Hacker's Edge Game Guide: Tutorials/HEMon - The Hacker's Edge Monitor

HEMon - The Hacker's Edge Monitor
Feb. 3, 2018

At one point, the Hacker's Edge Monitor was provided as a ROM image within Hacker's Edge for initial development efforts, while useful, it has now been replaced by HackerOS. However, you can still load and run the HE Monitor from within Hacker's Edge, as it has been converted over into a regular binary program. This guide is going to go through how to use the monitor to help you either hack or debug programs on a host.

Hacker's Edge Monitor is based on the widely popular Woz Monitor, one of the co-founders of Apple Computer. You can find an off-site document about it here: The Apple Woz Monitor

Available operations

Examining memory (memory dump)

You can examine the contents of a single memory location by typing a single address followed by a Return.


004F: 0F

Note: The bold typed characters are what the user types. All other characters are responses from the Apple 1.

Now let us examine a block of memory from the last opened location to the next specified location.


0050: 00 01 02 03 04 05 06 07
0058: 08 09 0A

Note: 004F is still considered the most recently opened location.

We can also combine the previous two examples into one command:


0040: 0F
0050: 00 01 02 03 04 05 06 07
0058: 08 09 0A

Note: Only the first location of the block 4F is considered opened.

You can also examine several locations at once, with all addresses on one command line.

4F 52 56

004F: 0F
0052: 02
0056: 06

Note: 0056 is considered the most recently opened address.

Let's take this concept into the extremes and combine some block and single address examinations on one command line.

4F.52 56 58.5A

004F: 0F
0050: 00 01 02
0056: 06
0058: 08 09 0A

Note: By now you won't be surprised that 0058 is considered the most recently opened location.

Finally let's examine some successive blocks of memory. This can be handy if you want to examine a larger block of memory which will not fit on one monitor screen. Remember that there is no way to halt a large examine list other than hitting the RESET button!


004F: 0F
0050: 00 01 02

0053: 03 04 05

0056: 06 07
0058: 08 09 0A

Depositing memory (changing memory contents)

This is how to change a single memory location (provided it is RAM memory of course).


0030: FF

Note: FF is what location 0030 used to contain before the operation, from now on it contains A0. Location 0030 is now considered the most recently opened location.

Now we're going to deposit some more bytes in successive locations, starting from the last deposited location.

:A1 A2 A3 A4 A5

Note: Location 31 now contains A1, location 32 contains A2 and so on until location 35 which now contains A5.

Combining these two techniques will give us the next example.

30:A0 A1 A2 A3 A4 A5

0030: FF

Note: Location 0030 used to contain FF in this example.

Breaking up a long entry into multiple command lines is done like this:

30:A1 A2

0030: FF
:A2 A3

:A4 A5

Note: A colon in a command means "start depositing data from the most recently deposited location, or if none, then from the most recently opened location.

Now we're going to examine a piece of memory and then deposit some new data into it:


0030: A0 A1 A2 A3 A4 A5
:B0 B1 B2 B3 B4 B5

Note: New data deposited beginning at most recently opened location, which is 0030 in this example.

Running a program

To run a program at a specified address:

10F0 R

10F0: A9

Note the cursor is left immediately to the right of the displayed data; it is not returned to the next line. It's the program's responsibility to control the rest of the output.

From now on the user program is in control of the Apple 1. If the user program does not return to the Woz monitor (by jumping to address $FF1F) you'll have to press the RESET key to stop your program and return to the Woz Monitor.

You can also enter a program and run it all from the same command line. Please note that this only works for very short programs of course.

40: A9 0 20 EF FF 38 69 0 4C 40 0 R

40: FF