MonST Keyboard Shortcuts


MonST is part of the Hisoft Devpac IDE on the Atari ST. MonAM is the Amiga equivalent. It is a solid debugger for 68000 assembly language programmers. Although Devpac 3 supported newer CPUs (68020, 68030) and is necessary for developing code on newer machines like the Atari TT and Falcon, Devpac 2 was used for many years on the Atari ST and STE.

MonST can be used as a standalone debugger. It is very small (24kB) making it handy for low memory machines, single sided disks and even cartridge based installations although I have never seen it in a cartridge myself. Hisoft never made a cartridge version as far as I know but that would be a very useful tool indeed.


With PC keyboard layouts and Atari ST emulators (Steem, SainT and Hatari) I though it would be good to summarise the keyboard shortcuts for this great program.

Command Meaning
TabCycle through Windows
CTRL+LLoad executable
CTRL+YTrace or "single step" as it's called in modern IDEs.
RRun with slow options
DSet current drive/directory
Alt+RRegister=value, e.g. d0=0, pc=pc-6
Alt+EEdit memory, e.g. add in 4E71 (nop)
Alt+LLock the memory or disassembly window to a register e.g. ALT+L and enter A7 to lock it to the stack
MSet window start address
URun until PC=, e.g. PC=31D00
CTRL+BSet breakpoint (Breakpoints are automatically cleared when reached)
CTRL+OSwitch between med + low res
SSave binary (filename then start address and length have to be typed in)
GSearch for B/W/T/L/I (byte, word, text, longword, instruction)
e.g. W 4E71, T TFMX etc.
CTRL+CExit process


1. Debug symbols are shown in MonST if the executable has been built with extended debug information.
2. Sometimes the second label is shown if 2 labels are at the same address in the code.
    jmp start
In this case label2: will be shown.
3. Loading an executable is subject to GEMDOS memory allocation. I don't think executables can be saved from MonST but it can give the programmer enough information to fix bugs in the source or information to go on after disassembling the program with Easy Rider 4 for example.

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