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| author | Joseph Myers <joseph@codesourcery.com> | 2012-04-30 18:56:39 +0000 |
|---|---|---|
| committer | Joseph Myers <joseph@codesourcery.com> | 2012-04-30 18:56:39 +0000 |
| commit | adfbc8ac9e192b6e3007f7a47852df937afa2145 (patch) | |
| tree | 09a345d547258a55e1d410065f9ca09a1bed480c /sysdeps/i386/fpu/e_acosl.c | |
| parent | 5ba3cc691c856e5c67a7d4cd4713f20a79f7ba81 (diff) | |
| download | glibc-adfbc8ac9e192b6e3007f7a47852df937afa2145.zip glibc-adfbc8ac9e192b6e3007f7a47852df937afa2145.tar.gz glibc-adfbc8ac9e192b6e3007f7a47852df937afa2145.tar.bz2 | |
Fix x86 acos near 1 (bug 13942).
Diffstat (limited to 'sysdeps/i386/fpu/e_acosl.c')
| -rw-r--r-- | sysdeps/i386/fpu/e_acosl.c | 8 |
1 files changed, 5 insertions, 3 deletions
diff --git a/sysdeps/i386/fpu/e_acosl.c b/sysdeps/i386/fpu/e_acosl.c index d249d5a..ab08931 100644 --- a/sysdeps/i386/fpu/e_acosl.c +++ b/sysdeps/i386/fpu/e_acosl.c @@ -12,11 +12,13 @@ __ieee754_acosl (long double x) { long double res; - /* acosl = atanl (sqrtl(1 - x^2) / x) */ + /* acosl = atanl (sqrtl((1-x) (1+x)) / x) */ asm ( "fld %%st\n" - "fmul %%st(0)\n" /* x^2 */ "fld1\n" - "fsubp\n" /* 1 - x^2 */ + "fsubp\n" + "fld1\n" + "fadd %%st(2)\n" + "fmulp\n" /* 1 - x^2 */ "fsqrt\n" /* sqrtl (1 - x^2) */ "fabs\n" "fxch %%st(1)\n" |