1.global atan
 2.type atan,@function
 3atan:
 4	fldl 4(%esp)
 5	mov 8(%esp),%eax
 6	add %eax,%eax
 7	cmp $0x00200000,%eax
 8	jb 1f
 9	fld1
10	fpatan
11	fstpl 4(%esp)
12	fldl 4(%esp)
13	ret
14		# subnormal x, return x with underflow
151:	fsts 4(%esp)
16	ret