1# use acos(x) = atan2(fabs(sqrt((1-x)*(1+x))), x)
 2
 3.global acos
 4.type acos,@function
 5acos:
 6	fldl 4(%esp)
 7	fld %st(0)
 8	fld1
 9	fsub %st(0),%st(1)
10	fadd %st(2)
11	fmulp
12	fsqrt
13	fabs         # fix sign of zero (matters in downward rounding mode)
14	fxch %st(1)
15	fpatan
16	fstpl 4(%esp)
17	fldl 4(%esp)
18	ret