ref: 2a6e03968b9227e91b2df181fe8461d719395359 dir: /sys/src/libc/386/387/sqrt.s/
TEXT sqrt(SB), $0 FMOVD a+0(FP), F0 FTST WAIT FSTSW AX SAHF JLO bad FSQRT RET bad: FMOVDP F0, F0 CALL NaN(SB) RET