1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19
.global atanf .type atanf,@function atanf: flds 4(%esp) mov 4(%esp),%eax add %eax,%eax cmp $0x01000000,%eax jb 1f fld1 fpatan ret # subnormal x, return x with underflow 1: fnstsw %ax and $16,%ax jnz 2f fld %st(0) fmul %st(1) fstps 4(%esp) 2: ret