som v5 compiler


code optimisation

1.  jmp to ret -> ret
2.  jc to jmp.y -> jc.y

macro and (and (and x y) z)

3.  jc to mov v #0, jf.y v -> jc.y
4.  jc to mov v #0, jt.y v, $ -> jc.$

macro or

5.  mov v #1, jmp to jf.y,$ -> jmp.$
6.  mov v x, jmp to jf.y,$ -> jf.y x, jmp.$

7.  lop v, jmp to jf.y v, $ -> jinvlop.y, jmp.$
