Search found 1717 matches

by 93143
Tue Mar 26, 2024 12:40 pm
Forum: SNESdev
Topic: Vortex
Replies: 5
Views: 433

Re: Vortex

The GSU-1 pinout supports 64 KB (a GSU-2 would support 128 KB). The Vortex cartridge only physically has 32 KB, probably for cost reasons. The framebuffer is 21 KB, and when I look at it in a debugger it doesn't move and takes multiple Vsyncs to clear (an operation which should take about 30% of a V...
by 93143
Sat Mar 23, 2024 7:27 pm
Forum: SNESdev
Topic: Vortex
Replies: 5
Views: 433

Re: Vortex

One of the things slowing down Vortex is the fact that it apparently doesn't double buffer on the GSU side. The only thing the GSU can do while waiting for the VRAM download to finish is clear the parts that have already gone. But since Vortex had only 32 KB of GPRAM, and the GSU-1 supports 64 KB, a...
by 93143
Thu Mar 14, 2024 5:29 pm
Forum: General Stuff
Topic: March 8
Replies: 9
Views: 567

Re: March 8

In both Eastern and Roman churches, men are expected to uncover their heads in church. No hats. I've decided to delete the rest of my response, on the grounds that it is not likely to be productive. I don't have the time to engage in a lengthy political or philosophical discussion here, and cursory ...
by 93143
Sat Mar 09, 2024 5:25 pm
Forum: SNESdev
Topic: SNES cracktros?
Replies: 5
Views: 503

Re: SNES cracktros?

Here's one from Bubsy 2, by Anthrox: https://forums.nesdev.org/viewtopic.php?p=292168#p292168 Augustus Blackheart posted it ten years ago, but his links are dead. No music, but the file is dated 1995 so I suspect it's pretty genuine. It uses mid-scanline raster effects, so older emulators don't run ...
by 93143
Wed Feb 28, 2024 3:56 am
Forum: SNESdev
Topic: snes assembly - beginnings, a few questions (wla-65816)
Replies: 104
Views: 8529

Re: snes assembly - beginnings, a few questions (wla-65816)

The point is, you might want to save P even if you've already clobbered N and Z.
by 93143
Wed Feb 28, 2024 12:07 am
Forum: SNESdev
Topic: snes assembly - beginnings, a few questions (wla-65816)
Replies: 104
Views: 8529

Re: snes assembly - beginnings, a few questions (wla-65816)

P doesn't just include flags. It also includes the register size, decimal mode, IRQ disable and emulation bits. Register size in particular is nasty if you clobber it without realizing.
by 93143
Thu Feb 22, 2024 9:22 pm
Forum: SNESdev
Topic: snes assembly - beginnings, a few questions (wla-65816)
Replies: 104
Views: 8529

Re: snes assembly - beginnings, a few questions (wla-65816)

And then you have "ExHiLoROM", which I think was only used by the chipless Star Ocean hack. $00-$3F:$8000-$FFFF, $40-$7D:$0000-$FFFF, $80-$BF:$8000-$FFFF and $C0-$FF:$0000-$FFFF are all unique with no mirroring. 95 Mbits. This is the biggest you can go without either using a bankswitching ...
by 93143
Wed Feb 21, 2024 4:15 pm
Forum: SNESdev
Topic: SPC700 is similar to Paula ?
Replies: 7
Views: 663

Re: SPC700 is similar to Paula ?

Do you mean Tales of Phantasia? Or was there a Symphonia demake for Amiga? Assuming you mean the SNES game: I wouldn't say the CPU load is "immense". It might be a noticeable hit in an action game to do it the way they did it, but a simple RPG intro sequence probably had room for much high...
by 93143
Wed Feb 21, 2024 3:27 pm
Forum: SNESdev
Topic: Trying to make the backmost sprites drop out first.
Replies: 42
Views: 2598

Re: Trying to make the backmost sprites drop out first.

Well, I ran some tests on real hardware, and it appears superfamicom.org was right, and the SNESDev wiki was wrong. It is the 32 lowest-index (highest-priority) sprites that get rendered, from the back (highest-index, lowest priority) frontwards until there's no more time to render slivers. My game ...
by 93143
Tue Feb 20, 2024 2:24 am
Forum: SNESdev
Topic: Trying to make the backmost sprites drop out first.
Replies: 42
Views: 2598

Re: Trying to make the backmost sprites drop out first.

I think you missed the point entirely. That's all irrelevant. No, I get your point. I'm taking another angle on your example to make my point, which is that compared with the PC Engine or even the Mega Drive, the SNES is powerful and flexible enough to affect the odds of needing this trick in the f...
by 93143
Tue Feb 20, 2024 2:24 am
Forum: SNESdev
Topic: Trying to make the backmost sprites drop out first.
Replies: 42
Views: 2598

Re: Trying to make the backmost sprites drop out first.

The way it works, if I'm not mistaken, is that the S-PPU scans OAM during each active scanline and collects the first 32 entries that intersect the subsequent line. Then during HBlank, it works backward through that list and renders up to 34 8-pixel tile slivers to a line buffer, which is then rende...
by 93143
Sun Feb 18, 2024 12:04 am
Forum: SNESdev
Topic: Trying to make the backmost sprites drop out first.
Replies: 42
Views: 2598

Re: Trying to make the backmost sprites drop out first.

I mean, there are work arounds. Keep in mind that the SNES has two 4bpp BG layers and one 2bpp layer in the most commonly-used mode, while the PC Engine only has one 4bpp layer (with no priority bit in the map format!?), and even the Mega Drive only has two 4bpp layers. This can provide some extra ...
by 93143
Tue Feb 13, 2024 4:05 pm
Forum: SNESdev
Topic: Two separate moving objects out of one background?
Replies: 23
Views: 1822

Re: Two separate moving objects out of one background?

Edit: Actually, I've just realised the mosaic effect at the end of each level there might give away a little of how the overall result was achieved, as the far centre background sections look like they might be a column of sprites that aren't affected by the mosaic effect and the rest is just on th...
by 93143
Mon Feb 12, 2024 8:43 pm
Forum: SNESdev
Topic: Two separate moving objects out of one background?
Replies: 23
Views: 1822

Re: Two separate moving objects out of one background?

Could I use that method to vertically scroll the multiple overlapping background layers at different speeds in something like the example above, where one or more layers should also be covering another where the splits would happen? Probably. The advantage over OPT would be that you could have non-...
by 93143
Sun Feb 11, 2024 5:01 am
Forum: SNESdev
Topic: What's the real cycle timing for LDA abs,x?
Replies: 8
Views: 758

Re: What's the real cycle timing for LDA abs,x?

From 65c816.txt: 12a Absolute,X -- a,x (BlT,LDY,STZ,ORA,AND,EOR,ADC,STA,LDA,CMP,SBC) (11 Op Codes) (3 bytes) (4,5 and 6 cycles) 1 1 1 1 1 PBR,PC Op code 1 2 1 1 0 1 PBR,PC+1 AAL 1 3 1 1 0 1 PBR,PC+2 AAH 1 (4) 3a 1 1 0 0 DBR,AAH,AAL+XL IO 1 4 1 1 1 0 DBR,AA+X Data Low 1/0 (1) 4a 1 1 1 0 DBR,AA+X+1 Da...