Proof: Byte 3 Stays the Same 21
Let's prove the following theorem:
if the following are true:
- instruction #9 is
jump imm=(-6) - the PC at time 21 = 9
- value of cell 3 at time 21 = 3
then value of cell 3 at time 22 = 3
Instructions
| Memory Cells |
|---|
| Program Counter | Time |
|---|---|
| 0 | 0 |
LW Computer Simulator
Proof:
Given
| 1 | instruction #9 is jump imm=(-6) |
|---|---|
| 2 | the PC at time 21 = 9 |
| 3 | value of cell 3 at time 21 = 3 |
| # | Claim | Reason |
|---|---|---|
| 1 | value of cell 3 at time (21 + 1) = value of cell 3 at time 21 | if instruction #9 is jump imm=(-6) and the PC at time 21 = 9, then value of cell 3 at time (21 + 1) = value of cell 3 at time 21 |
| 2 | 21 + 1 = 22 | 21 + 1 = 22 |
| 3 | value of cell 3 at time (21 + 1) = value of cell 3 at time 22 | if 21 + 1 = 22, then value of cell 3 at time (21 + 1) = value of cell 3 at time 22 |
| 4 | value of cell 3 at time 22 = value of cell 3 at time 21 | if value of cell 3 at time (21 + 1) = value of cell 3 at time 22 and value of cell 3 at time (21 + 1) = value of cell 3 at time 21, then value of cell 3 at time 22 = value of cell 3 at time 21 |
| 5 | value of cell 3 at time 22 = 3 | if value of cell 3 at time 22 = value of cell 3 at time 21 and value of cell 3 at time 21 = 3, then value of cell 3 at time 22 = 3 |
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