d/freebsd-dev
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

* ld80/s_expl.c:

Browse Source 
. Guard a comment from reformatting by indent(1).
  . Re-order variables in declarations to alphabetical order.
  . Remove a banal comment.

* ld128/s_expl.c:
  . Add a comment to point to ld80/s_expl.c for implementation details.
  . Move the #define of INTERVAL to reduce the diff with ld80/s_expl.c.
  . twom10000 does not need to be volatile, so move its declaration.
  . Re-order variables in declarations to alphabetical order.
  . Add a comment that describes the argument reduction.
  . Remove the same banal comment found in ld80/s_expl.c.

Reviewed by:	bde
Approved by:	das (mentor)
This commit is contained in:
Steve Kargl 2012-09-23 18:06:27 +00:00
parent 0ad5179dee
commit 8f647ffd7f
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=240864
2 changed files with 17 additions and 13 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

22
lib/msun/ld128/s_expl.c
View File

@ -27,24 +27,29 @@
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
/*
* ld128 version of s_expl.c. See ../ld80/s_expl.c for most comments.
*/
#include <float.h>
#include "fpmath.h"
#include "math.h"
#include "math_private.h"
#define INTERVALS 128
#define BIAS (LDBL_MAX_EXP - 1)
/* XXX Prevent gcc from erroneously constant folding this: */
static volatile const long double twom10000 = 0x1p-10000L, tiny = 0x1p-10000L;
static volatile const long double tiny = 0x1p-10000L;
static const long double
huge = 0x1p10000L,
o_threshold = 11356.523406294143949491931077970763428L,
u_threshold = -11433.462743336297878837243843452621503L,
INV_L = 1.84664965233787316142070359168242182e+02L,
L1 = 5.41521234812457272982212595914567508e-03L,
L2 = -1.02536706388947310094527932552595546e-29L,
INV_L = 1.84664965233787316142070359168242182e+02L;
huge = 0x1p10000L,
o_threshold = 11356.523406294143949491931077970763428L,
twom10000 = 0x1p-10000L,
u_threshold = -11433.462743336297878837243843452621503L;
static const long double
P2 = 5.00000000000000000000000000000000000e-1L,
@ -58,8 +63,6 @@ P9 = 2.75573192240103867817876199544468806e-6L,
P10 = 2.75573236172670046201884000197885520e-7L,
P11 = 2.50517544183909126492878226167697856e-8L;
#define INTERVALS 128
static const struct {
long double hi;
long double lo;
@ -225,9 +228,10 @@ expl(long double x)
return (1.0L + x);
}
/* Reduce x to (k*ln2 + midpoint[n2] + r1 + r2). */
fn = x * INV_L + 0x1.8p112 - 0x1.8p112;
n = (int)fn;
n2 = (unsigned)n % INTERVALS; /* Tang's j. */
n2 = (unsigned)n % INTERVALS;
k = (n - n2) / INTERVALS;
r1 = x - fn * L1;
r2 = -fn * L2;

8
lib/msun/ld80/s_expl.c
View File

@ -29,7 +29,7 @@
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
/*
/*-
* Compute the exponential of x for Intel 80-bit format. This is based on:
*
* PTP Tang, "Table-driven implementation of the exponential function
@ -70,9 +70,9 @@ static const double __aligned(64)
* have at least 22 (= log2(|LDBL_MIN_EXP-extras|) + log2(INTERVALS)) lowest
* bits zero so that multiplication of it by n is exact.
*/
INV_L = 1.8466496523378731e+2, /* 0x171547652b82fe.0p-45 */
L1 = 5.4152123484527692e-3, /* 0x162e42ff000000.0p-60 */
L2 = -3.2819649005320973e-13, /* -0x1718432a1b0e26.0p-94 */
INV_L = 1.8466496523378731e+2, /* 0x171547652b82fe.0p-45 */
/*
* Domain [-0.002708, 0.002708], range ~[-5.7136e-24, 5.7110e-24]:
* |exp(x) - p(x)| < 2**-77.2
@ -231,7 +231,7 @@ long double
expl(long double x)
{
union IEEEl2bits u, v;
long double fn, r, r1, r2, q, t, t23, t45, twopk, twopkp10000, z;
long double fn, q, r, r1, r2, t, t23, t45, twopk, twopkp10000, z;
int k, n, n2;
uint16_t hx, ix;
@ -268,7 +268,7 @@ expl(long double x)
#else
n = (int)fn;
#endif
n2 = (unsigned)n % INTERVALS; /* Tang's j. */
n2 = (unsigned)n % INTERVALS;
k = (n - n2) / INTERVALS;
r1 = x - fn * L1;
r2 = -fn * L2;