ref: 5a0c34e9fbe074df1d7090e31ab38a3a37675949 dir: /sys/src/libc/386/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