给定下列中缀式分别写出等价的后缀式和四元式运算符优先级按常规理解。1 a＋bca＋b－d2 x+y≤z∨a03 x＋y≤0∨ x―y24 a= bc―a a

(1) 后缀式：abc*+ab+/d- 四元式： (1) mul b c t1 (2) add a t1 t2 (3) div t2 a b (4) sub t3 d b

(2) 后缀式：xy+z≤a0>∨ 四元式： (1) add x y t1 (2) cmp t1 z t2 (3) jle t2 a L1 (4) mov 1 t3 (5) jmp L2 (6) L1: mov 0 t3 (7) L2: or t3 a t4

(3) 后缀式：xy+0≤xy-2>∨ 四元式： (1) add x y t1 (2) cmp t1 0 t2 (3) jle t2 L1 (4) sub x y t3 (5) cmp t3 2 t4 (6) jgt t4 L2 (7) mov 1 t5 (8) jmp L3 (9) L1: mov 0 t5 (10) L2: or t2 t5 t6 (11) L3:

(4) 后缀式：bca-a:=a 四元式： (1) mul b c t1 (2) sub t1 a t2 (3) mul t2 a t3 (4) mov t3