summaryrefslogtreecommitdiff
path: root/sysdeps/i386/fpu/e_asin.S
diff options
context:
space:
mode:
authorJoseph Myers <joseph@codesourcery.com>2012-04-30 18:56:39 +0000
committerJoseph Myers <joseph@codesourcery.com>2012-04-30 18:56:39 +0000
commitadfbc8ac9e192b6e3007f7a47852df937afa2145 (patch)
tree09a345d547258a55e1d410065f9ca09a1bed480c /sysdeps/i386/fpu/e_asin.S
parent5ba3cc691c856e5c67a7d4cd4713f20a79f7ba81 (diff)
downloadglibc-adfbc8ac9e192b6e3007f7a47852df937afa2145.tar.gz
Fix x86 acos near 1 (bug 13942).
Diffstat (limited to 'sysdeps/i386/fpu/e_asin.S')
-rw-r--r--sysdeps/i386/fpu/e_asin.S10
1 files changed, 6 insertions, 4 deletions
diff --git a/sysdeps/i386/fpu/e_asin.S b/sysdeps/i386/fpu/e_asin.S
index a17e922b6d..9a44cb62ac 100644
--- a/sysdeps/i386/fpu/e_asin.S
+++ b/sysdeps/i386/fpu/e_asin.S
@@ -7,13 +7,15 @@
RCSID("$NetBSD: e_asin.S,v 1.4 1995/05/08 23:45:40 jtc Exp $")
-/* asin = atan (x / sqrt(1 - x^2)) */
+/* asin = atan (x / sqrt((1-x) (1+x))) */
ENTRY(__ieee754_asin)
fldl 4(%esp) /* x */
fld %st
- fmul %st(0) /* x^2 */
- fld1
- fsubp /* 1 - x^2 */
+ fld1 /* 1 : x : x */
+ fsubp /* 1 - x : x */
+ fld1 /* 1 : 1 - x : x */
+ fadd %st(2) /* 1 + x : 1 - x : x */
+ fmulp /* 1 - x^2 */
fsqrt /* sqrt (1 - x^2) */
fpatan
ret