Blargg CPU test - NESdev BBS

Blargg CPU test
by kevtris on 2010-10-15 (#68677)

I thought for fun I'd finish up implementing all the instructions into my NES CPU by adding the last 4 or 5 that I didn't add before.

Anyways, 2 opcodes still don't work properly and I am not sure why. These are 9Ch and 9Eh. Both are "undefined" opcodes which do different things depending on which source you check. I know that it doesn't really matter *too* much if they don't work right but I'd like to have them function properly.

Other than that, everything else is Great Success(tm).

Blargg, can you make a 256K version of that integrated test ROM some time like the others? The current one is short a PRG bank (15 instead of 16) so I cannot run it. Unless duplicating the last bank or something will fix it. Thanks in advance if ya do.

by albailey on 2010-10-15 (#68690)

Which of the test roms are you using.

He posted version 5 in this thread
http://nesdev.com/bbs/viewtopic.php?t=3831

I also cannot figure out how to get 9C and 9E working. In the above post, blargg alluded that he would likely just remove those opcodes altogether.

edit- the reason I ask which version is that version 5 is 265K in size, and the header indicates 16 PRG and 1 CHR bank which should satify the problem of 15 banks you mentioned.

Al

by blargg on 2010-10-15 (#68704)

When I was writing those tests, there were some instructions which seemed to depend on things I couldn't figure out, and I removed them. These seem to be the same way. Doesn't seem worth spending any time on, along with all the other really obscure things that aren't currently worth the time it takes to figure them out.

And yeah, just duplicate the last 16K PRG bank and increase the PRG count; it knows how many banks there are and won't go past the last test. Future releases should be more standard, as I've finally gotten it through my head that iNES isn't a "build-your-own-board" format, rather a "specify-something-that-can-exist" format. So I'll be using NROM for 32K PRG/8K CHR tests, UNROM for 32K PRG/0K CHR, and MMC1 with a power-of-two PRG size for the multi tests. Hopefully that will be compliant with everything.

by kevtris on 2010-10-19 (#68896)

blargg wrote:
When I was writing those tests, there were some instructions which seemed to depend on things I couldn't figure out, and I removed them. These seem to be the same way. Doesn't seem worth spending any time on, along with all the other really obscure things that aren't currently worth the time it takes to figure them out.

Thanks for the info, I will duplicate the last bank and give it a shot. I was just unsure if that would confuse it or if I had to duplicate the first bank. thanks!