# use acos(x) = atan2(fabs(sqrt((1-x)*(1+x))), x)

.global acosf
.type acosf,@function
acosf:
        flds 4(%esp)
        jmp 1f

.global acosl
.type acosl,@function
acosl:
        fldt 4(%esp)
        jmp 1f

.global acos
.type acos,@function
acos:
        fldl 4(%esp)
1:      fld %st(0)
        fld1
        fsub %st(0),%st(1)
        fadd %st(2)
        fmulp
        fsqrt
        fabs         # fix sign of zero (matters in downward rounding mode)
        fxch %st(1)
        fpatan
        ret