SpritesMind.Net

Also, I was confused for a bit because the assembly source emitted by the compiler (vbcc) didn't actually contain a clr instruction. It turns out the assembler (vasm) makes the substitution... which is why playing with compiler optimization levels (one of the first things I tried) didn't do anything...

Mask of Destiny wrote:OK, I found the problem.

Nice find by the way! I had actually heard about this issue once upon a time but of course couldn't put two and two together.

Like so
I've traced it to at least one function to clear a plane, since it always writes zero to clear it wants to use clr.l to do it.

I'm assuming I need to throw another keyword in there? Or just rewrite it in asm

I was thinking you could probably achieve the effect using h-ints to copy palettes at the appropriate times. You start with an all black palette, then when you hit the right scanline, switch to your color palette. Then when you hit the scanline you want on the bottom, switch back to all-black. You'd...

The code is very conservative and conventional too. Holding z80 for pad reads, using gemsdmastart/gemsdmaend before and after DMA. VRAM is still loaded in software, the DMA is only used for the palette and a copy of the sprite attribute table in RAM. There isn't even any use of sprites in this ROM s...

The fixed one works as intended in every emulator I throw it into including Blastem, but not from Megacart. If I was going to venture some sort of guess it probably has to do with bankswitching or something, but that doesn't explain a lot when commercial games by and large are compatible. Here it is...

I found the problem: a stray move #$2000,sr at the end of one of my VDP functions that I forgot to remove when I restructured my code to run in vblank! I had it set up to disable/enable interrupts before, when I couldn't guarantee an interrupt wouldn't happen, but that shouldn't happen now. The tric...

OK I stepped through it with IDA+GensIDA and I think I found the problem (which ironically, doesn't affect Gens in the slightest). This is something I REALLY should probably know, but: is it forbidden to mess with the SR inside an interrupt? (I mean, I don't know why you would, but is it "bad?") The...

Removing the pad initialization and inserting jumps to _gemsholdz80 and _gemsreleasez80 directly into the pad read code makes everything work (at least in Fusion). I doubt this would work on the real hardware though--right? edit: it leads to broken controls in Exodus, about like you'd predict. So wh...

Here's my pad code, copied & modified from various sources. The pad read functions don't anything with the bus because I'm using the GEMS functions (gemsholdz80/gemsreleasez80) for it: BUSREQ equ $A11100 xdef _pad_init xdef _read_pad_a xdef _read_pad_b ; int read_pad_a(void); ; bit0: up ; bit1: down...

It has something to do with the pad routines. I'm baffled

If I comment out any of the GEMS stuff the code just blows up elsewhere, so I must be handling a reset situation really incorrectly.

What needs to be done for reset?

Disabling interrupts has no effect, either. Still hangs on z80 busreq

Interrupts should be disabled on reset, right? as in, move.w #$2700,sr

Does most startup code not do this??

Here is a ROM. https://mega.nz/#!upRVzQzC!SdqjX3jIn4Wr8FTjfDv_Nk1TPDVHu_iyWJutgH1Rvlk It's a homebrew sound test for X-Men 2: Clone Wars. I have a youtube channel (https://www.youtube.com/user/DUSTINODELLOFFICIAL) where I do recordings of Genesis music from the real machine so it needs to work on th...