Search found 2487 matches

by Chilly Willy
Fri Nov 17, 2017 6:20 pm
Forum: Megadrive/Genesis
Topic: Sprite List Code Messed Up
Replies: 22
Views: 419

Re: Sprite List Code Messed Up

Does it ?? It works only if both pointer are aligned on word address (even address), otherwise --> BUS error. It checks for things like alignment and length before using the long code. If either pointer can't do a long read or it's not at least a long worth of bytes, it does a byte move. It does NO...
by Chilly Willy
Thu Nov 16, 2017 3:59 pm
Forum: Megadrive/Genesis
Topic: Sprite List Code Messed Up
Replies: 22
Views: 419

Re: Sprite List Code Messed Up

Good point. Maybe there should be a thread on 68000 gcc optimizations and what versions they're good for. Things like the while (i--), or that gcc 7 with -Ofast will store longs when it can instead of bytes in a loop like this: for (x=0; x<w; x++) *dp++ = *sp++; where dp and sp are both uint8_t poin...
by Chilly Willy
Wed Nov 15, 2017 4:13 pm
Forum: Demos
Topic: Papi Commando RELOAD !! *SgdK* - Megadrive
Replies: 46
Views: 2211

Re: Papi Commando RELOAD !! *SgdK* - Megadrive

Woah, that's an awesome way to start a level! :o :D
by Chilly Willy
Wed Nov 15, 2017 4:06 pm
Forum: Megadrive/Genesis
Topic: Sprite List Code Messed Up
Replies: 22
Views: 419

Re: Sprite List Code Messed Up

Page 8-6 of the 68000 user manual clearly states that clr.l reg takes 6 cycles. It's been well known for a long time that moveq #0,d0 is faster than clr.l d0. You only use clr when you need to only clear a byte or word and need the upper bits to remain unchanged. And yes, gcc is a terrible way to le...
by Chilly Willy
Tue Nov 14, 2017 6:13 pm
Forum: Megadrive/Genesis
Topic: Best way to manage sprites
Replies: 5
Views: 156

Re: Best way to manage sprites

There are still some oooooooold compilers for the 68000 on for DOS/Windows, Amiga, and Atari ST. If you don't want a compiler that will need an emulator (or a 20-something year-old machine) to run, go with gcc. :lol: As for the gcc 680x0 ABI, all parameters are pushed as longs on the stack, preceded...
by Chilly Willy
Sat Nov 11, 2017 4:11 am
Forum: Megadrive/Genesis
Topic: Sprite List Code Messed Up
Replies: 22
Views: 419

Re: Sprite List Code Messed Up

You got inconsistent size problems everywhere. First you're moving bytes, move.b (sprite_count), d5 ; sprint count in d5 move.b d5, d6 ; d6 is used to calculate the sprite table offset cmp.b #80, d5 then you're dealing with them as a different size not knowing what was in the upper parts of the regi...
by Chilly Willy
Thu Nov 09, 2017 10:55 pm
Forum: Megadrive/Genesis
Topic: Sprite List Code Messed Up
Replies: 22
Views: 419

Re: Sprite List Code Messed Up

Code: Select all

lsl.b #$03, d6
The shift size is too small. If d6 is more than 31, it'll overflow the byte. Make that lsl.w.
by Chilly Willy
Tue Nov 07, 2017 4:06 pm
Forum: Super 32X
Topic: "The Question" ported to 32X
Replies: 19
Views: 583

Re: "The Question" ported to 32X

That's really weird; AFAIK, there's no routine on the engine that would reach beyond the size of the compiled code. Taking a guess: when the setting is set to HW, it'll get confused if the ROM has a weird size and end up trimming part of the end of the ROM (and mirror everything before that). Then ...
by Chilly Willy
Mon Nov 06, 2017 4:21 pm
Forum: Super 32X
Topic: "The Question" ported to 32X
Replies: 19
Views: 583

Re: "The Question" ported to 32X

EDIT2: The current NeoMyth menu mirrors rom data to make certain games work that expect mirroring. Could you share an example of such a game? I'm not aware of any games that are relying on mirroring. God, it's been YEARS since I worked on that, but there were two types of mirroring needed, hence th...
by Chilly Willy
Sun Nov 05, 2017 8:09 pm
Forum: Super 32X
Topic: "The Question" ported to 32X
Replies: 19
Views: 583

Re: "The Question" ported to 32X

Okay, you can tell it's been awhile since I worked on the NeoMyth menu. I already solved this problem. When hovering over the game in the menu, press A to pull up the options, then move down one option to ROM Aliasing. Change it from HW to OFF (press C to change the setting) and you're good to go - ...
by Chilly Willy
Sun Nov 05, 2017 5:50 pm
Forum: Super 32X
Topic: "The Question" ported to 32X
Replies: 19
Views: 583

Re: "The Question" ported to 32X

Dug out my MED (older model, not a new X series), and it works fine. So the issue is why it fails on the NeoMyth. This is literally the ONLY thing that works on MED and fails on NeoMyth, and that will drive me crazy until I figure it out. :D On the NeoMyth, you get a green screen and a '$' in the to...
by Chilly Willy
Wed Nov 01, 2017 10:56 pm
Forum: Super 32X
Topic: "The Question" ported to 32X
Replies: 19
Views: 583

Re: "The Question" ported to 32X

That's a good point. I'm using the NeoMyth. If I can find my MED, I'll try it on that and see if it's the flash cart or the 32X that's the issue. Also, I'm using it on a Model 2 Genesis + Model 2 CD + Launch 32X. It's possible the CD might be an issue here as well.
by Chilly Willy
Fri Oct 27, 2017 9:43 pm
Forum: Super 32X
Topic: "The Question" ported to 32X
Replies: 19
Views: 583

Re: "The Question" ported to 32X

Hmm - since updating my nvidia driver, FUSION no longer runs. It also doesn't run on real hardware - you get a green screen with a $ in the upper left corner. EDIT: Forgot to restart after installing new nvidia driver. Weird that it doesn't REQUIRE a restart like a new kernel, but doesn't work on ev...
by Chilly Willy
Wed Oct 25, 2017 1:24 am
Forum: Tools
Topic: Sierra 68000 C Compiler
Replies: 4
Views: 223

Re: Sierra 68000 C Compiler

It's crazy, but it makes a certain sense - it's aimed at businesses where "cheap" is equated as "crap". In the mid-90s, I knew a company that made a video tool they sold on the Amiga for ~$500. They didn't sell too many. Someone advised them to port it to the SGI and charge ten times the price, so t...
by Chilly Willy
Tue Oct 24, 2017 3:35 pm
Forum: Tools
Topic: Sierra 68000 C Compiler
Replies: 4
Views: 223

Re: Sierra 68000 C Compiler

Holy crap! They wanted $2000 for that? You could have gotten an Atari ST/TT or an Amiga for less than that price and used a free or cheap C compiler. Even SAS/C wasn't that expensive!