Multi Mode Demo Assembler Instructions


For details on a particular machine please click on one of the following:

1 Address Machine
2 Address Machine
5 Address Machine

General

The program simulates the five, two and one address machines, hereon referred to as
5AM, 2AM and 1AM respectively.

Layout

In the 1AM, the instruction pointer and the accumulator are shown in the top left
of the screen. The 2AM does not have an accumulator, while the 5AM has neither.
Below these is the instruction input area:

Input instructions here (NB - do not delete the memory cell locations 00: etc).
Input values in decimal. This is an 8-bit machine: values in the range -127 to +127
are valid. Negative numbers are encoded using one's complement. You should enter
HALT* as your final instruction.

When you have finished inputting your instructions, you can execute them by clicking
on the Step button (described below). A description of valid instructions for each
machine is also shown below.

The right of the screen is a representation of 256 memory cells. The contents of
each cell is represented in HEX. The opcode of the instruction currently being
executed is highlighted in yellow. A memory cell turns red when its contents are
changing.

There are two buttons below the instruction input area: Step and Reset Memory

Step:

Clicking Step executes the instruction current instruction. The opcode, encoded
in hex, for this instruction is highlighted in the memory in yellow.

Reset Memory:

Clicking this resets the entire contents of memory. You can reload your instruction
by clicking on the relevant one and pressing enter.

* not necessary if program will loop infinitely

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