
求解释!!一道小题而已,好了加分,急!!!
Showallthemicro-operationsforthefollowinginstruction:1.ISZX----incrementandskipifzero...
Show all the micro-operations for the following instruction:
1. ISZ X
---- increment and skip if zero
2. BSA X - Branch and save address
—Address of instruction following BSA is saved in X
—Execution continues from X+1 展开
1. ISZ X
---- increment and skip if zero
2. BSA X - Branch and save address
—Address of instruction following BSA is saved in X
—Execution continues from X+1 展开
2个回答
展开全部
1. ISZ X
Fetch cycle Execute cycle
t1: (PC) -> MAR t1: ad(MBR) -> MAR
t2: (MAR) ---> Memory t2: (MAR) ---> Memory
read ---> Memory read ---> Memory
t3: Memory ---> MBR t3: Memory ---> MBR
t4: (MBR) -> IR t4: (MBR)+1---> MBR
(PC) +1 -> PC if(ZF) =0 then (PC)+1 ->PC(测试可以与加1放在一起)
2. BSA X
Fetch cycle Execute cycle
t1: (PC) -> MAR t1: ad(MBR) -> MAR
t2: (MAR) ---> Memory (PC) -> MBR
read ---> Memory t2: (MAR) ---> Memory
t3: Memory ---> MBR write ---> Memory
t4: (MBR) -> IR t3: (MBR) ---> Memory
(PC) +1 -> PC t4: ad(MBR)--->PC
t5: (PC)+1 ->PC
Fetch cycle Execute cycle
t1: (PC) -> MAR t1: ad(MBR) -> MAR
t2: (MAR) ---> Memory t2: (MAR) ---> Memory
read ---> Memory read ---> Memory
t3: Memory ---> MBR t3: Memory ---> MBR
t4: (MBR) -> IR t4: (MBR)+1---> MBR
(PC) +1 -> PC if(ZF) =0 then (PC)+1 ->PC(测试可以与加1放在一起)
2. BSA X
Fetch cycle Execute cycle
t1: (PC) -> MAR t1: ad(MBR) -> MAR
t2: (MAR) ---> Memory (PC) -> MBR
read ---> Memory t2: (MAR) ---> Memory
t3: Memory ---> MBR write ---> Memory
t4: (MBR) -> IR t3: (MBR) ---> Memory
(PC) +1 -> PC t4: ad(MBR)--->PC
t5: (PC)+1 ->PC
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