ref: 8fdf22d5fb5dca8b0acb1cbfccca1eda33b7d39f dir: /sys/src/libc/386/387/sin.s/
TEXT sin(SB), $0 FMOVD a+0(FP), F0 FSIN RET TEXT cos(SB), $0 FMOVD a+0(FP), F0 FCOS RET