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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 | |
| 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')
| -rw-r--r-- | sysdeps/i386/fpu/e_acos.S | 10 | ||||
| -rw-r--r-- | sysdeps/i386/fpu/e_acosl.c | 8 | ||||
| -rw-r--r-- | sysdeps/i386/fpu/e_asin.S | 10 | ||||
| -rw-r--r-- | sysdeps/i386/fpu/libm-test-ulps | 12 |
4 files changed, 29 insertions, 11 deletions
diff --git a/sysdeps/i386/fpu/e_acos.S b/sysdeps/i386/fpu/e_acos.S index d10a054..586c7fc 100644 --- a/sysdeps/i386/fpu/e_acos.S +++ b/sysdeps/i386/fpu/e_acos.S @@ -7,13 +7,15 @@ RCSID("$NetBSD: e_acos.S,v 1.4 1995/05/08 23:44:37 jtc Exp $") -/* acos = atan (sqrt(1 - x^2) / x) */ +/* acos = atan (sqrt((1-x) (1+x)) / x) */ ENTRY(__ieee754_acos) fldl 4(%esp) /* x */ fld %st /* x : x */ - fmul %st(0) /* x^2 : x */ - fld1 /* 1 : x^2 : x */ - fsubp /* 1 - x^2 : x */ + fld1 /* 1 : x : x */ + fsubp /* 1 - x : x */ + fld1 /* 1 : 1 - x : x */ + fadd %st(2) /* 1 + x : 1 - x : x */ + fmulp /* 1 - x^2 : x */ fsqrt /* sqrt (1 - x^2) : x */ fabs fxch %st(1) /* x : sqrt (1 - x^2) */ diff --git a/sysdeps/i386/fpu/e_acosl.c b/sysdeps/i386/fpu/e_acosl.c index d249d5a..ab08931 100644 --- a/sysdeps/i386/fpu/e_acosl.c +++ b/sysdeps/i386/fpu/e_acosl.c @@ -12,11 +12,13 @@ __ieee754_acosl (long double x) { long double res; - /* acosl = atanl (sqrtl(1 - x^2) / x) */ + /* acosl = atanl (sqrtl((1-x) (1+x)) / x) */ asm ( "fld %%st\n" - "fmul %%st(0)\n" /* x^2 */ "fld1\n" - "fsubp\n" /* 1 - x^2 */ + "fsubp\n" + "fld1\n" + "fadd %%st(2)\n" + "fmulp\n" /* 1 - x^2 */ "fsqrt\n" /* sqrtl (1 - x^2) */ "fabs\n" "fxch %%st(1)\n" diff --git a/sysdeps/i386/fpu/e_asin.S b/sysdeps/i386/fpu/e_asin.S index a17e922..9a44cb6 100644 --- a/sysdeps/i386/fpu/e_asin.S +++ b/sysdeps/i386/fpu/e_asin.S @@ -7,13 +7,15 @@ RCSID("$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 diff --git a/sysdeps/i386/fpu/libm-test-ulps b/sysdeps/i386/fpu/libm-test-ulps index fdaff35..a49a69d 100644 --- a/sysdeps/i386/fpu/libm-test-ulps +++ b/sysdeps/i386/fpu/libm-test-ulps @@ -80,6 +80,12 @@ ldouble: 1 Test "asin (-0.5) == -pi/6": ildouble: 1 ldouble: 1 +Test "asin (-0x0.ffffffff8p0) == -1.5707810680058339712015850710748035974710": +ildouble: 1 +ldouble: 1 +Test "asin (-0x0.ffffffp0) == -1.5704510598101804156437184421571127056013": +ildouble: 1 +ldouble: 1 Test "asin (-1.0) == -pi/2": ildouble: 1 ldouble: 1 @@ -89,6 +95,12 @@ ldouble: 1 Test "asin (0.75) == 0.848062078981481008052944338998418080": ildouble: 1 ldouble: 1 +Test "asin (0x0.ffffffff8p0) == 1.5707810680058339712015850710748035974710": +ildouble: 1 +ldouble: 1 +Test "asin (0x0.ffffffp0) == 1.5704510598101804156437184421571127056013": +ildouble: 1 +ldouble: 1 Test "asin (1.0) == pi/2": ildouble: 1 ldouble: 1 |