mirror of
https://sourceware.org/git/glibc.git
synced 2024-11-21 20:40:05 +00:00
Update.
2001-11-10 Andreas Jaeger <aj@suse.de> * sysdeps/ieee754/ldbl-128/e_log2l.c: New file. * sysdeps/ieee754/ldbl-128/e_log10l.c: Likewise. Contributed by Stephen L Moshier <moshier@mediaone.net>.
This commit is contained in:
Andreas Jaeger
parent
4a568eb978
commit
76321a2576
@ -1,3 +1,9 @@
|
||||
2001-11-10 Andreas Jaeger <aj@suse.de>
|
||||
|
||||
* sysdeps/ieee754/ldbl-128/e_log2l.c: New file.
|
||||
* sysdeps/ieee754/ldbl-128/e_log10l.c: Likewise.
|
||||
Contributed by Stephen L Moshier <moshier@mediaone.net>.
|
||||
|
||||
2001-11-09 Ulrich Drepper <drepper@redhat.com>
|
||||
|
||||
* elf/dl-minimal.c (realloc): Handle NULL for first parameter
|
||||
|
||||
4
NEWS
4
NEWS
@ -8,8 +8,8 @@ Please send GNU C library bug reports using the `glibcbug' script to
|
||||
|
||||
Version 2.2.5
|
||||
|
||||
* Stephen Moshier implemented powl and cbrtl for the 128-bit
|
||||
long double format.
|
||||
* Stephen Moshier implemented log2, log10, powl and cbrtl for the
|
||||
128-bit long double format.
|
||||
|
||||
* Masahide Washizawa contributed iconv modules for IBM1132, IBM1133, IBM1160,
|
||||
IBM1161, and IBM1162 charsets.
|
||||
|
||||
244
sysdeps/ieee754/ldbl-128/e_log10l.c
Normal file
244
sysdeps/ieee754/ldbl-128/e_log10l.c
Normal file
@ -0,0 +1,244 @@
|
||||
/* log10l.c
|
||||
*
|
||||
* Common logarithm, 128-bit long double precision
|
||||
*
|
||||
*
|
||||
*
|
||||
* SYNOPSIS:
|
||||
*
|
||||
* long double x, y, log10l();
|
||||
*
|
||||
* y = log10l( x );
|
||||
*
|
||||
*
|
||||
*
|
||||
* DESCRIPTION:
|
||||
*
|
||||
* Returns the base 10 logarithm of x.
|
||||
*
|
||||
* The argument is separated into its exponent and fractional
|
||||
* parts. If the exponent is between -1 and +1, the logarithm
|
||||
* of the fraction is approximated by
|
||||
*
|
||||
* log(1+x) = x - 0.5 x^2 + x^3 P(x)/Q(x).
|
||||
*
|
||||
* Otherwise, setting z = 2(x-1)/x+1),
|
||||
*
|
||||
* log(x) = z + z^3 P(z)/Q(z).
|
||||
*
|
||||
*
|
||||
*
|
||||
* ACCURACY:
|
||||
*
|
||||
* Relative error:
|
||||
* arithmetic domain # trials peak rms
|
||||
* IEEE 0.5, 2.0 30000 2.3e-34 4.9e-35
|
||||
* IEEE exp(+-10000) 30000 1.0e-34 4.1e-35
|
||||
*
|
||||
* In the tests over the interval exp(+-10000), the logarithms
|
||||
* of the random arguments were uniformly distributed over
|
||||
* [-10000, +10000].
|
||||
*
|
||||
*/
|
||||
|
||||
/*
|
||||
Cephes Math Library Release 2.2: January, 1991
|
||||
Copyright 1984, 1991 by Stephen L. Moshier
|
||||
Adapted for glibc November, 2001
|
||||
*/
|
||||
|
||||
#include "math.h"
|
||||
#include "math_private.h"
|
||||
|
||||
/* Coefficients for ln(1+x) = x - x**2/2 + x**3 P(x)/Q(x)
|
||||
* 1/sqrt(2) <= x < sqrt(2)
|
||||
* Theoretical peak relative error = 5.3e-37,
|
||||
* relative peak error spread = 2.3e-14
|
||||
*/
|
||||
static const long double P[13] =
|
||||
{
|
||||
1.313572404063446165910279910527789794488E4L,
|
||||
7.771154681358524243729929227226708890930E4L,
|
||||
2.014652742082537582487669938141683759923E5L,
|
||||
3.007007295140399532324943111654767187848E5L,
|
||||
2.854829159639697837788887080758954924001E5L,
|
||||
1.797628303815655343403735250238293741397E5L,
|
||||
7.594356839258970405033155585486712125861E4L,
|
||||
2.128857716871515081352991964243375186031E4L,
|
||||
3.824952356185897735160588078446136783779E3L,
|
||||
4.114517881637811823002128927449878962058E2L,
|
||||
2.321125933898420063925789532045674660756E1L,
|
||||
4.998469661968096229986658302195402690910E-1L,
|
||||
1.538612243596254322971797716843006400388E-6L
|
||||
};
|
||||
static const long double Q[12] =
|
||||
{
|
||||
3.940717212190338497730839731583397586124E4L,
|
||||
2.626900195321832660448791748036714883242E5L,
|
||||
7.777690340007566932935753241556479363645E5L,
|
||||
1.347518538384329112529391120390701166528E6L,
|
||||
1.514882452993549494932585972882995548426E6L,
|
||||
1.158019977462989115839826904108208787040E6L,
|
||||
6.132189329546557743179177159925690841200E5L,
|
||||
2.248234257620569139969141618556349415120E5L,
|
||||
5.605842085972455027590989944010492125825E4L,
|
||||
9.147150349299596453976674231612674085381E3L,
|
||||
9.104928120962988414618126155557301584078E2L,
|
||||
4.839208193348159620282142911143429644326E1L
|
||||
/* 1.000000000000000000000000000000000000000E0L, */
|
||||
};
|
||||
|
||||
/* Coefficients for log(x) = z + z^3 P(z^2)/Q(z^2),
|
||||
* where z = 2(x-1)/(x+1)
|
||||
* 1/sqrt(2) <= x < sqrt(2)
|
||||
* Theoretical peak relative error = 1.1e-35,
|
||||
* relative peak error spread 1.1e-9
|
||||
*/
|
||||
static const long double R[6] =
|
||||
{
|
||||
1.418134209872192732479751274970992665513E5L,
|
||||
-8.977257995689735303686582344659576526998E4L,
|
||||
2.048819892795278657810231591630928516206E4L,
|
||||
-2.024301798136027039250415126250455056397E3L,
|
||||
8.057002716646055371965756206836056074715E1L,
|
||||
-8.828896441624934385266096344596648080902E-1L
|
||||
};
|
||||
static const long double S[6] =
|
||||
{
|
||||
1.701761051846631278975701529965589676574E6L,
|
||||
-1.332535117259762928288745111081235577029E6L,
|
||||
4.001557694070773974936904547424676279307E5L,
|
||||
-5.748542087379434595104154610899551484314E4L,
|
||||
3.998526750980007367835804959888064681098E3L,
|
||||
-1.186359407982897997337150403816839480438E2L
|
||||
/* 1.000000000000000000000000000000000000000E0L, */
|
||||
};
|
||||
|
||||
static const long double
|
||||
/* log10(2) */
|
||||
L102A = 0.3125L,
|
||||
L102B -1.14700043360188047862611052755069732318101185E-2L,
|
||||
/* log10(e) */
|
||||
L10EA = 0.5L,
|
||||
L10EB = -6.570551809674817234887108108339491770560299E-2L,
|
||||
/* sqrt(2)/2 */
|
||||
SQRTH = 7.071067811865475244008443621048490392848359E-1L;
|
||||
|
||||
|
||||
|
||||
/* Evaluate P[n] x^n + P[n-1] x^(n-1) + ... + P[0] */
|
||||
|
||||
static long double
|
||||
neval (long double x, const long double *p, int n)
|
||||
{
|
||||
long double y;
|
||||
|
||||
p += n;
|
||||
y = *p--;
|
||||
do
|
||||
{
|
||||
y = y * x + *p--;
|
||||
}
|
||||
while (--n > 0);
|
||||
return y;
|
||||
}
|
||||
|
||||
|
||||
/* Evaluate x^n+1 + P[n] x^(n) + P[n-1] x^(n-1) + ... + P[0] */
|
||||
|
||||
static long double
|
||||
deval (long double x, const long double *p, int n)
|
||||
{
|
||||
long double y;
|
||||
|
||||
p += n;
|
||||
y = x + *p--;
|
||||
do
|
||||
{
|
||||
y = y * x + *p--;
|
||||
}
|
||||
while (--n > 0);
|
||||
return y;
|
||||
}
|
||||
|
||||
|
||||
|
||||
long double
|
||||
__ieee754_log10l (x)
|
||||
long double x;
|
||||
{
|
||||
long double z;
|
||||
long double y;
|
||||
int e;
|
||||
|
||||
/* Test for domain */
|
||||
if (x <= 0.0L)
|
||||
{
|
||||
if (x == 0.0L)
|
||||
return (-1.0L / (x - x));
|
||||
else
|
||||
return (x - x) / (x - x);
|
||||
}
|
||||
if (!__finitel (x))
|
||||
return (x + x);
|
||||
|
||||
/* separate mantissa from exponent */
|
||||
|
||||
/* Note, frexp is used so that denormal numbers
|
||||
* will be handled properly.
|
||||
*/
|
||||
x = __frexpl (x, &e);
|
||||
|
||||
|
||||
/* logarithm using log(x) = z + z**3 P(z)/Q(z),
|
||||
* where z = 2(x-1)/x+1)
|
||||
*/
|
||||
if ((e > 2) || (e < -2))
|
||||
{
|
||||
if (x < SQRTH)
|
||||
{ /* 2( 2x-1 )/( 2x+1 ) */
|
||||
e -= 1;
|
||||
z = x - 0.5L;
|
||||
y = 0.5L * z + 0.5L;
|
||||
}
|
||||
else
|
||||
{ /* 2 (x-1)/(x+1) */
|
||||
z = x - 0.5L;
|
||||
z -= 0.5L;
|
||||
y = 0.5L * x + 0.5L;
|
||||
}
|
||||
x = z / y;
|
||||
z = x * x;
|
||||
y = x * (z * neval (z, R, 5) / deval (z, S, 5));
|
||||
goto done;
|
||||
}
|
||||
|
||||
|
||||
/* logarithm using log(1+x) = x - .5x**2 + x**3 P(x)/Q(x) */
|
||||
|
||||
if (x < SQRTH)
|
||||
{
|
||||
e -= 1;
|
||||
x = 2.0 * x - 1.0L; /* 2x - 1 */
|
||||
}
|
||||
else
|
||||
{
|
||||
x = x - 1.0L;
|
||||
}
|
||||
z = x * x;
|
||||
y = x * (z * neval (x, P, 12) / deval (x, Q, 11));
|
||||
y = y - 0.5 * z;
|
||||
|
||||
done:
|
||||
|
||||
/* Multiply log of fraction by log10(e)
|
||||
* and base 2 exponent by log10(2).
|
||||
*/
|
||||
z = y * L10EB;
|
||||
z += x * L10EB;
|
||||
z += e * L102B;
|
||||
z += y * L10EA;
|
||||
z += x * L10EA;
|
||||
z += e * L102A;
|
||||
return (z);
|
||||
}
|
||||
Loading…
Reference in New Issue
Block a user