ref: 8e9d2434e97fe6cf4b0d3e7f43e3e35d7ae1033f 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