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Replace the macro name NUM with INTERVALS. This change provides

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compatibility with the INTERVALS macro used in the soon-to-be-commmitted
expm1l() and someday-to-be-committed log*l() functions.

Add a comment into ld128/s_expl.c noting at gcc issue that was
deleted when rewriting ld80/e_expl.c as ld128/s_expl.c.

Requested by:	bde
Approved by:	das (mentor)
This commit is contained in:
Steve Kargl 2012-07-26 04:05:08 +00:00
parent f7cfe68f59
commit 8345cbd275
2 changed files with 16 additions and 15 deletions
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9
lib/msun/ld128/s_expl.c
View File

@ -35,6 +35,7 @@ __FBSDID("$FreeBSD$");
#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 const long double
@ -57,12 +58,12 @@ P9 = 2.75573192240103867817876199544468806e-6L,
P10 = 2.75573236172670046201884000197885520e-7L,
P11 = 2.50517544183909126492878226167697856e-8L;
#define NUM 128
#define INTERVALS 128
static const struct {
long double hi;
long double lo;
} s[NUM] = {
} s[INTERVALS] = {
0x1p0L, 0x0p0L,
0x1.0163da9fb33356d84a66aep0L, 0x3.36dcdfa4003ec04c360be2404078p-92L,
0x1.02c9a3e778060ee6f7cacap0L, 0x4.f7a29bde93d70a2cabc5cb89ba10p-92L,
@ -226,8 +227,8 @@ expl(long double x)
fn = x * INV_L + 0x1.8p112 - 0x1.8p112;
n = (int)fn;
n2 = (unsigned)n % NUM; /* Tang's j. */
k = (n - n2) / NUM;
n2 = (unsigned)n % INTERVALS; /* Tang's j. */
k = (n - n2) / INTERVALS;
r1 = x - fn * L1;
r2 = -fn * L2;

22
lib/msun/ld80/s_expl.c
View File

@ -36,7 +36,7 @@ __FBSDID("$FreeBSD$");
* in IEEE floating-point arithmetic," ACM Trans. Math. Soft., 15,
* 144-157 (1989).
*
* where the 32 table entries have been expanded to NUM (see below).
* where the 32 table entries have been expanded to INTERVALS (see below).
*/
#include <float.h>
@ -65,9 +65,9 @@ u_threshold = LD80C(0xb21dfe7f09e2baa9, 13, 1, -11399.4985314888605581L);
static const double __aligned(64)
/*
* ln2/NUM = L1+L2 (hi+lo decomposition for multiplication). L1 must have
* at least 22 (= log2(|LDBL_MIN_EXP-extras|) + log2(NUM)) lowest bits zero
* so that multiplication of it by n is exact.
* ln2/INTERVALS = L1+L2 (hi+lo decomposition for multiplication). L1 must
* have at least 22 (= log2(|LDBL_MIN_EXP-extras|) + log2(INTERVALS)) lowest
* bits zero so that multiplication of it by n is exact.
*/
L1 = 5.4152123484527692e-3, /* 0x162e42ff000000.0p-60 */
L2 = -3.2819649005320973e-13, /* -0x1718432a1b0e26.0p-94 */
@ -75,7 +75,7 @@ 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
* (0.002708 is ln2/(2*NUM) rounded up a little).
* (0.002708 is ln2/(2*INTERVALS) rounded up a little).
*/
P2 = 0.5,
P3 = 1.6666666666666119e-1, /* 0x15555555555490.0p-55 */
@ -84,16 +84,16 @@ P5 = 8.3333354987869413e-3, /* 0x1111115b789919.0p-59 */
P6 = 1.3888891738560272e-3; /* 0x16c16c651633ae.0p-62 */
/*
* 2^(i/NUM) for i in [0,NUM] is represented by two values where the
* first 47 (?!) bits of the significand is stored in hi and the next 53
* 2^(i/INTERVALS) for i in [0,INTERVALS] is represented by two values where
* the first 47 (?!) bits of the significand is stored in hi and the next 53
* bits are in lo.
*/
#define NUM 128
#define INTERVALS 128
static const struct {
double hi;
double lo;
} s[NUM] __aligned(16) = {
} s[INTERVALS] __aligned(16) = {
0x1p+0, 0x0p+0,
0x1.0163da9fb330p+0, 0x1.ab6c25335719bp-47,
0x1.02c9a3e77804p+0, 0x1.07737be56527cp-47,
@ -265,8 +265,8 @@ expl(long double x)
#else
n = (int)fn;
#endif
n2 = (unsigned)n % NUM; /* Tang's j. */
k = (n - n2) / NUM;
n2 = (unsigned)n % INTERVALS; /* Tang's j. */
k = (n - n2) / INTERVALS;
r1 = x - fn * L1;
r2 = -fn * L2;