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Add and document ilogbl(), a long double version of ilogb().

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This commit is contained in:
Stefan Farfeleder 2004-10-11 18:13:52 +00:00
parent f1f6501da8
commit 2fd3a32ee1
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=136385
4 changed files with 65 additions and 4 deletions
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5
lib/msun/Makefile
View File

@ -85,7 +85,7 @@ COMMON_SRCS= b_exp.c b_log.c b_tgamma.c \
s_expm1.c s_expm1f.c s_fabsf.c s_fdim.c s_finite.c s_finitef.c \
s_floor.c s_floorf.c s_fmax.c s_fmaxf.c s_fmaxl.c s_fmin.c \
s_fminf.c s_fminl.c s_frexp.c s_frexpf.c s_ilogb.c s_ilogbf.c \
s_isfinite.c s_isnan.c s_isnormal.c s_ldexpf.c \
s_ilogbl.c s_isfinite.c s_isnan.c s_isnormal.c s_ldexpf.c \
s_lib_version.c s_log1p.c \
s_log1pf.c s_logb.c s_logbf.c s_matherr.c s_modff.c \
s_nearbyint.c s_nextafter.c s_nextafterf.c \
@ -167,7 +167,8 @@ MLINKS+=fmod.3 fmodf.3
MLINKS+=hypot.3 cabs.3 hypot.3 cabsf.3 hypot.3 hypotf.3
MLINKS+=ieee.3 copysign.3 ieee.3 copysignf.3 ieee.3 copysignl.3 \
ieee.3 finite.3 ieee.3 finitef.3 \
ieee.3 ilogb.3 ieee.3 ilogbf.3 ieee.3 nextafter.3 ieee.3 nextafterf.3 \
ieee.3 ilogb.3 ieee.3 ilogbf.3 ieee.3 ilogbl.3 \
ieee.3 nextafter.3 ieee.3 nextafterf.3 \
ieee.3 remainder.3 ieee.3 remainderf.3 \
ieee.3 scalbln.3 ieee.3 scalblnf.3 ieee.3 scalbn.3 ieee.3 scalbnf.3
MLINKS+=ieee_test.3 logb.3 ieee_test.3 logbf.3

8
lib/msun/man/ieee.3
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@ -43,6 +43,7 @@
.Nm finitef ,
.Nm ilogb ,
.Nm ilogbf ,
.Nm ilogbl ,
.Nm nextafter ,
.Nm nextafterf ,
.Nm remainder ,
@ -70,6 +71,8 @@
.Fn ilogb "double x"
.Ft int
.Fn ilogbf "float x"
.Ft int
.Fn ilogbl "long double x"
.Ft double
.Fn nextafter "double x" "double y"
.Ft float
@ -116,9 +119,10 @@ zero is returned
.Fa x
is \*(Na).
.Pp
.Fn ilogb
and
.Fn ilogb ,
.Fn ilogbf
and
.Fn ilogbl
return
.Fa x Ns 's exponent,
in integer format.

2
lib/msun/src/math.h
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@ -447,7 +447,9 @@ long double fminl(long double, long double) __pure2;
long double fmodl(long double, long double);
long double frexpl(long double value, int *);
long double hypotl(long double, long double);
#endif
int ilogbl(long double);
#if 0
long double ldexpl(long double, int);
long double lgammal(long double);
long long llrintl(long double);

54
lib/msun/src/s_ilogbl.c Normal file
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@ -0,0 +1,54 @@
/*
* From: @(#)s_ilogb.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.
* ====================================================
*/
#ifndef lint
static char rcsid[] = "$FreeBSD$";
#endif
#include <float.h>
#include <limits.h>
#include <math.h>
#include "fpmath.h"
int
ilogbl(long double x)
{
union IEEEl2bits u;
unsigned long m;
int b;
u.e = x;
if (u.bits.exp == 0) {
if ((u.bits.manl | u.bits.manh) == 0)
return (FP_ILOGB0);
/* denormalized */
if (u.bits.manh == 0) {
m = 1lu << (LDBL_MANL_SIZE - 1);
for (b = LDBL_MANH_SIZE; !(u.bits.manl & m); m >>= 1)
b++;
} else {
m = 1lu << (LDBL_MANH_SIZE - 1);
for (b = 0; !(u.bits.manh & m); m >>= 1)
b++;
}
#ifdef LDBL_IMPLICIT_NBIT
b++;
#endif
return (LDBL_MIN_EXP - b - 1);
} else if (u.bits.exp < (LDBL_MAX_EXP << 1) - 1)
return (u.bits.exp - LDBL_MAX_EXP + 1);
else if (u.bits.manl != 0 || u.bits.manh != 0)
return (FP_ILOGBNAN);
else
return (INT_MAX);
}