Sharp MZ

Is that so? did you test it yourself and put the rear switch in the exact position for MZ700 mode? I don't have a real 800 so no, I did not test it myself. But I'm quite sure that it was tested in 700-mode - keyboard polling (done in the program itself by reading the matrix directly via the 8255, n...

Yes, there is no VBL interrupt on the 700. I expected the 800 to work in the same way in 700 mode, but apparently not. Tested on both emulator and a real 800. Keyboard is working in both cases, which it wouldn't unless running in 700 mode with correct memory map.

This is working on the 700 but always returns immediately on the 800 emulator in 700 mode.

It doesn't work on a real 800 either. Strange that keyboard is working but VBL not, when both is handled by the 8255. Oh well, I'll worry about this later

Speaking of z88dk - do you know how to specify the stack size? I'm running out of stack.

Well, in that case the code should wait "forever" when I wait for bit 7 to become 1? But it returns immediately regardless of which state I wait for.

Just tested this, and the problem is not the polarity. The code always returns immediately both when I wait for 0 and 1... Very strange. I'll ask Geir to test it on his real 800.

I guess it could be an emulator issue, but I find it strange if such an obvious bug has slipped through... I'm using this emulator: https://sourceforge.net/projects/mz800emu/ Edit: Had a (very) quick look at the emulator source, and it's possible that the polarity of the vbl signal has been reversed...

I have written a small program on the 700 that detects VBL by waiting for bit 7 on $e002 (8255 port C) to go low. This works well on the 700, but when I test this on an 800 emulator in 700-mode the code always returns immediately. How do I properly detect VBL on the 800?

Great Is it OK if I upload these to the sharpmz.org website?

Btw I've been looking for Headache for quite some time, I used to play this back in the mid 80's.