glibc/sysdeps/libm-ieee754/s_log2f.c
Ulrich Drepper 22d57dd369 Update.
1997-04-02 16:28  Ulrich Drepper  <drepper@cygnus.com>

	* grp/fgetgrent.c: Don't use fixed buffer length.  Allow dynamic
	adjustment if the underlying function say it is too small.
	* pwd/fgetpwent.c: Likewise.
	* shadow/fgetspent.c: Likewise.
	* shadow/sgetspent.c: Likewise.

	* grp/fgetgrent_r.c (__fgetgrent_r): If `parse_result' returns -1
	this means there was not enough room for the gr_mem array.

	* nss/nss_files/files-XXX.c: Leave loop and return error if
	`parse_result' returns -1.

	* nss/nss_files/files-parse.c (parse_line): Return -1 if parsing
	of trailing list fails because of low memory.
	(parse_list): Rewrite.  The logic was completly incorrect since
	the checks for overflowing the array were not executed when
	needed.

	* shadow/sgetspent_r.c: Only a return value > 0 from parse_line
	signals success.

	* nss/getXXbyYY.c: Make sure NULL is returned if we ran out of memory.
	* nss/getXXent.c: Likewise.

	* stdlib/strtod.c (SET_MANTISSA): Make sure that at least one bit
	is set in mantissa.
	* stdlib/strtof.c: Likewise.
	* stdlib/strtold.c: Likewise.
	* wcsmbs/wcstof.c: Likewise.
	* wcsmbs/wcstold.c: Likewise.

	* sysdeps/libm-ieee754/s_nan.c: Use strtod is parameter is not empty
	string.
	* sysdeps/libm-ieee754/s_nanf.c: Likewise.
	* sysdeps/libm-ieee754/s_nanld.c: Likewise.

1997-04-02 13:56  Ulrich Drepper  <drepper@cygnus.com>

	* manual/errno.texi: Add description of strerror_r.

1997-04-01 19:07  H.J. Lu (hjl@gnu.ai.mit.edu)

	* manual/errno.texi: Add ENOMEDIUM and EMEDIUMTYPE.

1997-04-02 13:55  Ulrich Drepper  <drepper@cygnus.com>

	* sysdeps/gnu/errlist.awk: The Texinfo file is named errno.texi.

1997-03-30 10:59  Andreas Schwab  <schwab@issan.informatik.uni-dortmund.de>

	* sysdeps/m68k/fpu/s_cexp.c: New file.
	* sysdeps/m68k/fpu/s_cexpf.c: New file.
	* sysdeps/m68k/fpu/s_cexpl.c: New file.
	* sysdeps/m68k/fpu/s_nearbyint.c: New file.
	* sysdeps/m68k/fpu/s_nearbyintf.c: New file.
	* sysdeps/m68k/fpu/s_nearbyintl.c: New file.
	* sysdeps/m68k/fpu/s_trunc.c: New file.
	* sysdeps/m68k/fpu/s_truncf.c: New file.
	* sysdeps/m68k/fpu/s_truncl.c: New file.

	* sysdeps/m68k/fpu/s_modf.c: Rewritten.
	* sysdeps/m68k/fpu/s_modff.c: Adapted.
	* sysdeps/m68k/fpu/s_modfl.c: Likewise.

	* sysdeps/m68k/fpu/e_atan2.c: Use __signbit inline.
	* sysdeps/m68k/fpu/e_pow.c: Likewise.  Write 0.0/0.0 for NaN.  Fix
	typo in test for `y = 0.5'.

	* sysdeps/m68k/fpu/__math.h: Define __trunc, __signbit,
	__nearbyint.  Remove __modf.

	* sysdeps/m68k/Makefile (CFLAGS-s_copysignl.c) [$(subdir)=math]:
	Define for gcc bug workaround.

	* math/libm-test.c (log2_test): Add epsilon for long double to
	"log2 (e)" and "log2 (16)".
	(modf_test): Fix test name.
	(sqrt_test): Add missing FUNC.

1997-03-29 16:24  Andreas Schwab  <schwab@issan.informatik.uni-dortmund.de>

	* sunrpc/Makefile (CFLAGS-xrquota.c): Fix typo in variable name.

1997-03-28 20:56  Andreas Schwab  <schwab@issan.informatik.uni-dortmund.de>

	* stdlib/stdlib.h: Declare __clearenv.

1997-03-28 18:03  Andreas Schwab  <schwab@issan.informatik.uni-dortmund.de>

	* sysdeps/libm-ieee754/s_asinhl.c: Fix Ulrich Dreppers mangling of
	the last change.

1997-03-28 17:55  Andreas Schwab  <schwab@issan.informatik.uni-dortmund.de>

	* configure.in: Call AC_CANONICAL_BUILD before referencing
	$build.  Fix test for BUILD_CC.

1997-04-02 01:29  Philip Blundell  <pjb27@cam.ac.uk>

	* sysdeps/libm-ieee754/s_log2f.c (__log2f): Fix typo.

1997-03-31 18:53  Philip Blundell  <pjb27@cam.ac.uk>

	* sysdeps/unix/sysv/linux/net/route.h: Add new IPv6 definitions.

1997-04-01 14:08  Ulrich Drepper  <drepper@cygnus.com>

	* sysdeps/i386/memset.c: Fix typo.
	* sysdeps/stub/fchmod.c: Fix typo.
	* sysdeps/stub/fchdir.c: Fix typo.
	Reported by Fila Kolodny <fila@ibi.com>.
1997-04-02 14:47:34 +00:00

91 lines
2.2 KiB
C

/* e_logf.c -- float version of e_log.c.
* Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
* adapted for log2 by Ulrich Drepper <drepper@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 "math.h"
#include "math_private.h"
#ifdef __STDC__
static const float
#else
static float
#endif
two25 = 3.355443200e+07, /* 0x4c000000 */
Lg1 = 6.6666668653e-01, /* 3F2AAAAB */
Lg2 = 4.0000000596e-01, /* 3ECCCCCD */
Lg3 = 2.8571429849e-01, /* 3E924925 */
Lg4 = 2.2222198546e-01, /* 3E638E29 */
Lg5 = 1.8183572590e-01, /* 3E3A3325 */
Lg6 = 1.5313838422e-01, /* 3E1CD04F */
Lg7 = 1.4798198640e-01; /* 3E178897 */
#ifdef __STDC__
static const float zero = 0.0;
#else
static float zero = 0.0;
#endif
#ifdef __STDC__
float __log2f(float x)
#else
float __log2f(x)
float x;
#endif
{
float hfsq,f,s,z,R,w,t1,t2,dk;
int32_t k,ix,i,j;
GET_FLOAT_WORD(ix,x);
k=0;
if (ix < 0x00800000) { /* x < 2**-126 */
if ((ix&0x7fffffff)==0)
return -two25/zero; /* log(+-0)=-inf */
if (ix<0) return (x-x)/zero; /* log(-#) = NaN */
k -= 25; x *= two25; /* subnormal number, scale up x */
GET_FLOAT_WORD(ix,x);
}
if (ix >= 0x7f800000) return x+x;
k += (ix>>23)-127;
ix &= 0x007fffff;
i = (ix+(0x95f64<<3))&0x800000;
SET_FLOAT_WORD(x,ix|(i^0x3f800000)); /* normalize x or x/2 */
k += (i>>23);
dk = (float)k;
f = x-(float)1.0;
if((0x007fffff&(15+ix))<16) { /* |f| < 2**-20 */
if(f==zero) return dk;
R = f*f*((float)0.5-(float)0.33333333333333333*f);
return dk-(R-f);
}
s = f/((float)2.0+f);
z = s*s;
i = ix-(0x6147a<<3);
w = z*z;
j = (0x6b851<<3)-ix;
t1= w*(Lg2+w*(Lg4+w*Lg6));
t2= z*(Lg1+w*(Lg3+w*(Lg5+w*Lg7)));
i |= j;
R = t2+t1;
if(i>0) {
hfsq=(float)0.5*f*f;
return dk-((hfsq-(s*(hfsq+R)))-f);
} else {
return dk-((s*(f-R))-f);
}
}
weak_alias (__log2f, log2f)