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/*
* ====================================================
* Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
*
* Developed at SunPro, a Sun Microsystems, Inc. business.
* Permission to use, copy, modify, and distribute this
* software is freely granted, provided that this notice
* is preserved.
* ====================================================
*
* From: @(#)s_floor.c 5.1 93/09/24
*/
/*
* truncl(x)
* Return x rounded toward 0 to integral value
* Method:
* Bit twiddling.
* Exception:
* Inexact flag raised if x not equal to truncl(x).
*/
#include <sys/types.h>
#include <machine/ieee.h>
#include <float.h>
#include <math.h>
#include <stdint.h>
#include "math_private.h"
#ifdef LDBL_IMPLICIT_NBIT
#define MANH_SIZE (EXT_FRACHBITS + EXT_FRACHMBITS + 1)
#else
#define MANH_SIZE (EXT_FRACHBITS + EXT_FRACHMBITS)
#endif
static const long double huge = 1.0e300;
static const float zero[] = { 0.0, -0.0 };
long double
truncl(long double x)
{
int e;
int64_t ix0, ix1;
GET_LDOUBLE_WORDS64(ix0,ix1,x);
e = ((ix0>>48)&0x7fff) - LDBL_MAX_EXP + 1;
if (e < MANH_SIZE - 1) {
if (e < 0) { /* raise inexact if x != 0 */
if (huge + x > 0.0)
return (zero[((ix0>>48)&0x8000)!=0]);
} else {
uint64_t m = ((1llu << MANH_SIZE) - 1) >> (e + 1);
if (((ix0 & m) | ix1) == 0)
return (x); /* x is integral */
if (huge + x > 0.0) { /* raise inexact flag */
ix0 &= ~m;
ix1 = 0;
}
}
} else if (e < LDBL_MANT_DIG - 1) {
uint64_t m = (uint64_t)-1 >> (64 - LDBL_MANT_DIG + e + 1);
if ((ix1 & m) == 0)
return (x); /* x is integral */
if (huge + x > 0.0) /* raise inexact flag */
ix1 &= ~m;
}
SET_LDOUBLE_WORDS64(x,ix0,ix1);
return (x);
}
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