f128M_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
void	f128M_roundToInt (const float128_t *aPtr, uint_fast8_t roundingMode, bool exact, float128_t *zPtr)

Function Documentation

f128M_roundToInt()

void f128M_roundToInt	(	const float128_t *	aPtr,
		uint_fast8_t	roundingMode,
		bool	exact,
		float128_t *	zPtr )

Definition at line 62 of file f128M_roundToInt.c.

{
    const uint32_t *aWPtr;
    uint32_t *zWPtr;
    uint32_t ui96;
    int32_t exp;
    uint32_t sigExtra;
    bool sign;
    uint_fast8_t bitPos;
    bool roundNear;
    unsigned int index, lastIndex;
    bool extra;
    uint32_t wordA, bit, wordZ;
    uint_fast8_t carry;
    uint32_t extrasMask;
 
    /*------------------------------------------------------------------------
    *------------------------------------------------------------------------*/
    aWPtr = (const uint32_t *) aPtr;
    zWPtr = (uint32_t *) zPtr;
    /*------------------------------------------------------------------------
    *------------------------------------------------------------------------*/
    ui96 = aWPtr[indexWordHi( 4 )];
    exp = expF128UI96( ui96 );
    /*------------------------------------------------------------------------
    *------------------------------------------------------------------------*/
    if ( exp < 0x3FFF ) {
        zWPtr[indexWord( 4, 2 )] = 0;
        zWPtr[indexWord( 4, 1 )] = 0;
        zWPtr[indexWord( 4, 0 )] = 0;
        sigExtra = aWPtr[indexWord( 4, 2 )];
        if ( !sigExtra ) {
            sigExtra = aWPtr[indexWord( 4, 1 )] | aWPtr[indexWord( 4, 0 )];
        }
        if ( !sigExtra && !(ui96 & 0x7FFFFFFF) ) goto ui96;
        if ( exact ) softfloat_exceptionFlags |= softfloat_flag_inexact;
        sign = signF128UI96( ui96 );
        switch ( roundingMode ) {
         case softfloat_round_near_even:
            if ( !fracF128UI96( ui96 ) && !sigExtra ) break;
         case softfloat_round_near_maxMag:
            if ( exp == 0x3FFE ) goto mag1;
            break;
         case softfloat_round_min:
            if ( sign ) goto mag1;
            break;
         case softfloat_round_max:
            if ( !sign ) goto mag1;
            break;
#ifdef SOFTFLOAT_ROUND_ODD
         case softfloat_round_odd:
            goto mag1;
#endif
        }
        ui96 = packToF128UI96( sign, 0, 0 );
        goto ui96;
     mag1:
        ui96 = packToF128UI96( sign, 0x3FFF, 0 );
        goto ui96;
    }
    /*------------------------------------------------------------------------
    *------------------------------------------------------------------------*/
    if ( 0x406F <= exp ) {
        if (
            (exp == 0x7FFF)
                && (fracF128UI96( ui96 )
                        || (aWPtr[indexWord( 4, 2 )] | aWPtr[indexWord( 4, 1 )]
                                | aWPtr[indexWord( 4, 0 )]))
        ) {
            softfloat_propagateNaNF128M( aWPtr, 0, zWPtr );
            return;
        }
        zWPtr[indexWord( 4, 2 )] = aWPtr[indexWord( 4, 2 )];
        zWPtr[indexWord( 4, 1 )] = aWPtr[indexWord( 4, 1 )];
        zWPtr[indexWord( 4, 0 )] = aWPtr[indexWord( 4, 0 )];
        goto ui96;
    }
    /*------------------------------------------------------------------------
    *------------------------------------------------------------------------*/
    bitPos = 0x406F - exp;
    roundNear =
           (roundingMode == softfloat_round_near_maxMag)
        || (roundingMode == softfloat_round_near_even);
    bitPos -= roundNear;
    index = indexWordLo( 4 );
    lastIndex = indexWordHi( 4 );
    extra = 0;
    for (;;) {
        wordA = aWPtr[index];
        if ( bitPos < 32 ) break;
        if ( wordA ) extra = 1;
        zWPtr[index] = 0;
        index += wordIncr;
        bitPos -= 32;
    }
    bit = (uint32_t) 1<<bitPos;
    if ( roundNear ) {
        wordZ = wordA + bit;
        carry = (wordZ < wordA);
        bit <<= 1;
        extrasMask = bit - 1;
        if ( exact && (extra || (wordA & extrasMask)) ) {
            softfloat_exceptionFlags |= softfloat_flag_inexact;
        }
        if (
            (roundingMode == softfloat_round_near_even)
                && !extra && !(wordZ & extrasMask)
        ) {
            if ( !bit ) {
                zWPtr[index] = wordZ;
                index += wordIncr;
                wordZ = aWPtr[index] + carry;
                carry &= !wordZ;
                zWPtr[index] = wordZ & ~1;
                goto propagateCarry;
            }
            wordZ &= ~bit;
        }
    } else {
        wordZ = wordA;
        carry = 0;
        extrasMask = bit - 1;
        if ( extra || (wordA & extrasMask) ) {
            if ( exact ) softfloat_exceptionFlags |= softfloat_flag_inexact;
            if (
                roundingMode
                    == (signF128UI96( ui96 ) ? softfloat_round_min
                            : softfloat_round_max)
            ) {
                wordZ += bit;
                carry = (wordZ < wordA);
#ifdef SOFTFLOAT_ROUND_ODD
            } else if ( roundingMode == softfloat_round_odd ) {
                wordZ |= bit;
#endif
            }
        }
    }
    wordZ &= ~extrasMask;
    zWPtr[index] = wordZ;
 propagateCarry:
    while ( index != lastIndex ) {
        index += wordIncr;
        wordZ = aWPtr[index] + carry;
        zWPtr[index] = wordZ;
        carry &= !wordZ;
    }
    return;
    /*------------------------------------------------------------------------
    *------------------------------------------------------------------------*/
 ui96:
    zWPtr[indexWordHi( 4 )] = ui96;
 
}

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