This computer demonstrates the workings of a simple computer. It has 100 memory locations in a 10 by 10 grid with addresses 0 to 99 numbered from the top left row by row. The computer has a program counter which is stored in register PC and an accumulator AX. You may single step through a program or run it in one sequence. You may also specify the delay speed to observe the actions of the machine. Memory cells that are referenced become green for one instruction, those that are changed become red. This demonstrates some of the aspects of machine and assembly language programming.
This simulator was originally written as a Java applet by Barry G. Adams of Laurentian University. Several features were added by Curt Hill of Valley City State University. Cay Horstmann reimplemented the simulator in JavaScript.
The following table shows the instructions that are available for this computer:
| Mnemonic | Code (1st word) | Code (2nd word) | Description |
|---|---|---|---|
| STORE | 160 | n | Store the contents of AX in memory location n |
| LOAD | 161 | n | Load AX with the contents of location n |
| ADDI | 44 | n | Add n to AX (add immediate) |
| SUBI | 45 | n | Subtract n from AX (subtract immediate) |
| ADD | 50 | n | Add the contents of location n to AX |
| SUB | 51 | n | Subtract the contents of location n from AX |
| MUL | 52 | n | Multiply the contents AX by the contents of location n |
| DIV | 53 | n | Divide the contents of AX by the contents of location n |
| JPOS | 127 | n | Jump to the instruction in location n if AX > 0 |
| JZERO | 128 | n | Jump to the instruction in location n if AX = 0 |
| HALT | 0 | Halt the execution |