ref: 1f3f4cd06bccbaa68e34a7e5d5008c8e788e5db2 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