Gigatron Hackers

You can't post into someone else's Contrib without their permission, so the only place left is your own.

This is excellent, especially the second version!

You've found a couple of issues here: From SYS-functions.txt: Naming ------ The naming convention is: SYS_<CamelCase>[_v<V>]_<N> With <N> the maximum number of clocks or cycles (not ticks!) the function will need, counted from NEXT to NEXT. This duration <N> must be passed to the 'SYS' vCPU instruct...

Welcome to the forums, you sure can!
https://github.com/kervinck/gigatron-rom/pulls

Looks and plays great!

That's correct Xpp is a post increment of X, the increment happens after the operation

Emulator: Various HW/SW links:

Yes that's correct.

Documentation is here: You can also single step through ROM source code in my emulator package and watch exactly how the native instruction works.

It's a SYS function/call, SYS functions are called from vCPU code like this: LDWI 0xFFFF ; 4 pixels STW 0x24 LDWI 0xFFFF STW 0x26 LDWI 0x0800 ; pixel address STW 0x28 LDWI 0x04d4 ; SYS_Draw4_30 STW 0x22 SYS 30 loop BRA loop

I disasembled Your program. You and at67 used very smart trick: if color is biger that 63 then is black. Congratulations! What I did was pretty simple and somewhat sneaky: 1) Only one loop with no comparisons. 2) You can treat screen memory as one complete non-fragmented segment, i.e. write pixels ...