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authorAndreas Schwab <schwab@linux-m68k.org>2012-05-25 11:57:33 +0200
committerAndreas Schwab <schwab@linux-m68k.org>2012-05-26 13:53:22 +0200
commit25dbcb277a9dea5f241c0b888a30b9341310d941 (patch)
tree74c7933f325f44fed6f2f15fd87c59fd4752be37 /sysdeps/ieee754/dbl-64/s_logb.c
parentd81dcb356909937b0c8e9c69ff0be27f51aaa07a (diff)
downloadglibc-25dbcb277a9dea5f241c0b888a30b9341310d941.tar.gz
Optimize handling of denormals in logb/logbf/logbl
Diffstat (limited to 'sysdeps/ieee754/dbl-64/s_logb.c')
-rw-r--r--sysdeps/ieee754/dbl-64/s_logb.c10
1 files changed, 6 insertions, 4 deletions
diff --git a/sysdeps/ieee754/dbl-64/s_logb.c b/sysdeps/ieee754/dbl-64/s_logb.c
index baa35e14d8..17aa94b755 100644
--- a/sysdeps/ieee754/dbl-64/s_logb.c
+++ b/sysdeps/ieee754/dbl-64/s_logb.c
@@ -34,10 +34,12 @@ __logb (double x)
{
/* POSIX specifies that denormal number is treated as
though it were normalized. */
- int m1 = (ix == 0) ? 0 : __builtin_clz (ix);
- int m2 = (lx == 0) ? 0 : __builtin_clz (lx);
- int ma = (m1 == 0) ? m2 + 32 : m1;
- return -1022.0 + (double)(11 - ma);
+ int ma;
+ if (ix == 0)
+ ma = __builtin_clz (lx) + 32;
+ else
+ ma = __builtin_clz (ix);
+ rix -= ma - 12;
}
return (double) (rix - 1023);
}