Trying Out ACK on MC6800 with emu6800

[zu2]

I'm porting ACK to the 8-bit MC6800 CPU for use with the emu6800 emulator. I'm using the cg code generator, but I'm having trouble adding the library, so runnable code isn't working yet. My current work is here: https://github.com/zu2/ack-6800
Any advice would be appreciated!

[zu2]

In the emu6800 environment (-me6800), support for stdin, stdout, and stderr has been added.
Currently, examples/hilo.c and paranoia.c are working.
On emu6800, no file system, so FILE I/O is unavailable.

$ ack -me6800 hilo.c
$ emu6800 6800 e6800.img /dev/null

Hi there! I'm written in C. Before we start, what is your name?
> zu2

Hello, zu2! See if you can guess my number.

> 50

Try a bit higher.

> 75

Try a bit lower.

> 67

You got it right in only 3 goes!

Would you like another go?
> 

[davidgiven]

Looks good so far! Is emu6800 small enough to be able to embed into the ACK source code? That way, it can be used to run the compiler tests.

What's the code quality like? I don't know a great deal about cg.

[zu2]

emu6800 source is at https://github.com/EtchedPixels/Fuzix-Compiler-Kit/tree/main/test.

Sizes:

  4853  20150 140642 6800.c
   306    913   7265 6800.h
   193    485   3491 emu6800.c
  5352  21548 151398 total

Performance matches typical MC6800 stack machine speed, which is decent for a first try.

cg/table pattern tweaks may improve speed by 10-20%.
Further improvements call for EM code reordering suited for MC6800, plus more reuse of register-held values.

I'll check if cg can support the latter.