glibc/sysdeps/ieee754/ldbl-128ibm/s_modfl.c
Alan Modra 765714cafc PowerPC floating point little-endian [3 of 15]
http://sourceware.org/ml/libc-alpha/2013-08/msg00083.html

Further replacement of ieee854 macros and unions.  These files also
have some optimisations for comparison against 0.0L, infinity and nan.
Since the ABI specifies that the high double of an IBM long double
pair is the value rounded to double, a high double of 0.0 means the
low double must also be 0.0.  The ABI also says that infinity and
nan are encoded in the high double, with the low double unspecified.
This means that tests for 0.0L, +/-Infinity and +/-NaN need only check
the high double.

	* sysdeps/ieee754/ldbl-128ibm/e_atan2l.c (__ieee754_atan2l): Rewrite
	all uses of ieee854 long double macros and unions.  Simplify tests
	for long doubles that are fully specified by the high double.
	* sysdeps/ieee754/ldbl-128ibm/e_gammal_r.c (__ieee754_gammal_r):
	Likewise.
	* sysdeps/ieee754/ldbl-128ibm/e_ilogbl.c (__ieee754_ilogbl): Likewise.
	Remove dead code too.
	* sysdeps/ieee754/ldbl-128ibm/e_jnl.c (__ieee754_jnl): Likewise.
	(__ieee754_ynl): Likewise.
	* sysdeps/ieee754/ldbl-128ibm/e_log10l.c (__ieee754_log10l): Likewise.
	* sysdeps/ieee754/ldbl-128ibm/e_logl.c (__ieee754_logl): Likewise.
	* sysdeps/ieee754/ldbl-128ibm/e_powl.c (__ieee754_powl): Likewise.
	Remove dead code too.
	* sysdeps/ieee754/ldbl-128ibm/k_tanl.c (__kernel_tanl): Likewise.
	* sysdeps/ieee754/ldbl-128ibm/s_expm1l.c (__expm1l): Likewise.
	* sysdeps/ieee754/ldbl-128ibm/s_frexpl.c (__frexpl): Likewise.
	* sysdeps/ieee754/ldbl-128ibm/s_isinf_nsl.c (__isinf_nsl): Likewise.
	Simplify.
	* sysdeps/ieee754/ldbl-128ibm/s_isinfl.c (___isinfl): Likewise.
	Simplify.
	* sysdeps/ieee754/ldbl-128ibm/s_log1pl.c (__log1pl): Likewise.
	* sysdeps/ieee754/ldbl-128ibm/s_modfl.c (__modfl): Likewise.
	* sysdeps/ieee754/ldbl-128ibm/s_nextafterl.c (__nextafterl): Likewise.
	Comment on variable precision.
	* sysdeps/ieee754/ldbl-128ibm/s_nexttoward.c (__nexttoward): Likewise.
	* sysdeps/ieee754/ldbl-128ibm/s_nexttowardf.c (__nexttowardf):
	Likewise.
	* sysdeps/ieee754/ldbl-128ibm/s_remquol.c (__remquol): Likewise.
	* sysdeps/ieee754/ldbl-128ibm/s_scalblnl.c (__scalblnl): Likewise.
	* sysdeps/ieee754/ldbl-128ibm/s_scalbnl.c (__scalbnl): Likewise.
	* sysdeps/ieee754/ldbl-128ibm/s_tanhl.c (__tanhl): Likewise.
	* sysdeps/powerpc/fpu/libm-test-ulps: Adjust tan_towardzero ulps.
2013-10-04 10:32:36 +09:30

97 lines
2.4 KiB
C

/* s_modfl.c -- long double version of s_modf.c.
* Conversion to IEEE quad long double by Jakub Jelinek, jj@ultra.linux.cz.
*/
/*
* ====================================================
* 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.
* ====================================================
*/
#if defined(LIBM_SCCS) && !defined(lint)
static char rcsid[] = "$NetBSD: $";
#endif
/*
* modfl(long double x, long 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>
#include <math_ldbl_opt.h>
static const long double one = 1.0;
long double __modfl(long double x, long double *iptr)
{
int64_t i0,i1,j0;
u_int64_t i;
double xhi, xlo;
ldbl_unpack (x, &xhi, &xlo);
EXTRACT_WORDS64 (i0, xhi);
EXTRACT_WORDS64 (i1, xlo);
i1 &= 0x000fffffffffffffLL;
j0 = ((i0>>52)&0x7ff)-0x3ff; /* exponent of x */
if(j0<52) { /* integer part in high x */
if(j0<0) { /* |x|<1 */
/* *iptr = +-0 */
INSERT_WORDS64 (xhi, i0&0x8000000000000000ULL);
*iptr = xhi;
return x;
} else {
i = (0x000fffffffffffffLL)>>j0;
if(((i0&i)|(i1&0x7fffffffffffffffLL))==0) { /* x is integral */
*iptr = x;
/* return +-0 */
INSERT_WORDS64 (xhi, i0&0x8000000000000000ULL);
x = xhi;
return x;
} else {
INSERT_WORDS64 (xhi, i0&(~i));
*iptr = xhi;
return x - *iptr;
}
}
} else if (j0>103) { /* no fraction part */
*iptr = x*one;
/* We must handle NaNs separately. */
if ((i0 & 0x7fffffffffffffffLL) > 0x7ff0000000000000LL)
return x*one;
/* return +-0 */
INSERT_WORDS64 (xhi, i0&0x8000000000000000ULL);
x = xhi;
return x;
} else { /* fraction part in low x */
i = -1ULL>>(j0-52);
if((i1&i)==0) { /* x is integral */
*iptr = x;
/* return +-0 */
INSERT_WORDS64 (xhi, i0&0x8000000000000000ULL);
x = xhi;
return x;
} else {
INSERT_WORDS64 (xhi, i0);
INSERT_WORDS64 (xlo, i1&(~i));
*iptr = ldbl_pack (xhi, xlo);
return x - *iptr;
}
}
}
#ifdef IS_IN_libm
long_double_symbol (libm, __modfl, modfl);
#else
long_double_symbol (libc, __modfl, modfl);
#endif