simulator · A1.1.5
The fetch-decode-execute cycle
Every micro-step below is one numbered step from the exam answer: watch which register changes and which bus carries it. Read the theory
The hello-world of the FDE cycle: load, add, store, output.
CPU
fetchdecodeexecutecycle 0
Control Unit
decodes the IR, sequences signals
ALU
add, subtract, compare → AC
PC
0
MAR
·
MDR
·
IR
·
AC
0
RAM
- 0LDA firstpc
- 1ADD second
- 2STA result
- 3OUT
- 4HLT
- 54
- 63
- 70