new modff.c code, fix nan handling in modfl

This commit is contained in:
nsz
2012-03-19 23:27:45 +01:00
parent 2786c7d216
commit 75483499da
2 changed files with 26 additions and 44 deletions

View File

@ -1,51 +1,33 @@
/* origin: FreeBSD /usr/src/lib/msun/src/s_modff.c */
/*
* Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
*/
/*
* ====================================================
* 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.
* ====================================================
*/
#include "libm.h"
static const float one = 1.0;
float modff(float x, float *iptr)
{
int32_t i0,j0;
uint32_t i;
uint32_t u, mask;
int e;
GET_FLOAT_WORD(i0, x);
j0 = ((i0>>23) & 0xff) - 0x7f; /* exponent of x */
if (j0 < 23) { /* integer part in x */
if (j0 < 0) { /* |x| < 1 */
SET_FLOAT_WORD(*iptr, i0 & 0x80000000); /* *iptr = +-0 */
return x;
}
i = 0x007fffff >> j0;
if ((i0&i) == 0) { /* x is integral */
uint32_t ix;
GET_FLOAT_WORD(u, x);
e = (int)(u>>23 & 0xff) - 0x7f;
/* no fractional part */
if (e >= 23) {
*iptr = x;
GET_FLOAT_WORD(ix, x);
SET_FLOAT_WORD(x, ix & 0x80000000); /* return +-0 */
if (e == 0x80 && u<<9 != 0) /* nan */
return x;
SET_FLOAT_WORD(x, u & 0x80000000);
return x;
}
SET_FLOAT_WORD(*iptr, i0&~i);
/* no integral part */
if (e < 0) {
SET_FLOAT_WORD(*iptr, u & 0x80000000);
return x;
}
mask = 0x007fffff>>e;
if ((u & mask) == 0) {
*iptr = x;
SET_FLOAT_WORD(x, u & 0x80000000);
return x;
}
SET_FLOAT_WORD(*iptr, u & ~mask);
return x - *iptr;
} else { /* no fraction part */
uint32_t ix;
*iptr = x*one;
if (x != x) /* NaN */
return x;
GET_FLOAT_WORD(ix, x);
SET_FLOAT_WORD(x, ix & 0x80000000); /* return +-0 */
return x;
}
}

View File

@ -54,7 +54,7 @@ long double modfl(long double x, long double *iptr)
/* The number of fraction bits in manh, not counting the integer bit */
#define HIBITS (LDBL_MANT_DIG - LDBL_MANL_SIZE)
static const long double zero[] = { 0.0L, -0.0L };
static const long double zero[] = { 0.0, -0.0 };
long double modfl(long double x, long double *iptr)
{
@ -81,7 +81,7 @@ long double modfl(long double x, long double *iptr)
return x - ux.e;
} else if (e >= LDBL_MANT_DIG - 1) { /* x has no fraction part. */
*iptr = x;
if (x != x) /* Handle NaNs. */
if (e == LDBL_MAX_EXP && (ux.bits.manh|ux.bits.manl)) /* nan */
return x;
return zero[ux.bits.sign];
} else { /* Fraction part is in manl. */