I wrote a fairly simple assembler (no macros) as part of the C02 project. Right now it reads and writes to files, but it should be simple enough to adapt it to use text and binary blobs. The files are a02.c and a02.h at https://github.com/RevCurtisP/C02.

It doesn'y look like this has been mentioned. Windows 10 doesn't natively support .hlp files. It would be nice to have the docs recompiled to a .chm file.

I like the idea of emulating VIAs, since nearly every physiical 6502 based system used some variation of them.

For mine, I simply have "magic" addresses. For example, I have an address that returns 0 or 1 if a key is ready, and another that returns the key value. Similarly, if I write to an address, a character appears on the display.
I would have it return 0 or 255, that way it can be tested with the BIT ...

Csn you please post some example code?

The PCB edge connector just duplicates all the signals coming from the cable. Perhaps it was originally intended for some sort of daisy chaining.

There are hacks online to using it for duplication.

I fixed a bug in the parsing of escape sequences in strings (dumb mistake, but took me a while to find it).

But more importantly I made two changes to expression parsing and compilation: Expressions may be used as indexes in any subscripted array references within expressions, and function calls ...

After a few months hiatus, I've started working on C02. I fixes a bug with break & continue in do/while loops, add a tag for strings to printf() in library stdiox.

I also added a new library memio, which mimics file i/o functions, but reads and writes directly to memory, for use with machines and ...

I've been running py65mon in a command window in Windows 10 and don't recall seeing any of these problems. Which version of Python are you running?

PHA/PLA don't affect the status register at all flag, so maybe something like this: for example

BTW: This may be a dumb question, but why is the video always wider than tall? For example, 320x200 seems to be common. Why not 320x320? This would be a 25KW frame-buffer which is still reasonable, and you would get square pixels that would simplify the programming (moving up or down one pixel ...

It always helps if you post all your code, as well.

This looks suspiciously similar to Batari Basic.

Put that in a Mimic System's Spartan and you'll have three computers in one.

Is this one correct?
do (c = getchr(); putchr(c); while (c<>13)
It looks to the untrained eye like there's an unmatched parenthesis following `do` This should have been
do {c = getchr(); putchr(c);} while (c<>13) I'll fix it.

I see that:
i:+
..is a condition for "i is positive". It might be ...