/* @(#)s_modf.c 5.1 93/09/24 */ | |
/* | |
* ==================================================== | |
* 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 <LibConfig.h> | |
#include <sys/EfiCdefs.h> | |
#if defined(LIBM_SCCS) && !defined(lint) | |
__RCSID("$NetBSD: s_modf.c,v 1.11 2002/05/26 22:01:57 wiz Exp $"); | |
#endif | |
/* | |
* modf(double x, double *iptr) | |
* return fraction part of x, and return x's integral part in *iptr. | |
* Method: | |
* Bit twiddling. | |
* | |
* Exception: | |
* No exception. | |
*/ | |
#include "math.h" | |
#include "math_private.h" | |
static const double one = 1.0; | |
double | |
modf(double x, double *iptr) | |
{ | |
int32_t i0,i1,j0; | |
u_int32_t i; | |
EXTRACT_WORDS(i0,i1,x); | |
j0 = ((i0>>20)&0x7ff)-0x3ff; /* exponent of x */ | |
if(j0<20) { /* integer part in high x */ | |
if(j0<0) { /* |x|<1 */ | |
INSERT_WORDS(*iptr,i0&0x80000000,0); /* *iptr = +-0 */ | |
return x; | |
} else { | |
i = (0x000fffff)>>j0; | |
if(((i0&i)|i1)==0) { /* x is integral */ | |
u_int32_t high; | |
*iptr = x; | |
GET_HIGH_WORD(high,x); | |
INSERT_WORDS(x,high&0x80000000,0); /* return +-0 */ | |
return x; | |
} else { | |
INSERT_WORDS(*iptr,i0&(~i),0); | |
return x - *iptr; | |
} | |
} | |
} else if (j0>51) { /* no fraction part */ | |
u_int32_t high; | |
*iptr = x*one; | |
GET_HIGH_WORD(high,x); | |
INSERT_WORDS(x,high&0x80000000,0); /* return +-0 */ | |
return x; | |
} else { /* fraction part in low x */ | |
i = ((u_int32_t)(0xffffffff))>>(j0-20); | |
if((i1&i)==0) { /* x is integral */ | |
u_int32_t high; | |
*iptr = x; | |
GET_HIGH_WORD(high,x); | |
INSERT_WORDS(x,high&0x80000000,0); /* return +-0 */ | |
return x; | |
} else { | |
INSERT_WORDS(*iptr,i0,i1&(~i)); | |
return x - *iptr; | |
} | |
} | |
} |