nesdev.org

I think this is one of the two docs being referred to, see page 140.

http://bitsavers.informatik.uni-stuttga ... a_Book.pdf

Ok, self posting, but it does appear that I might have resolved this. If what I've got is correct it wasn't in fact the MEMPTR but the flags on the non indirect BIT instruction. My implementation followed the comments inside of the Undocumentd Z80 PDF which states: SF flag Set if n = 7 and tested bi...

Hi all, I wondered if anyone else had worked on a Z80/SMS emulator that passes zexall sms? I've managed to implement all the instructions and have a full pass on zexdoc (using the sdsc version as I do not currently implement the vdp). Running zexall shows passes on all except this one: bit n,<b,c,d,...

Concerning Blargg's timing tests, is it sufficient for the emulated CPU to wait the instruction length in T-cycles and then carry out the instruction atomically, or does it need to process instructions incrementally, one microcode at a time. There are some instructions that perform multiple reads a...

zerowalker wrote:And also, isn't it "high nibble is above 0x09" that's what i did as the table said so, which i think is equal to A > 0x90.

That would adjust the accumulator for values 91..99 as well, you would need to mask A (A & 0xF0) to use that as a comparison.

adam_smasher wrote:This might be a known bug in the game.

That's exactly what I'm seeing. Thanks for the link.

I'll stop looking for that bug in my Emu now.

Edit: Yup, if I go to a screen without Octoroks and do the same the intro is fine.

Apologies, filename is "Legend of Zelda, The - Link's Awakening (U) (V1.2) [!].gb", testing on my DMG emulator.

MD5: 69 d6 43 bf 4e 37 b3 c1 33 51 85 17 33 8b 6a 1c
SHA1: 5a b6 3d ef 95 87 28 93 35 71 c3 b4 f6 af 54 db 14 f3 f8 b2

I've been trying to resolve what I believed was a bug in my emulator but now I'm not so sure. I can reproduce it when selecting Save & Quit after dying, it returns to the intro animation but the sprites are corrupted using enemy sprites in place of the lightning etc. I've been able to consistent...

Oooh, new documentation.

Thanks for pointing that out, a quick look shows I have come across it before but forgot about it. Excellent resource.

Forgive the self post but I thought I'd follow up. I wonder is this another of those GameBoy issues where a few people have worked it out but it's not documented anywhere? I have consulted some other emulators and the behaviour seems to be that if interrupts are disabled and there is a pending inter...

Hi all, I'm hoping someone can give me a steer on implementing the HALT bug? I have had a few attempts in my emulator at implementing this but based on the results of a halt_bug.gb test rom I found at https://github.com/retrio/gb-test-roms I cannot get it passing. The closest I have got has the resu...

Apologies, should have been clearer.

I meant that cart ram when it has it and the MBC is a battery type.

I'll save it all out. Thanks.

Hi all,

Hopefully a simple question, when a mapper specifies that it has a battery backup should I save the state of the entire RAM out when my emulator exits or is there a range of memory that is specifically battery backed?

Cheers

The LD r,r' instructions do not set any flags.

I can only assume that these are being reported as failures due to a problem with some of the other instructions that the test code is using to verify the result.

This is from my (C#) GB emu, originally based on code posted by Blarrg and passes his GB cpu tests. private void Daa() { int a = _regs.A; if (!_regs.F.HasFlag(Flags.N)) { if (_regs.F.HasFlag(Flags.H) || (a & 0xF) > 9) a += 0x06; if (_regs.F.HasFlag(Flags.C) || a > 0x9F) a += 0x60; } else { if (_...