Search found 433 matches
- Fri May 25, 2018 6:43 pm
- Forum: SNESdev
- Topic: bsnes-mcfly: The v073 and bsnes-classic killer
- Replies: 179
- Views: 139975
Re: Is AWJ still in the scene? Regarding bsnes-classic
Yep, I just got his private message, too. AWJ has spoken: his project is still alive, and he wants me to rename my project. I replied to him that it would be really nice if he could either update bsnes-classic's manifest format to BML, or retire manifests and exclusively use heuristics. I'll still ...
- Fri May 25, 2018 3:45 am
- Forum: Newbie Help Center
- Topic: Trying ROM Disassembly & getting lots of Invalid Opcodes
- Replies: 9
- Views: 7595
Re: Trying ROM Disassembly & getting lots of Invalid Opcodes
There must be some "manual" for 6502 in Japanese that shows how to do the "read data past the JSR with stack manipulations" as for some reason a lot of Japanese games I look at do it. so you get JSR somePlace .word Address, Address, Address, Address code On the 6502, this techni...
- Mon Oct 23, 2017 6:28 pm
- Forum: SNESdev
- Topic: Super Game Boy enhanced games hotpatch the SGB firmware?
- Replies: 9
- Views: 8766
Re: Super Game Boy enhanced games hotpatch the SGB firmware?
it's also done automatically by SGBv1/SGBv2/SGB2v1 (ie. games would need to apply the patch themselves only for SGBv0). It's actually only SGBv2 and SGB2 that contain the patch (at offset $3F400 in the ROM) SGBv1 doesn't have it. SOU_TRN Patch this patch disables H+V IRQ during SOU_TRN, unknown whe...
- Sun Oct 22, 2017 3:36 pm
- Forum: SNESdev
- Topic: Super Game Boy enhanced games hotpatch the SGB firmware?
- Replies: 9
- Views: 8766
Super Game Boy enhanced games hotpatch the SGB firmware?
I've been looking at Game Boy stuff lately, and I noticed that most Super Game Boy-enhanced games send one or two standard sequences of DATA_SND command packets (the SGB command to transfer up to 11 bytes to an arbitrary SNES address) at startup when they detect they are running on a SGB. The payloa...
- Thu Oct 05, 2017 6:16 am
- Forum: NESdev
- Topic: Drawing text in CHR-RAM
- Replies: 10
- Views: 5725
Re: Drawing text in CHR-RAM
Most of the time the original japanese version has fixed width character, but often a width of 8 is insufficient for kanjis and a width of 16 is too much, so they used a value in-between and pain the characters in VRAM on the fly. Also, most systems lacks enough WRAM to store all kanjis used in a g...
- Sun Sep 03, 2017 11:40 pm
- Forum: SNESdev
- Topic: upd7725 overflow (attn: byuu)
- Replies: 24
- Views: 14382
Re: upd7725 overflow (attn: byuu)
The 7720 and 7725 appear to be pin-compatible, except that the EPROM versions of both require power on pin 1. I wonder if you could put a programmed 7720 onto a suitable SNES cartridge for software testing, rather than have to use an Arduino or something.
- Sun Sep 03, 2017 9:42 pm
- Forum: SNESdev
- Topic: upd7725 overflow (attn: byuu)
- Replies: 24
- Views: 14382
Re: upd7725 overflow (attn: byuu)
Well, I wrote a program that should allow you to test any sequence of ALU operations you want, if someone wants to figure out how to assemble, burn and test it (don't forget the screwy bit order the '7720 needs for its program ROM) The command protocol is heavily based on the DSP-1, including the ne...
- Sun Sep 03, 2017 7:34 pm
- Forum: Newbie Help Center
- Topic: Attribute / Tile
- Replies: 19
- Views: 8868
Re: Attribute / Tile
Yeah, I figured out a different way to calculate it, but wanted to make note of this seeming wrong, for any future readers :-) One thing to keep in mind is that unless your game uses 4x4 metatiles and only scrolls along one axis at a time Well, I am using 4x4 metatiles. But doing free all-direction...
- Sun Sep 03, 2017 5:13 pm
- Forum: Newbie Help Center
- Topic: Attribute / Tile
- Replies: 19
- Views: 8868
Re: Attribute / Tile
One thing to keep in mind is that unless your game uses 4x4 metatiles and only scrolls along one axis at a time, you're going to have to read-modify-write attribute table bytes in order to update individual 2x2 tile cells. Since accessing PPU memory this way is extremely inefficient, you'll probably...
- Sun Sep 03, 2017 4:16 pm
- Forum: SNESdev
- Topic: upd7725 overflow (attn: byuu)
- Replies: 24
- Views: 14382
Re: upd7725 overflow (attn: byuu)
Just noticed the question about multiply overflow in byuu's forum thread. 0x8000 * 0x8000 -> int31 is considered an "overflow" because the sign of the result is wrong. Multiplying two negative numbers should produce a positive result, but int31(0x40000000) is negative.
- Sun Sep 03, 2017 2:36 pm
- Forum: NESemdev
- Topic: Advices on implementing mixed switchable and fixed PRG banks
- Replies: 6
- Views: 5147
Re: Advices on implementing mixed switchable and fixed PRG b
Hi, my emulator is currently only supporting mapper 0, so the PRG-ROM is just a 32 kB chunk that gets loaded at ROM load and that's it. So mappers that switch entire 32 kB PRG banks are trivial, but for mapper 2-UNROM, for example, that uses one switchable 16 kB bank and another one fixed, I've tho...
- Sun Sep 03, 2017 2:15 pm
- Forum: SNESdev
- Topic: upd7725 overflow (attn: byuu)
- Replies: 24
- Views: 14382
Re: upd7725 overflow (attn: byuu)
PS. I think my implemention might have opposite S1 values (ie. 0=positive vs 1=positive), this works as long as SGN opcode is processing S1 accordingly. The manual is clear that the chip can distinguish between two overflows in the same direction (OV1 flag remains set) and two overflows in opposite...
- Sat Sep 02, 2017 7:04 pm
- Forum: NESemdev
- Topic: VRC2/4 test program WIP
- Replies: 21
- Views: 33191
Re: VRC2/4 test program WIP
Attached is my modification of Nintendulator's Mapper DLL source file that passes all of AWJ's submapper identification tests. The only complaint the ROM still has is that the pseudo-scanline IRQ is "late". It looks like you were working from an outdated version of Quietust's sources. Rec...
- Sat Sep 02, 2017 8:14 am
- Forum: NESemdev
- Topic: VRC2/4 test program WIP
- Replies: 21
- Views: 33191
Re: VRC2/4 test program WIP
.byte $02, $01, Result::yes, Result::vrc4 ; mapper 23 sub 3 That should be Result::vrc2. Thanks a lot for bumping this thread; I'm embarrassed to admit I'd totally forgotten about this little project :oops: Checking my local copy of the source against the attached WIP, it seems I'd already fixed th...
- Fri Sep 01, 2017 6:46 pm
- Forum: NESdev
- Topic: SimCity prototype found!
- Replies: 79
- Views: 47645
Re: SimCity prototype found!
The SNES has 128KB of onboard RAM, so the entire cartridge RAM can be dedicated to save data. On the NES it's most likely that one of the two cartridge RAMs is work RAM and the other is save data, just like all the Koei games. ideally yeah. but if I ever have the option to make a cart out of this, I...