ref: 0d2a10e4416dc7e9d94c8f37e4b0b27ddf2ccc73 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