.global atan
.type atan,@function
atan:
        fldl 4(%esp)
        mov 8(%esp),%eax
        add %eax,%eax
        cmp $0x00200000,%eax
        jb 1f
        fld1
        fpatan
        ret
                # subnormal x, return x with underflow
1:      fsts 4(%esp)
        ret