Simulators
CPU Fetch–Decode–Execute
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RAM
Addr
Instruction
0
LOAD 15
1
ADD 27
2
HALT
Data Bus
fetchdecodeexecute
CPU
PC
0
Program Counter
ACC
0
Accumulator
Ready
Click Next Step to begin. The Program Counter (PC) starts at 0, pointing to the first instruction in RAM.
Register Key
PCProgram Counter: holds the address of the next instruction to fetch. Increments after each fetch.
ACCAccumulator: stores the result of every calculation performed by the ALU.