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Nice. Can't be more perfect. :)

Anyway... mm... a system after Chip-8? Whichever one, actually.

Though... since you got Chip-8 working, maybe try Gameboy next. Gameboy is quite a piece of work.
 

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Oh yeah, and a new way to implement the drawing opcode (faster than pixel-by-pixel), I think would be... XOR a complete line of bits into VRAM. Namely... you have 8 bits (1 byte) for the first scanline of the sprite, you just XOR that into the video memory.

Then check that memory section after XORing and if it's not equal to the original sprite data of the scanline (8 bits long, ya), then something was erased, and collision flag needs to be set.

Just another tip. I get the feeling people are doing it pixel by pixel and checking for which bit is erased... which might be quite tedious. ;)
 

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Try switching your left scroll and right scroll functions.

The HP48 flags might not do anything... since I can get the games you mentioned to work fine without relying on that flag.
 

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Mmmm... I've seen that kind of output at some point... but I can't remember what caused it. Maybe you're indeed scrolling too much. Should be about 4 pixels per scroll? (2 in Chip-8 Hybrid mode)

So far, I haven't seen anything but tests making use of the Chip-8 hybrid features, or the HP48 flags and instructions.
 

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lol Gameboy is much too hard? I think it's just because of the way they documented it. I don't remember where but I got a much better way to document the opcodes of the CPU...

Maybe I'll take my time to write some docs soon...
 

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You read about it in the Chip-8 thread. Shendo was having the same problem. :p

Look back at your subtraction opcode. The flag should be set also when the result of the subtraction is 0, not just when the result is less than 0. VF is actually a carry AND zero flag, not just a carry flag.

Cowgod forgot to put that in his document. Or maybe he didn't know about that himself.
 

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And thus born the 100th or so Chip-8 emu. :lol:

I think you really should work on Gameboy. There are very few emus for it.

Actually, now that I think about it, handheld consoles get very few emus.
 
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