ref: 0d2a10e4416dc7e9d94c8f37e4b0b27ddf2ccc73 dir: /sys/src/ape/lib/ap/386/tas.s/
TEXT tas(SB),$0 MOVL $0xdeadead,AX MOVL l+0(FP),BX XCHGL AX,(BX) RET