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Fix exp in non-default rounding modes (bug 3976).

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This commit is contained in:
Joseph Myers 2012-03-02 15:12:53 +00:00
parent b1eeb65d49
commit 28afd92dbd
5 changed files with 268 additions and 14 deletions
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14
ChangeLog
View File

@ -1,3 +1,17 @@
2012-03-02 Joseph Myers <joseph@codesourcery.com>
[BZ #3976]
* sysdeps/ieee754/dbl-64/e_exp.c: Include <fenv.h>.
(__ieee754_exp): Save and restore rounding mode and use
round-to-nearest for all computations.
* math/libm-test.inc (exp_test_tonearest): New function.
(exp_test_towardzero): Likewise.
(exp_test_downward): Likewise.
(exp_test_upward): Likewise.
(main): Call the new functions.
* sysdeps/i386/fpu/libm-test-ulps: Update.
* sysdeps/x86_64/fpu/libm-test-ulps: Likewise.
2012-03-01 Chris Demetriou <cgd@google.com>
* sysdeps/gnu/errlist-compat.awk: Don't depend on AWK internals to

112
math/libm-test.inc
View File

@ -2531,6 +2531,114 @@ exp_test (void)
}
static void
exp_test_tonearest (void)
{
int save_round_mode;
errno = 0;
FUNC(exp) (0);
if (errno == ENOSYS)
/* Function not implemented. */
return;
START (exp_tonearest);
save_round_mode = fegetround ();
if (!fesetround (FE_TONEAREST))
{
TEST_f_f (exp, 1, M_El);
TEST_f_f (exp, 2, M_E2l);
TEST_f_f (exp, 3, M_E3l);
}
fesetround (save_round_mode);
END (exp_tonearest);
}
static void
exp_test_towardzero (void)
{
int save_round_mode;
errno = 0;
FUNC(exp) (0);
if (errno == ENOSYS)
/* Function not implemented. */
return;
START (exp_towardzero);
save_round_mode = fegetround ();
if (!fesetround (FE_TOWARDZERO))
{
TEST_f_f (exp, 1, M_El);
TEST_f_f (exp, 2, M_E2l);
TEST_f_f (exp, 3, M_E3l);
}
fesetround (save_round_mode);
END (exp_towardzero);
}
static void
exp_test_downward (void)
{
int save_round_mode;
errno = 0;
FUNC(exp) (0);
if (errno == ENOSYS)
/* Function not implemented. */
return;
START (exp_downward);
save_round_mode = fegetround ();
if (!fesetround (FE_DOWNWARD))
{
TEST_f_f (exp, 1, M_El);
TEST_f_f (exp, 2, M_E2l);
TEST_f_f (exp, 3, M_E3l);
}
fesetround (save_round_mode);
END (exp_downward);
}
static void
exp_test_upward (void)
{
int save_round_mode;
errno = 0;
FUNC(exp) (0);
if (errno == ENOSYS)
/* Function not implemented. */
return;
START (exp_upward);
save_round_mode = fegetround ();
if (!fesetround (FE_UPWARD))
{
TEST_f_f (exp, 1, M_El);
TEST_f_f (exp, 2, M_E2l);
TEST_f_f (exp, 3, M_E3l);
}
fesetround (save_round_mode);
END (exp_upward);
}
static void
exp10_test (void)
{
@ -6400,6 +6508,10 @@ main (int argc, char **argv)
/* Exponential and logarithmic functions: */
exp_test ();
exp_test_tonearest ();
exp_test_towardzero ();
exp_test_downward ();
exp_test_upward ();
exp10_test ();
exp2_test ();
expm1_test ();

67
sysdeps/i386/fpu/libm-test-ulps
View File

@ -460,6 +460,51 @@ Test "exp10 (3) == 1000":
ildouble: 8
ldouble: 8
# exp_downward
Test "exp_downward (1) == e":
ildouble: 1
ldouble: 1
Test "exp_downward (2) == e^2":
double: 1
float: 1
idouble: 1
ifloat: 1
ildouble: 2
ldouble: 2
Test "exp_downward (3) == e^3":
double: 1
float: 1
idouble: 1
ifloat: 1
ildouble: 1
ldouble: 1
# exp_towardzero
Test "exp_towardzero (1) == e":
ildouble: 1
ldouble: 1
Test "exp_towardzero (2) == e^2":
double: 1
float: 1
idouble: 1
ifloat: 1
ildouble: 2
ldouble: 2
Test "exp_towardzero (3) == e^3":
double: 1
float: 1
idouble: 1
ifloat: 1
ildouble: 1
ldouble: 1
# exp_upward
Test "exp_upward (1) == e":
double: 1
float: 1
idouble: 1
ifloat: 1
# expm1
Test "expm1 (1) == M_El - 1.0":
ildouble: 1
@ -1184,6 +1229,28 @@ Function: "exp10":
ildouble: 8
ldouble: 8
Function: "exp_downward":
double: 1
float: 1
idouble: 1
ifloat: 1
ildouble: 2
ldouble: 2
Function: "exp_towardzero":
double: 1
float: 1
idouble: 1
ifloat: 1
ildouble: 2
ldouble: 2
Function: "exp_upward":
double: 1
float: 1
idouble: 1
ifloat: 1
Function: "expm1":
ildouble: 1
ldouble: 1

38
sysdeps/ieee754/dbl-64/e_exp.c
View File

@ -1,7 +1,7 @@
/*
* IBM Accurate Mathematical Library
* written by International Business Machines Corp.
* Copyright (C) 2001, 2011 Free Software Foundation
* Copyright (C) 2001-2012 Free Software Foundation
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as published by
@ -38,6 +38,7 @@
#include "MathLib.h"
#include "uexp.tbl"
#include "math_private.h"
#include <fenv.h>
#ifndef SECTION
# define SECTION
@ -58,6 +59,10 @@ __ieee754_exp(double x) {
int4 k;
#endif
int4 i,j,m,n,ex;
fenv_t env;
double retval;
libc_feholdexcept_setround (&env, FE_TONEAREST);
junk1.x = x;
m = junk1.i[HIGH_HALF];
@ -90,18 +95,19 @@ __ieee754_exp(double x) {
rem=(bet + bet*eps)+al*eps;
res = al + rem;
cor = (al - res) + rem;
if (res == (res+cor*err_0)) return res*binexp.x;
else return __slowexp(x); /*if error is over bound */
if (res == (res+cor*err_0)) { retval = res*binexp.x; goto ret; }
else { retval = __slowexp(x); goto ret; } /*if error is over bound */
}
if (n <= smallint) return 1.0;
if (n <= smallint) { retval = 1.0; goto ret; }
if (n >= badint) {
if (n > infint) return(x+x); /* x is NaN */
if (n < infint) return ( (x>0) ? (hhuge*hhuge) : (tiny*tiny) );
if (n > infint) { retval = x+x; goto ret; } /* x is NaN */
if (n < infint) { retval = (x>0) ? (hhuge*hhuge) : (tiny*tiny); goto ret; }
/* x is finite, cause either overflow or underflow */
if (junk1.i[LOW_HALF] != 0) return (x+x); /* x is NaN */
return ((x>0)?inf.x:zero ); /* |x| = inf; return either inf or 0 */
if (junk1.i[LOW_HALF] != 0) { retval = x+x; goto ret; } /* x is NaN */
retval = (x>0)?inf.x:zero; /* |x| = inf; return either inf or 0 */
goto ret;
}
y = x*log2e.x + three51.x;
@ -126,8 +132,8 @@ __ieee754_exp(double x) {
if (res < 1.0) {res+=res; cor+=cor; ex-=1;}
if (ex >=-1022) {
binexp.i[HIGH_HALF] = (1023+ex)<<20;
if (res == (res+cor*err_0)) return res*binexp.x;
else return __slowexp(x); /*if error is over bound */
if (res == (res+cor*err_0)) { retval = res*binexp.x; goto ret; }
else { retval = __slowexp(x); goto ret; } /*if error is over bound */
}
ex = -(1022+ex);
binexp.i[HIGH_HALF] = (1023-ex)<<20;
@ -140,15 +146,19 @@ __ieee754_exp(double x) {
cor = (t-res)+y;
if (res == (res + eps*cor))
{ binexp.i[HIGH_HALF] = 0x00100000;
return (res-1.0)*binexp.x;
retval = (res-1.0)*binexp.x;
goto ret;
}
else return __slowexp(x); /* if error is over bound */
else { retval = __slowexp(x); goto ret; } /* if error is over bound */
}
else {
binexp.i[HIGH_HALF] =(junk1.i[LOW_HALF]+767)<<20;
if (res == (res+cor*err_0)) return res*binexp.x*t256.x;
else return __slowexp(x);
if (res == (res+cor*err_0)) { retval = res*binexp.x*t256.x; goto ret; }
else { retval = __slowexp(x); goto ret; }
}
ret:
libc_feupdateenv (&env);
return retval;
}
#ifndef __ieee754_exp
strong_alias (__ieee754_exp, __exp_finite)

51
sysdeps/x86_64/fpu/libm-test-ulps
View File

@ -512,6 +512,41 @@ ifloat: 2
ildouble: 8
ldouble: 8
# exp_downward
Test "exp_downward (1) == e":
ildouble: 1
ldouble: 1
Test "exp_downward (2) == e^2":
float: 1
ifloat: 1
ildouble: 2
ldouble: 2
Test "exp_downward (3) == e^3":
float: 1
ifloat: 1
ildouble: 1
ldouble: 1
# exp_towardzero
Test "exp_towardzero (1) == e":
ildouble: 1
ldouble: 1
Test "exp_towardzero (2) == e^2":
float: 1
ifloat: 1
ildouble: 2
ldouble: 2
Test "exp_towardzero (3) == e^3":
float: 1
ifloat: 1
ildouble: 1
ldouble: 1
# exp_upward
Test "exp_upward (1) == e":
float: 1
ifloat: 1
# expm1
Test "expm1 (0.75) == 1.11700001661267466854536981983709561":
double: 1
@ -1275,6 +1310,22 @@ ifloat: 2
ildouble: 8
ldouble: 8
Function: "exp_downward":
float: 1
ifloat: 1
ildouble: 2
ldouble: 2
Function: "exp_towardzero":
float: 1
ifloat: 1
ildouble: 2
ldouble: 2
Function: "exp_upward":
float: 1
ifloat: 1
Function: "expm1":
double: 1
float: 1