Plan 9 from Bell Labs’s /usr/web/sources/contrib/rsc/linuxemu/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