Simple FDE CPU Simulator

Program Builder

Add blocks to the program.

Add main instruction

Default values are added automatically. Change them beside each instruction.

Load preset

Loops are intentionally one level deep in this version. That keeps the focus on the FDE cycle rather than complex programming.

Run settings

Run speed

Program

The highlighted instruction is the one currently being fetched, decoded or executed.

CPU

Only one instruction is processed at a time.

FETCH
DECODE
EXECUTE
Ready
empty
empty
none
Press Next FDE Step to begin.

Output & Trace

OUTPUT instructions copy the current accumulator value here.

Recent CPU trace