ref: 5a2ad90bec85dbfd5c5f6bb1b0ff88a73cfe1911 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