I’d like to learn how to program in Assembler. I’ve done a bit of assembly before (during my A-Level Computing course) but that was very definitely a simplified ‘pseudo-assembler’. I’ve borrowed my Dad’s old Z80 Assembler reference manual, and that seems quite interesting so if possible I’d like to have a go with Z80 assembler.
However, I don’t have a Z80 processor to hand, and would like to do it on my PC (I have windows or linux so either is good). I’ve found various assemblers around on the internet, but I’m not particularly interested in assembling down to a hex file, I want to just be able to assemble it to something that some kind of simulator on the PC can run. Preferably this simulator would show me the contents of all the registers, memory locations etc, and let me step through instructions. I’ve found a few bits of software that suggest they might do this – but they either refuse to compile, or don’t seem to work properly. Has anyone got any suggestions? If there are good simulator/IDE things available for another type of assembler then I could try that instead (assuming there is a good online reference manual available).
Write one. You’re best off picking a nice, simple instruction set (Z80 should be perfect). I remember doing this as a first-year undergraduate exercise – I think we wrote the simulator in C++ and simulated 6800 assembly, but really any language/instruction set will do.
The idea of ‘learning assembly language’ these days is to get the idea of how computers work at the lowest level, only a select few (compiler writers, etc.) have any real reason to actually be writing assembly code these days. Modern processors are stuffed full of features designed to be used by compilers to help optimise code for speed/concurrent execution/power consumption/etc., and trying to write assembly by hand for a modern processor would be a nightmare.
Don’t fret about getting your application production-ready unless you want to – in all likelihood the bits of software you’ve found so far were written by people exactly like you who wanted to figure out how assembly works and wrote their own simulator, then realised how much work would be involved in getting it ‘production ready’ so the general public could use it.