The famous TinyBASIC interpreter is actually a nested interpreter: the bulk of the logic is implemented in a bytecode called TBIL.

There's a TBIL assembler implemented in TinyBASIC, but I wanted a modern one. So, I added a dialect to the fine assembler often called asl.

It doesn't quite match the syntax of what Tom Pittman's assembler took, and I haven't checked the output for correctness, but I did reach the milestone of getting a complete compiler run with no errors.

My code is on codeberg as is the listing file of my built version of the TinyBASIC interpreter

#retroComputing #mc6800 #tinyBASIC #BASIC

Grabbed a highlight from Sunday's #pinball hacking #stream where I explain what I'm working on and how it fits into my project to a chatter who dropped in.

A good overview if you're interested in my work reverse-engineering Data East's Time Machine so I can add my own enhancements to the code.
https://www.twitch.tv/gandalfdagreat/v/2489738146?sr=a

#reverseEngineering #mc6800 #disassembly #pinMAME #MAME #C #Livestream #twitch #hacking #retroComputing

Thank goodness for #docker it makes setting up software build environments almost effortless.

I'm getting spun up to build a simple simulator for Time Machine #pinball for PinMAME which will allow shooting shots with the keyboard by simulating the appropriate switch hits. The alternative is playing the switch matrix manually like a piano which isn't ideal.

This should allow me to get into the nitty-gritty of the code with PinMAME's debugger.

#ReverseEngineering #MAME #MC6800

Went off on a sidequest of learning the SLEIGH processor definition language for #ghidra to debug the #MC6800 support extension I'm using, only to now finally discover that it's working properly, I just have to clear and re-disassemble the relevant instructions after I set the register value the instruction is indexing off of.

Not what I'd call a waste of time, but I did get worried there was some hard-to-find bug that would kill my project. Fortunately it was actually just user error.

Another detour on the Time Machine #Pinball #disassembly project, I think the processor specification I've been using is incomplete. There are a lot of instances of indexed addressing being interpreted as an offset from the current address. This is making it hard to figure out where in RAM different pieces of data live without manually calculating the address.

Time to learn #Sleigh and patch the processor definition. Maybe the extension author will even accept a pull request.

#Ghidra #MC6800

"I was looking at the patent for the 6800 microprocessor and it includes a slush maker‽ The microprocessor floor plan diagram shows up in a slushy drink patent. Unbelievably, the patent office swapped diagrams between these two unrelated patents issued on Oct 19, 1976."

via Ken Shirriff
https://twitter.com/kenshirriff/status/1287138807863816193

#motorola #mc6800 #microprocessor #cpu #patent