Search found 50 matches

by VEG
Thu Jan 10, 2019 1:26 am
Forum: NESemdev
Topic: TV System byte extension in iNES, NES 2.0, UNIF, NSF, NSFe
Replies: 20
Views: 15931

Re: TV System byte extension in iNES, NES 2.0, UNIF, NSF, NS

Oh, I see that NewRisingSun has already forced his own proposal to the NES 2.0 spec on the nesdev wiki. Congratulations. You've just made NES 2.0 worse. I was interested in the feature of the format, but I won't use this extension because of its drawbacks and poor backward compatibility.
by VEG
Thu Jan 10, 2019 1:13 am
Forum: NESemdev
Topic: TV System byte extension in iNES, NES 2.0, UNIF, NSF, NSFe
Replies: 20
Views: 15931

Re: TV System byte extension in iNES, NES 2.0, UNIF, NSF, NS

I said this already but most old emulators don't use any bits of the header to determine PAL vs NTSC . It is not true. I have checked at least a few emulators (Mesen, FCEUX), and they use this bit. "Old emulators" means not only emulators from 90's and 00's, it means all the emulators before 2019, ...
by VEG
Fri Dec 21, 2018 3:10 pm
Forum: NESemdev
Topic: TV System byte extension in iNES, NES 2.0, UNIF, NSF, NSFe
Replies: 20
Views: 15931

Re: TV System byte extension in iNES, NES 2.0, UNIF, NSF, NS

What's the benefit "Dendy with NTSC fallback"? If an emulator doesn't support Dendy for some reason, it will use NTSC. Also, if an old emulator (which isn't aware of changes in the spec) treats bit 0 to distinguish between NTSC and PAL ROMs (as spec says), it will use NTSC. We shouldn't change mean...
by VEG
Fri Dec 07, 2018 1:59 am
Forum: NESemdev
Topic: TV System byte extension in iNES, NES 2.0, UNIF, NSF, NSFe
Replies: 20
Views: 15931

Re: TV System byte extension in iNES, NES 2.0, UNIF, NSF, NS

In practice, the TV System byte is nonexistent for iNES 1. Rippers don't use it. Emulators don't use it. It was a late extension that never took hold. This byte is a part of the iNES spec for ages (since 2005 ). Mesen understands this byte, I guess that iNES also understands it, so emulators use it...
by VEG
Fri Dec 07, 2018 1:42 am
Forum: NESemdev
Topic: TV System byte extension in iNES, NES 2.0, UNIF, NSF, NSFe
Replies: 20
Views: 15931

Re: TV System byte extension in iNES, NES 2.0, UNIF, NSF, NS

Adding it to NES2.0 is adding it to iNES. These formats are different. For example, TV System byte is byte 9 for iNES and byte 12 for NES 2.0. This is about canonical headers. Given a specific PRG and CHR, what is the single correct 16-byte header that it should have. I believe that the iNES versio...
by VEG
Thu Dec 06, 2018 11:49 am
Forum: NESemdev
Topic: TV System byte extension in iNES, NES 2.0, UNIF, NSF, NSFe
Replies: 20
Views: 15931

Re: TV System byte extension in iNES, NES 2.0, UNIF, NSF, NS

The regular iNES header (first example) will fail a CRC check that expects the NES2.0 header. iNES header is still a valid one. You can't force everybody to use NES 2.0. A general set of ROMs consists of iNES files for 99%, and probably a few of NES 2.0 if any. It is stupid to expect that a ROM is ...
by VEG
Wed Nov 21, 2018 3:32 pm
Forum: NESemdev
Topic: TV System byte extension in iNES, NES 2.0, UNIF, NSF, NSFe
Replies: 20
Views: 15931

Re: TV System byte extension in iNES, NES 2.0, UNIF, NSF, NS

There is another proposal from the NewRisingSun: Byte 12: TV System 7654 3210 --------- .... ..TT ++- Frame timing 0: RP2C02 (NTSC) 1: RP2C07 (PAL licensed) 2: RP2C02 and RP2C07 (game self-adjusting or doesn't matter) 3: UMC 6527P (PAL with NTSC-like timing, also known as "Dendy" or "Micro Genius" m...
by VEG
Wed Nov 21, 2018 3:01 pm
Forum: NESemdev
Topic: NES 2.0 Additions Proposal
Replies: 224
Views: 133241

Re: NES 2.0 Additions Proposal

Also, there already was a now-deprecrated iNES replacement that had DWORD size specifiers, called UNIF . One of the reasons for its deprecation was lack of popularity. That problem will be even greater here: nobody is going to support a new format just for a few large-size homebrew and pirate ROMs,...
by VEG
Wed Nov 21, 2018 1:18 pm
Forum: NESemdev
Topic: NES 2.0 Additions Proposal
Replies: 224
Views: 133241

Re: NES 2.0 Additions Proposal

I have created a dedicated topic about it, with some additional details: viewtopic.php?f=3&t=18060
I hope that it will help to involve other people into the discussion.
by VEG
Wed Nov 21, 2018 1:11 pm
Forum: NESemdev
Topic: TV System byte extension in iNES, NES 2.0, UNIF, NSF, NSFe
Replies: 20
Views: 15931

TV System byte extension in iNES, NES 2.0, UNIF, NSF, NSFe

I had proposed to add Dendy support to the NES 2.0 format in 2016, here . Unfortunately, there was no active discussion. But now, in 2018, two important things happened. NSFe format now has Dendy support (in the regn chunk), and there is an another effort to add Dendy support to the NES 2.0 format, ...
by VEG
Mon Nov 05, 2018 12:12 am
Forum: NESemdev
Topic: NES 2.0 Additions Proposal
Replies: 224
Views: 133241

Re: NES 2.0 Additions Proposal

Yeah, let's make the messy NES 2.0 header format even more messier. More kludges, more hacks, more ugliness. For the sake of chaos and increasing of entropy. :twisted: Let's get back to the TV System byte, because it is the extension which would be really useful if added to the iNES, NES2.0 and UNIF...
by VEG
Sun Nov 04, 2018 11:33 pm
Forum: NESemdev
Topic: NES 2.0 Additions Proposal
Replies: 224
Views: 133241

Re: NES 2.0 Additions Proposal

Guys, don't be so short-sighted. Nothing prevents anybody from creation of a custom cartridge with 64+8KiB of PRG ROM, for example. I provide this amount of ROM as an example because I considered creation of such a mapper for some special purposes just a few months ago. And you argue with the least ...
by VEG
Sun Nov 04, 2018 4:16 pm
Forum: NESemdev
Topic: NES 2.0 Additions Proposal
Replies: 224
Views: 133241

Re: NES 2.0 Additions Proposal

2. No the exponent vastly increases the range of possible sizes. Please review what it actually does. I mentioned "if you want to keep compatibility with de facto NES 2.0 specification". It means that when different emulators (old and new ones) treat $F in different ways, it makes no sense to use s...
by VEG
Sun Nov 04, 2018 3:23 pm
Forum: NESemdev
Topic: NES 2.0 Additions Proposal
Replies: 224
Views: 133241

Re: NES 2.0 Additions Proposal

Also I'd like to discuss this part: Byte 9: Upper bits of ROM size 7 0 --------- CCCC PPPP C: 4 more CHR ROM size bits P: 4 more PRG ROM size bits If P/C has the value $F, header bytes $4/$5 changes meaning from number of 16 KiB/8 KiB PRG/CHR banks to the following floating-point-like format: 7 0 --...
by VEG
Sun Nov 04, 2018 2:38 pm
Forum: NESemdev
Topic: NES 2.0 Additions Proposal
Replies: 224
Views: 133241

Re: NES 2.0 Additions Proposal

According to VTxx hardware. Just FYI, there are a lot of famiclones which use something labeled VT02S. I have two of them in my collection: https://www.emu-land.net/forum/index.php?action=dlattach;topic=80654.0;attach=199679;image https://www.emu-land.net/forum/index.php?action=dlattach;topic=80654....