Development tools

[Robb Bates]

OK, after a lot of frustrating false starts, I'm still trying to find a CP/M emulator that will work with VSC and DeZog debugging feature.  I've got the z88dk assembler installed and working to output a .bin file.  Which I can rename to .com and it runs.  But I'd like to have a CP/M emulator I can upload my file to and halt and debug.  MAME with RC2014 looked promising, but I can't seem to connect it to VSC.

Anyone know of something that might work?

Wayne, what do you use?

Robb

[Phillip Stevens]

On Saturday, 13 December 2025, Robb Bates wrote:

OK, after a lot of frustrating false starts, I'm still trying to find a CP/M emulator that will work with VSC and DeZog debugging feature.  I've got the z88dk assembler installed and working to output a .bin file.  Which I can rename to .com and it runs.  But I'd like to have a CP/M emulator I can upload my file to and halt and debug.  MAME with RC2014 looked promising, but I can't seem to connect it to VSC.

Anyone know of something that might work?

Hi Robb

There are two solutions I can suggest related to z88dk. I use one of them for a lot of different purposes, including debugging. The other one I don't use because its capability extends way beyond my needs. But both are related to z88dk-ticks. So let me start with the second one first, the one I know least about.

z88dk-gdb provides the debugger interface from ticks and connects to a gdbserver to permit line-by-line debugging of software in emulators or on real hardware. The gdbserver connects to a hardware debugger for the ZX Spectrum, and is used by many people are developing complex, timing sensitive, games.  z88dk-gdb also connects to VSCode and to CLion using the FUSE Emulator from Speccy Tools and CMake.

OK. So I don't use any of the above as my needs are more mundane. But, if you do use z88dk-gdb you can get support from the z88dk forum (probably Alex who built most of it). And if you get it going, please write it up and let us know. 

The simpler solution is to use a command line emulator and debugger tool called z88dk-ticks. It provides an instruction by instruction view of the registers and stack, and is fully symbolic so it is easy to use. The original function was to time code segments to understand what is fastest, and it is used to produce the benchmarks.

z88dk-ticks can emulate many machines and different CPUs (8080, 8085, gbz80, z80, z180, ez80, etc). If you feed it a COM file then it automatically assumes that it needs to emulate "CP/M 2.2". If you feed it a file (partially) named "rc2014" it assumes that you want to emulate a RC2014 Machine with ACIA serial interfaces, and it also supports calls to an emulated Am9511A APU and for an 8255 I/O device.

The CP/M emulation is not 100% complete and the BDOS file IO calls are emulated rather than being accurate. But for testing your program code (as opposed to testing BDOS code) it is sufficient.

z88dk-ticks will normally run in cycle timing mode, and usually a +test target build (a simple no I/O platform) is done and total ticks are calculated.

There is a debug mode where breakpoints can be entered and halted at. There is a trace mode, which produces a full text machine state, which can be useful for tracking where a program goes wrong too.

And for performance optimisation there is a hotspot mode where cycles at particular addresses or functions can be plotted. This is useful to identify where you can spend your effort to improve performance of your program. I have used that feature to profile the MSBASIC code for optimisation.

Hope that helps.

P.