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Diffstat (limited to 'src/math/i386/acos.s')
| -rw-r--r-- | src/math/i386/acos.s | 18 |
1 files changed, 8 insertions, 10 deletions
diff --git a/src/math/i386/acos.s b/src/math/i386/acos.s index bfff0c5c..47f365ef 100644 --- a/src/math/i386/acos.s +++ b/src/math/i386/acos.s @@ -1,3 +1,5 @@ +# use acos(x) = atan2(fabs(sqrt((1-x)*(1+x))), x) + .global acosf .type acosf,@function acosf: @@ -14,17 +16,13 @@ acosl: .type acos,@function acos: fldl 4(%esp) -1: fld1 - fld %st(1) +1: fld %st(0) fld1 - fsubp - fsqrt - fxch %st(2) - faddp + fsub %st(0),%st(1) + fadd %st(2) + fmulp fsqrt + fabs # fix sign of zero (matters in downward rounding mode) + fxch %st(1) fpatan - fld1 - fld1 - faddp - fmulp ret |