ref: 6901f0c40f4c72fe730a4daab3ae30f930a5e968 dir: /sys/src/libc/386/387/tan.s/
TEXT tan(SB), $0 FMOVD a+0(FP), F0 FPTAN FMOVDP F0, F0 /* get rid of extra 1.0 */ RET