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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