Anders Hesselbom

The built-in machine code monitor

2010-05-27

The Commodore 128 features a few built in applications and one Easter egg. The egg is a list of the engineers that built the machine, with the word “hardware” intentionally misspelled as “herdware” after 8-bit computer designer Bil Herd. To reveal the egg, type this:

SYS 32800,123,45,6

The Commodore 128 tries to boot from floppy at startup. To start the CP/M operating system, you would make sure to have the boot disk inserted at startup. If you want to start the system without resetting the machine, you could just type BOOT and press enter. BOOT tries to load data from the floppy without generating an error if it fails.

The built in machine code monitor gives you the ability to view memory content (ROM and RAM) in binary format or as instructions. You choose the format that is best suited for the type of data you want to view. Also, the monitor lets you type in instructions in the RAM.

You enter the monitor by typing MONITOR.

While in the monitor, type M to dump 96 bytes on the screen. Type M again to dump the next 96 bytes. You can also specify a desired starting address after M.

By typing D, a disassembled version of the machine code is displayed. Just as with M, you can specify a starting address.

Type X to leave the monitor.

Categories: Geeky

Tags: C128