mirror of
https://sourceware.org/git/glibc.git
synced 2024-09-20 08:30:00 +00:00
Start optimizing the use of the fenv interfaces in libm itself
This commit is contained in:
Ulrich Drepper
parent
83c7615c2d
commit
d38f1dba00
15
ChangeLog
15
ChangeLog
@ -1,3 +1,18 @@
|
||||
2011-10-18 Ulrich Drepper <drepper@gmail.com>
|
||||
|
||||
* math/math_private.h: Define defaults for libc_fegetround,
|
||||
libc_fegetroundf, libc_fegetroundl, libc_fesetround, libc_fesetroundf,
|
||||
libc_fesetroundl, libc_feholdexcept, libc_feholdexceptf,
|
||||
libc_feholdexceptl, libc_fesetenv, libc_fesetenvf, libc_fesetenvl.
|
||||
* sysdeps/ieee754/dbl-64/wordsize-64/s_nearbyint.c: Use
|
||||
libc_feholdexcept, libc_fesetround, libc_fesetenv instead of the
|
||||
standard functions.
|
||||
* sysdeps/ieee754/dbl-64/e_exp2.c: Likewise.
|
||||
Remove comments and hacks for old compiler versions.
|
||||
* sysdeps/x86_64/fpu/math_private.h: Define special versions of
|
||||
libc_fegetround, libc_fesetround, libc_feholdexcept, and
|
||||
libc_feholdexceptl.
|
||||
|
||||
2011-10-18 Andreas Schwab <schwab@redhat.com>
|
||||
|
||||
* sysdeps/x86_64/fpu/bits/fenv.h: Add C linkage markers.
|
||||
|
||||
@ -358,4 +358,26 @@ extern void __docos (double __x, double __dx, double __v[]);
|
||||
#define math_force_eval(x) __asm __volatile ("" : : "m" (x))
|
||||
#endif
|
||||
|
||||
|
||||
/* The standards only specify one variant of the fenv.h interfaces.
|
||||
But at least for some architectures we can be more efficient if we
|
||||
know what operations are going to be performed. Therefore we
|
||||
define additional interfaces. By default they refer to the normal
|
||||
interfaces. */
|
||||
#define libc_fegetround() fegetround ()
|
||||
#define libc_fegetroundf() fegetround ()
|
||||
#define libc_fegetroundl() fegetround ()
|
||||
|
||||
#define libc_fesetround(r) (void) fesetround (r)
|
||||
#define libc_fesetroundf(r) (void) fesetround (r)
|
||||
#define libc_fesetroundl(r) (void) fesetround (r)
|
||||
|
||||
#define libc_feholdexcept(e) (void) feholdexcept (e)
|
||||
#define libc_feholdexceptf(e) (void) feholdexcept (e)
|
||||
#define libc_feholdexceptl(e) (void) feholdexcept (e)
|
||||
|
||||
#define libc_fesetenv(e) (void) fesetenv (e)
|
||||
#define libc_fesetenvf(e) (void) fesetenv (e)
|
||||
#define libc_fesetenvl(e) (void) fesetenv (e)
|
||||
|
||||
#endif /* _MATH_PRIVATE_H_ */
|
||||
|
||||
@ -25,9 +25,6 @@
|
||||
17 (1), March 1991, pp. 26-45.
|
||||
It has been slightly modified to compute 2^x instead of e^x.
|
||||
*/
|
||||
#ifndef _GNU_SOURCE
|
||||
#define _GNU_SOURCE
|
||||
#endif
|
||||
#include <stdlib.h>
|
||||
#include <float.h>
|
||||
#include <ieee754.h>
|
||||
@ -38,13 +35,8 @@
|
||||
|
||||
#include "t_exp2.h"
|
||||
|
||||
/* XXX I know the assembler generates a warning about incorrect section
|
||||
attributes. But without the attribute here the compiler places the
|
||||
constants in the .data section. Ideally the constant is placed in
|
||||
.rodata.cst8 so that it can be merged, but gcc sucks, it ICEs when
|
||||
we try to force this section on it. --drepper */
|
||||
static const volatile double TWO1023 = 8.988465674311579539e+307;
|
||||
static const volatile double TWOM1000 = 9.3326361850321887899e-302;
|
||||
static const double TWO1023 = 8.988465674311579539e+307;
|
||||
static const double TWOM1000 = 9.3326361850321887899e-302;
|
||||
|
||||
double
|
||||
__ieee754_exp2 (double x)
|
||||
@ -72,10 +64,10 @@ __ieee754_exp2 (double x)
|
||||
union ieee754_double ex2_u, scale_u;
|
||||
fenv_t oldenv;
|
||||
|
||||
feholdexcept (&oldenv);
|
||||
libc_feholdexcept (&oldenv);
|
||||
#ifdef FE_TONEAREST
|
||||
/* If we don't have this, it's too bad. */
|
||||
fesetround (FE_TONEAREST);
|
||||
libc_fesetround (FE_TONEAREST);
|
||||
#endif
|
||||
|
||||
/* 1. Argument reduction.
|
||||
@ -120,9 +112,10 @@ __ieee754_exp2 (double x)
|
||||
* x + .055504110254308625)
|
||||
* x + .240226506959100583)
|
||||
* x + .69314718055994495) * ex2_u.d;
|
||||
math_opt_barrier (x22);
|
||||
|
||||
/* 5. Return (2^x2-1) * 2^(t/512+e+ex) + 2^(t/512+e+ex). */
|
||||
fesetenv (&oldenv);
|
||||
libc_fesetenv (&oldenv);
|
||||
|
||||
result = x22 * x + ex2_u.d;
|
||||
|
||||
|
||||
@ -24,22 +24,14 @@
|
||||
#include "math.h"
|
||||
#include "math_private.h"
|
||||
|
||||
#ifdef __STDC__
|
||||
static const double
|
||||
#else
|
||||
static double
|
||||
#endif
|
||||
TWO52[2]={
|
||||
4.50359962737049600000e+15, /* 0x43300000, 0x00000000 */
|
||||
-4.50359962737049600000e+15, /* 0xC3300000, 0x00000000 */
|
||||
};
|
||||
|
||||
#ifdef __STDC__
|
||||
double __nearbyint(double x)
|
||||
#else
|
||||
double __nearbyint(x)
|
||||
double x;
|
||||
#endif
|
||||
double
|
||||
__nearbyint(double x)
|
||||
{
|
||||
fenv_t env;
|
||||
int64_t i0,sx;
|
||||
@ -47,20 +39,19 @@ TWO52[2]={
|
||||
EXTRACT_WORDS64(i0,x);
|
||||
sx = (i0>>63)&1;
|
||||
j0 = ((i0>>52)&0x7ff)-0x3ff;
|
||||
if(j0<52) {
|
||||
if(__builtin_expect(j0<52, 1)) {
|
||||
if(j0<0) {
|
||||
if((i0&UINT64_C(0x7fffffffffffffff))==0) return x;
|
||||
uint64_t i = i0 & UINT64_C(0xfffffffffffff);
|
||||
i0 &= UINT64_C(0xfffe000000000000);
|
||||
i0 |= (((i|-i) >> 12) & UINT64_C(0x8000000000000));
|
||||
INSERT_WORDS64(x,i0);
|
||||
feholdexcept (&env);
|
||||
libc_feholdexcept (&env);
|
||||
double w = TWO52[sx]+x;
|
||||
double t = w-TWO52[sx];
|
||||
fesetenv (&env);
|
||||
EXTRACT_WORDS64(i0,t);
|
||||
INSERT_WORDS64(t,(i0&UINT64_C(0x7fffffffffffffff))|(sx<<63));
|
||||
return t;
|
||||
math_opt_barrier(t);
|
||||
libc_fesetenv (&env);
|
||||
return copysign(t, x);
|
||||
} else {
|
||||
uint64_t i = UINT64_C(0x000fffffffffffff)>>j0;
|
||||
if((i0&i)==0) return x; /* x is integral */
|
||||
@ -73,10 +64,11 @@ TWO52[2]={
|
||||
else return x; /* x is integral */
|
||||
}
|
||||
INSERT_WORDS64(x,i0);
|
||||
feholdexcept (&env);
|
||||
libc_feholdexcept (&env);
|
||||
double w = TWO52[sx]+x;
|
||||
double t = w-TWO52[sx];
|
||||
fesetenv (&env);
|
||||
math_opt_barrier (t);
|
||||
libc_fesetenv (&env);
|
||||
return t;
|
||||
}
|
||||
weak_alias (__nearbyint, nearbyint)
|
||||
|
||||
@ -118,3 +118,45 @@ do { \
|
||||
__res; })
|
||||
# endif
|
||||
#endif
|
||||
|
||||
|
||||
/* Specialized variants of the <fenv.h> interfaces which only handle
|
||||
either the FPU or the SSE unit. */
|
||||
#undef libc_fegetround
|
||||
#define libc_fegetround() \
|
||||
({ \
|
||||
unsigned int mxcsr; \
|
||||
asm volatile ("stmxcsr %0" : "=m" (*&mxcsr)); \
|
||||
(mxcsr & 0x6000) >> 3; \
|
||||
})
|
||||
// #define libc_fegetroundf() fegetround ()
|
||||
// #define libc_fegetroundl() fegetround ()
|
||||
|
||||
#undef libc_fesetround
|
||||
#define libc_fesetround(r) \
|
||||
do { \
|
||||
unsigned int mxcsr; \
|
||||
asm ("stmxcsr %0" : "=m" (*&mxcsr)); \
|
||||
mxcsr = (mxcsr & ~0x6000) | ((r) << 3); \
|
||||
asm volatile ("ldmxcsr %0" : : "m" (*&mxcsr)); \
|
||||
} while (0)
|
||||
// #define libc_fesetroundf(r) (void) fesetround (r)
|
||||
// #define libc_fesetroundl(r) (void) fesetround (r)
|
||||
|
||||
#undef libc_feholdexcept
|
||||
#define libc_feholdexcept(e) \
|
||||
do { \
|
||||
unsigned int mxcsr; \
|
||||
asm ("stmxcsr %0" : "=m" (*&mxcsr)); \
|
||||
(e)->__mxcsr = mxcsr; \
|
||||
mxcsr = (mxcsr | 0x1f80) & ~0x3f; \
|
||||
asm volatile ("ldmxcsr %0" : : "m" (*&mxcsr)); \
|
||||
} while (0)
|
||||
// #define libc_feholdexceptf(e) (void) feholdexcept (e)
|
||||
// #define libc_feholdexceptl(e) (void) feholdexcept (e)
|
||||
|
||||
#undef libc_fesetenv
|
||||
#define libc_fesetenv(e) \
|
||||
asm volatile ("ldmxcsr %0" : : "m" ((e)->__mxcsr))
|
||||
// #define libc_fesetenvf(e) (void) fesetenv (e)
|
||||
// #define libc_fesetenvl(e) (void) fesetenv (e)
|
||||
|
||||
Loading…
Reference in New Issue
Block a user