Search found 70 matches

by DarkMoe
Wed Nov 01, 2017 10:44 am
Forum: General Stuff
Topic: Self-made misconceptions that you believed about games
Replies: 133
Views: 33962

Re: Self-made misconceptions that you believed about games

I didn't even know the game was a port from the arcade game, I was 6.
by DarkMoe
Wed Nov 01, 2017 9:05 am
Forum: General Stuff
Topic: Self-made misconceptions that you believed about games
Replies: 133
Views: 33962

Re: Self-made misconceptions that you believed about games

I always called Bison in SF2 (DOS), Mister Bison. Up to this day, I dont even know whats his name. Me being 6 years old, thought that since Guybrush Threepwood wanted to be a pirate, I needed to play the game taking bad decicions to be taken to jail, and then free Otis. Turns out, thats what you nee...
by DarkMoe
Tue Oct 18, 2016 1:41 pm
Forum: Other Retro Dev
Topic: Space Invaders arcade emulation
Replies: 10
Views: 8147

Re: Space Invaders arcade emulation

Ive used MAME for 17 years, and never used the debugger, shame on me.

I will check it out on the official site, thanks !
by DarkMoe
Tue Oct 18, 2016 1:04 pm
Forum: Other Retro Dev
Topic: Space Invaders arcade emulation
Replies: 10
Views: 8147

Re: Space Invaders arcade emulation

Ok fair enough. I will keep checking .. it's getting very difficult to debug and find an issue. I'm 80% certain that there's an issue with the flags. In some documents I read that the sign flag is set if there's a substract operation and clear if it's a sum. Others say that sign flag is set to the m...
by DarkMoe
Tue Oct 18, 2016 11:32 am
Forum: Other Retro Dev
Topic: Space Invaders arcade emulation
Replies: 10
Views: 8147

Re: Space Invaders arcade emulation

I think those comments are not quite right, since the first line of that function sets HL = 0x2010 I think every 0x10 bytes, theres a different object and the code is looping all of them, jumping to their respective handlers to handle logic, and then returning. For some reason, Im getting handler 00...
by DarkMoe
Tue Oct 18, 2016 7:25 am
Forum: Other Retro Dev
Topic: Space Invaders arcade emulation
Replies: 10
Views: 8147

Re: Space Invaders arcade emulation

I have those instructions correct, what is happening is this: 0262: 23 INC HL ; xx03 0263: 5E LD E,(HL) ; Get handler address LSB 0264: 23 INC HL ; xx04 0265: 56 LD D,(HL) ; Get handler address MSB When PC is 0x262, HL = 0x2072, gets incremented to 0x2073, which previously was loaded with memory val...
by DarkMoe
Tue Oct 18, 2016 5:28 am
Forum: Other Retro Dev
Topic: Space Invaders arcade emulation
Replies: 10
Views: 8147

Re: Space Invaders arcade emulation

026E: E9 JP (HL) ; Run object's code (will return to next line)

That's the line .. they were doing some sort of smart code there calling different functions while injecting manually the return vector to the stack.
by DarkMoe
Mon Oct 17, 2016 3:15 pm
Forum: Other Retro Dev
Topic: Space Invaders arcade emulation
Replies: 10
Views: 8147

Space Invaders arcade emulation

Hi ! I started for fun, a SI emulator, and got stuck at probably one stupid cpu, or flags bug. I have working inputs, the game boots perfectly, shift registers are emulated, but when all the aliens are shown, the game makes a jump HL() instruction to what was on the stack, which is 0000, and resets ...
by DarkMoe
Wed Sep 28, 2016 8:10 am
Forum: NESemdev
Topic: Getting right attribute tables with scrolling
Replies: 21
Views: 8230

Re: Getting right attribute tables with scrolling

You couldn't make it any clear.

You're awesome, thank you !
by DarkMoe
Wed Sep 28, 2016 7:00 am
Forum: NESemdev
Topic: Getting right attribute tables with scrolling
Replies: 21
Views: 8230

Re: Getting right attribute tables with scrolling

One more question though. If the PPU render a pixel for each PPU cycle, and cycle 0 is idle, it means that each pixel is rendered between cycles 1-256 on each scanline right ? How does that work when there's a fine X scroll ? if I just discard the 7 first pixels (if fine X is 7), then I'm missing th...
by DarkMoe
Tue Sep 27, 2016 10:50 am
Forum: NESemdev
Topic: Getting right attribute tables with scrolling
Replies: 21
Views: 8230

Re: Getting right attribute tables with scrolling

Excellent, thank you !
by DarkMoe
Tue Sep 27, 2016 6:35 am
Forum: NESemdev
Topic: Getting right attribute tables with scrolling
Replies: 21
Views: 8230

Re: Getting right attribute tables with scrolling

Followed all your advise, and got closer to the right behaviour. So what was happening, I was trying to fetch tiles using the fine x scroll value, in order to draw pixels directly, grabbing attributes the same way, but when I calculated the quadrant using the V register, I would always be off by 0-7...
by DarkMoe
Thu Sep 22, 2016 12:59 pm
Forum: NESemdev
Topic: Getting right attribute tables with scrolling
Replies: 21
Views: 8230

Re: Getting right attribute tables with scrolling

Narrowed it down to quadrant fetching. When there's fine X scroll involved, quadrant number and attributes data don't match. So, I guess I need to add that fine x scroll field to quadrant logic ? My current logic: if ((ppuV & 64) != 64) { if (((ppuV + ppuX) & 2) == 2) { quadrantPalette = (at...
by DarkMoe
Thu Sep 22, 2016 6:23 am
Forum: NESemdev
Topic: Super Mario Bros slides too much
Replies: 14
Views: 10788

Re: Super Mario Bros slides too much

Managed to fix it.

Turns out my shift left function, was setting carry flag from bit 7 of Accumulator, instead of using the operator passed to the function.

Figured it out implementing unofficial opcodes that use the ASL function.
by DarkMoe
Tue Sep 13, 2016 6:43 am
Forum: NESemdev
Topic: Getting right attribute tables with scrolling
Replies: 21
Views: 8230

Re: Getting right attribute tables with scrolling

Im going crazy. No matter what combination I use, when I get correct colours, the scrolling is glitched, and when scrolling works, I get those incorrect colors in some tiles. Any tips on what should I check ? I'm caching the first and second tiles on video cycles 328 and 336 of the previous line, an...