64 = packToF128UI64( 0, 0x3FFF, 0 );
                break;
#ifdef SOFTFLOAT_ROUND_ODD
             case softfloat_round_odd:
                uiZ.v64 |= packToF128UI64( 0, 0x3FFF, 0 );
                break;
#endif
            }
            goto uiZ;
        }
        /*--------------------------------------------------------------------
        *--------------------------------------------------------------------*/
        uiZ.v64 = uiA64;
        uiZ.v0  = 0;
        lastBitMask64 = (uint_fast64_t) 1<<(0x402F - exp);
        roundBitsMask = lastBitMask64 - 1;
        if ( roundingMode == softfloat_round_near_maxMag ) {
            uiZ.v64 += lastBitMask64>>1;
        } else if ( roundingMode == softfloat_round_near_even ) {
            uiZ.v64 += lastBitMask64>>1;
            if ( !((uiZ.v64 & roundBitsMask) | uiA0) ) {
                uiZ.v64 &= ~lastBitMask64;
            }
        } else if (
            roundingMode
                == (signF128UI64( uiZ.v64 ) ? softfloat_round_min
                        : softfloat_round_max)
        ) {
            uiZ.v64 = (uiZ.v64 | (uiA0 != 0)) + roundBitsMask;
        }
        uiZ.v64 &= ~roundBitsMask;
        lastBitMask0 = 0;
    }
    if ( (uiZ.v64 != uiA64) || (uiZ.v0 != uiA0) ) {
#ifdef SOFTFLOAT_ROUND_ODD
        if ( roundingMode == softfloat_round_odd ) {
            uiZ.v64 |= lastBitMask64;
            uiZ.v0  |= lastBitMask0;
        }
#endif
        if ( exact ) softfloat_exceptionFlags |= softfloat_flag_inexact;
    }
 uiZ:
    uZ.ui = uiZ;
    return uZ.f;
 
}

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