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authorAdhemerval Zanella <azanella@linux.vnet.ibm.com>2013-11-25 06:12:30 -0600
committerAdhemerval Zanella <azanella@linux.vnet.ibm.com>2013-11-25 06:34:41 -0600
commit41e8926aa4b7f17bc95984737ee82a254ad0911c (patch)
treef113bbedd0ec991ae1b9dddf3a36077e22d19815 /sysdeps/ieee754/ldbl-128ibm/e_expl.c
parent085b5ddfe301eb74bc9f824ff293f054c1c910b7 (diff)
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PowerPC: Set/restore rounding mode only when needed
This patch helps some math functions performance by adding the libc_fexxx variant of inline functions to handle both FPU round and exception set/restore and by using them on the libc_fexxx_ctx functions. It is based on already coded fexxx family functions for PPC with fpu. Here is the summary of performance improvements due this patch (measured on a POWER7 machine): Before: cos(): ITERS:9.5895e+07: TOTAL:5116.03Mcy, MAX:77.6cy, MIN:49.792cy, 18744 calls/Mcy exp(): ITERS:2.827e+07: TOTAL:5187.15Mcy, MAX:494.018cy, MIN:38.422cy, 5450.01 calls/Mcy pow(): ITERS:6.1705e+07: TOTAL:5144.26Mcy, MAX:171.95cy, MIN:29.935cy, 11994.9 calls/Mcy sin(): ITERS:8.6898e+07: TOTAL:5117.06Mcy, MAX:83.841cy, MIN:46.582cy, 16982 calls/Mcy tan(): ITERS:2.9473e+07: TOTAL:5115.39Mcy, MAX:191.017cy, MIN:172.352cy, 5761.63 calls/Mcy After: cos(): ITERS:2.05265e+08: TOTAL:5111.37Mcy, MAX:78.754cy, MIN:24.196cy, 40158.5 calls/Mcy exp(): ITERS:3.341e+07: TOTAL:5170.84Mcy, MAX:476.317cy, MIN:15.574cy, 6461.23 calls/Mcy pow(): ITERS:7.6153e+07: TOTAL:5129.1Mcy, MAX:147.5cy, MIN:30.916cy, 14847.2 calls/Mcy sin(): ITERS:1.58816e+08: TOTAL:5115.11Mcy, MAX:1490.39cy, MIN:22.341cy, 31048.4 calls/Mcy tan(): ITERS:3.4964e+07: TOTAL:5114.18Mcy, MAX:177.422cy, MIN:146.115cy, 6836.68 calls/Mcy
Diffstat (limited to 'sysdeps/ieee754/ldbl-128ibm/e_expl.c')
-rw-r--r--sysdeps/ieee754/ldbl-128ibm/e_expl.c31
1 files changed, 13 insertions, 18 deletions
diff --git a/sysdeps/ieee754/ldbl-128ibm/e_expl.c b/sysdeps/ieee754/ldbl-128ibm/e_expl.c
index f7c50bf..65ef185 100644
--- a/sysdeps/ieee754/ldbl-128ibm/e_expl.c
+++ b/sysdeps/ieee754/ldbl-128ibm/e_expl.c
@@ -134,18 +134,17 @@ static const long double C[] = {
long double
__ieee754_expl (long double x)
{
+ long double result, x22;
+ union ibm_extended_long_double ex2_u, scale_u;
+ int unsafe;
+
/* Check for usual case. */
if (isless (x, himark) && isgreater (x, lomark))
{
- int tval1, tval2, unsafe, n_i, exponent2;
- long double x22, n, result, xl;
- union ibm_extended_long_double ex2_u, scale_u;
- fenv_t oldenv;
-
- feholdexcept (&oldenv);
-#ifdef FE_TONEAREST
- fesetround (FE_TONEAREST);
-#endif
+ int tval1, tval2, n_i, exponent2;
+ long double n, xl;
+
+ SET_RESTORE_ROUND (FE_TONEAREST);
n = __roundl (x*M_1_LN2);
x = x-n*M_LN2_0;
@@ -201,11 +200,6 @@ __ieee754_expl (long double x)
less than 4.8e-39. */
x22 = x + x*x*(P1+x*(P2+x*(P3+x*(P4+x*(P5+x*P6)))));
- /* Return result. */
- fesetenv (&oldenv);
-
- result = x22 * ex2_u.ld + ex2_u.ld;
-
/* Now we can test whether the result is ultimate or if we are unsure.
In the later case we should probably call a mpn based routine to give
the ultimate result.
@@ -235,10 +229,6 @@ __ieee754_expl (long double x)
return __ieee754_expl_proc2 (origx);
}
*/
- if (!unsafe)
- return result;
- else
- return result * scale_u.ld;
}
/* Exceptional cases: */
else if (isless (x, himark))
@@ -253,5 +243,10 @@ __ieee754_expl (long double x)
else
/* Return x, if x is a NaN or Inf; or overflow, otherwise. */
return TWO1023*x;
+
+ result = x22 * ex2_u.ld + ex2_u.ld;
+ if (!unsafe)
+ return result;
+ return result * scale_u.ld;
}
strong_alias (__ieee754_expl, __expl_finite)