s_roundPackToExtF80.c File Reference

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

Include dependency graph for s_roundPackToExtF80.c:

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Functions
extFloat80_t	softfloat_roundPackToExtF80 (bool sign, int_fast32_t exp, uint_fast64_t sig, uint_fast64_t sigExtra, uint_fast8_t roundingPrecision)

Function Documentation

softfloat_roundPackToExtF80()

extFloat80_t softfloat_roundPackToExtF80	(	bool	sign,
		int_fast32_t	exp,
		uint_fast64_t	sig,
		uint_fast64_t	sigExtra,
		uint_fast8_t	roundingPrecision )

Definition at line 44 of file s_roundPackToExtF80.c.

{
    uint_fast8_t roundingMode;
    bool roundNearEven;
    uint_fast64_t roundIncrement, roundMask, roundBits;
    bool isTiny, doIncrement;
    struct uint64_extra sig64Extra;
    union { struct extFloat80M s; extFloat80_t f; } uZ;
 
    /*------------------------------------------------------------------------
    *------------------------------------------------------------------------*/
    roundingMode = softfloat_roundingMode;
    roundNearEven = (roundingMode == softfloat_round_near_even);
    if ( roundingPrecision == 80 ) goto precision80;
    if ( roundingPrecision == 64 ) {
        roundIncrement = UINT64_C( 0x0000000000000400 );
        roundMask = UINT64_C( 0x00000000000007FF );
    } else if ( roundingPrecision == 32 ) {
        roundIncrement = UINT64_C( 0x0000008000000000 );
        roundMask = UINT64_C( 0x000000FFFFFFFFFF );
    } else {
        goto precision80;
    }
    sig |= (sigExtra != 0);
    if ( ! roundNearEven && (roundingMode != softfloat_round_near_maxMag) ) {
        roundIncrement =
            (roundingMode
                 == (sign ? softfloat_round_min : softfloat_round_max))
                ? roundMask
                : 0;
    }
    roundBits = sig & roundMask;
    /*------------------------------------------------------------------------
    *------------------------------------------------------------------------*/
    if ( 0x7FFD <= (uint32_t) (exp - 1) ) {
        if ( exp <= 0 ) {
            /*----------------------------------------------------------------
            *----------------------------------------------------------------*/
            isTiny =
                   (softfloat_detectTininess
                        == softfloat_tininess_beforeRounding)
                || (exp < 0)
                || (sig <= (uint64_t) (sig + roundIncrement));
            sig = softfloat_shiftRightJam64( sig, 1 - exp );
            roundBits = sig & roundMask;
            if ( roundBits ) {
                if ( isTiny ) softfloat_raiseFlags( softfloat_flag_underflow );
                softfloat_exceptionFlags |= softfloat_flag_inexact;
#ifdef SOFTFLOAT_ROUND_ODD
                if ( roundingMode == softfloat_round_odd ) {
                    sig |= roundMask + 1;
                }
#endif
            }
            sig += roundIncrement;
            exp = ((sig & UINT64_C( 0x8000000000000000 )) != 0);
            roundIncrement = roundMask + 1;
            if ( roundNearEven && (roundBits<<1 == roundIncrement) ) {
                roundMask |= roundIncrement;
            }
            sig &= ~roundMask;
            goto packReturn;
        }
        if (
               (0x7FFE < exp)
            || ((exp == 0x7FFE) && ((uint64_t) (sig + roundIncrement) < sig))
        ) {
            goto overflow;
        }
    }
    /*------------------------------------------------------------------------
    *------------------------------------------------------------------------*/
    if ( roundBits ) {
        softfloat_exceptionFlags |= softfloat_flag_inexact;
#ifdef SOFTFLOAT_ROUND_ODD
        if ( roundingMode == softfloat_round_odd ) {
            sig = (sig & ~roundMask) | (roundMask + 1);
            goto packReturn;
        }
#endif
    }
    sig = (uint64_t) (sig + roundIncrement);
    if ( sig < roundIncrement ) {
        ++exp;
        sig = UINT64_C( 0x8000000000000000 );
    }
    roundIncrement = roundMask + 1;
    if ( roundNearEven && (roundBits<<1 == roundIncrement) ) {
        roundMask |= roundIncrement;
    }
    sig &= ~roundMask;
    goto packReturn;
    /*------------------------------------------------------------------------
    *------------------------------------------------------------------------*/
 precision80:
    doIncrement = (UINT64_C( 0x8000000000000000 ) <= sigExtra);
    if ( ! roundNearEven && (roundingMode != softfloat_round_near_maxMag) ) {
        doIncrement =
            (roundingMode
                 == (sign ? softfloat_round_min : softfloat_round_max))
                && sigExtra;
    }
    /*------------------------------------------------------------------------
    *------------------------------------------------------------------------*/
    if ( 0x7FFD <= (uint32_t) (exp - 1) ) {
        if ( exp <= 0 ) {
            /*----------------------------------------------------------------
            *----------------------------------------------------------------*/
            isTiny =
                   (softfloat_detectTininess
                        == softfloat_tininess_beforeRounding)
                || (exp < 0)
                || ! doIncrement
                || (sig < UINT64_C( 0xFFFFFFFFFFFFFFFF ));
            sig64Extra =
                softfloat_shiftRightJam64Extra( sig, sigExtra, 1 - exp );
            exp = 0;
            sig = sig64Extra.v;
            sigExtra = sig64Extra.extra;
            if ( sigExtra ) {
                if ( isTiny ) softfloat_raiseFlags( softfloat_flag_underflow );
                softfloat_exceptionFlags |= softfloat_flag_inexact;
#ifdef SOFTFLOAT_ROUND_ODD
                if ( roundingMode == softfloat_round_odd ) {
                    sig |= 1;
                    goto packReturn;
                }
#endif
            }
            doIncrement = (UINT64_C( 0x8000000000000000 ) <= sigExtra);
            if (
                ! roundNearEven
                    && (roundingMode != softfloat_round_near_maxMag)
            ) {
                doIncrement =
                    (roundingMode
                         == (sign ? softfloat_round_min : softfloat_round_max))
                        && sigExtra;
            }
            if ( doIncrement ) {
                ++sig;
                sig &=
                    ~(uint_fast64_t)
                         (! (sigExtra & UINT64_C( 0x7FFFFFFFFFFFFFFF ))
                              & roundNearEven);
                exp = ((sig & UINT64_C( 0x8000000000000000 )) != 0);
            }
            goto packReturn;
        }
        if (
               (0x7FFE < exp)
            || ((exp == 0x7FFE) && (sig == UINT64_C( 0xFFFFFFFFFFFFFFFF ))
                    && doIncrement)
        ) {
            /*----------------------------------------------------------------
            *----------------------------------------------------------------*/
            roundMask = 0;
 overflow:
            softfloat_raiseFlags(
                softfloat_flag_overflow | softfloat_flag_inexact );
            if (
                   roundNearEven
                || (roundingMode == softfloat_round_near_maxMag)
                || (roundingMode
                        == (sign ? softfloat_round_min : softfloat_round_max))
            ) {
                exp = 0x7FFF;
                sig = UINT64_C( 0x8000000000000000 );
            } else {
                exp = 0x7FFE;
                sig = ~roundMask;
            }
            goto packReturn;
        }
    }
    /*------------------------------------------------------------------------
    *------------------------------------------------------------------------*/
    if ( sigExtra ) {
        softfloat_exceptionFlags |= softfloat_flag_inexact;
#ifdef SOFTFLOAT_ROUND_ODD
        if ( roundingMode == softfloat_round_odd ) {
            sig |= 1;
            goto packReturn;
        }
#endif
    }
    if ( doIncrement ) {
        ++sig;
        if ( ! sig ) {
            ++exp;
            sig = UINT64_C( 0x8000000000000000 );
        } else {
            sig &=
                ~(uint_fast64_t)
                     (! (sigExtra & UINT64_C( 0x7FFFFFFFFFFFFFFF ))
                          & roundNearEven);
        }
    }
    /*------------------------------------------------------------------------
    *------------------------------------------------------------------------*/
 packReturn:
    uZ.s.signExp = packToExtF80UI64( sign, exp );
    uZ.s.signif = sig;
    return uZ.f;
 
}

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