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| author | nsz <nsz@port70.net> | 2012-04-04 17:34:28 +0200 |
|---|---|---|
| committer | nsz <nsz@port70.net> | 2012-04-04 17:34:28 +0200 |
| commit | 37eaec3ad396ea4502f4aea2395b3b5f5f69a1c6 (patch) | |
| tree | 4a5aef1ff345c6b529589c9d1ffb181c9a779b30 | |
| parent | 5bd0ab8af66829af74ed80cac767ce1c041fd767 (diff) | |
| download | musl-37eaec3ad396ea4502f4aea2395b3b5f5f69a1c6.tar.gz | |
math: fix x86 asin accuracy
use (1-x)*(1+x) instead of (1-x*x) in asin.s
the later can be inaccurate with upward rounding when x is close to 1
| -rw-r--r-- | src/math/i386/asin.s | 5 | ||||
| -rw-r--r-- | src/math/x86_64/asinl.s | 6 |
2 files changed, 6 insertions, 5 deletions
diff --git a/src/math/i386/asin.s b/src/math/i386/asin.s index cab7bfc8..932c7542 100644 --- a/src/math/i386/asin.s +++ b/src/math/i386/asin.s @@ -15,9 +15,10 @@ asinl: asin: fldl 4(%esp) 1: fld %st(0) - fmul %st(0) fld1 - fsubp %st(1) + fsub %st(0),%st(1) + fadd %st(2) + fmulp fsqrt fpatan ret diff --git a/src/math/x86_64/asinl.s b/src/math/x86_64/asinl.s index 83c392f7..ed212d9a 100644 --- a/src/math/x86_64/asinl.s +++ b/src/math/x86_64/asinl.s @@ -3,10 +3,10 @@ asinl: fldt 8(%rsp) 1: fld %st(0) - fmul %st(0) fld1 - fsubp %st(1) + fsub %st(0),%st(1) + fadd %st(2) + fmulp fsqrt fpatan ret - |