This game does not work well on a phone/tablet screen in portrait mode.

Main Memory (RAM)

Addr Op Code Operand
000LDA007
001ADD008
002SUB007
003BRP002
004STA009
005HLT000
006DAT000
007DAT001
008DAT002
009DATXXX

You will take the role of the Control Unit in this simple CPU (based on the LMC). You will work through the fetch-execute cycle to run this program which counts down from 3, storing the final value in memory and then it halts. Click here for the user guide.

ERROR : Unknown instruction!


M.A.R.

XXX

XXX



- select register to use bus -

P.C.R.

000


M.D.R.

XXX



- select register to use bus -

Accumulator

000


Reset button

Status

ZP

Arithmetic and Logic Unit

INPUT A = 000 and INPUT B = XXX


Control Unit

Cannot decode XXX

C.I.R.

XX