Search found 2757 matches

by Stef
Wed Jan 31, 2007 11:33 am
Forum: Super 32X
Topic: Cache coherency
Replies: 8
Views: 5395

I believe cache latency is 2 or 3 cycles. In Gens i got many 32X speed inacuracies because of the different latencies (RAM / ROM ...) Virtua Racing use a lot the internal cache. It uses it for all the 3D transformation : MAC instructions combined to internal cache, the game appears to be nicely opti...
by Stef
Wed Jan 31, 2007 10:07 am
Forum: Sound
Topic: how can i do music on megadrive?
Replies: 288
Views: 122256

Well, in fact i just wrote the 4 bits PCM player for Z80 but the result is really disapointing... My idea was to use the PSG as 3 DAC capable of playing 4 bits PCM data. The PSG codes the envelope on 4 bits so by setting the tone to 0 we can use PSG channel as 4 bits DAC by modifying quickly the env...
by Stef
Wed Jan 31, 2007 9:53 am
Forum: Super 32X
Topic: Cache coherency
Replies: 8
Views: 5395

I think the best soluce is still to avoid working on the same piece of memory when possible ;)
by Stef
Wed Jan 31, 2007 9:48 am
Forum: Tools
Topic: Easy68K?
Replies: 21
Views: 10752

QB IDE is somewhat... primitive ?
I'm currently using CodeBlock and before i used DevCPP. Both offer the advantage of being free :)
by Stef
Tue Jan 30, 2007 7:05 pm
Forum: Announcement
Topic: New game in developement... CA the Meowian
Replies: 14
Views: 11246

Almost games work in this way, they update the invisible part of the scroll layer datas and use DMA to upload sprite pattern at each frame. It's probably the easiest way of doing a classic scrolling game.
by Stef
Tue Jan 30, 2007 10:56 am
Forum: Tools
Topic: [GensKMod] version 0.6 is out
Replies: 22
Views: 10312

About genskmod... I was benchmarking my last demo and i figured out that genskmod had a Step/Step animation. It is Shift+Esc... So I ran my demo and pressed Shift+Esc and the demo was moving almost each time... If the Step/Step is really 1Frame/1Frame, it means that my demo runs almost 60fps... Are...
by Stef
Mon Jan 29, 2007 10:06 am
Forum: Sound
Topic: how can i do music on megadrive?
Replies: 288
Views: 122256

Audio converter in QB, converts ordinary 8-bit PCM wav to 4-bit PCM: open "wavfile.wav" for binary as #1 'open source file open "convert.4bt" for binary as #2 'destination file Lenght&=lof(1)-58 'get the lenght - header seek #1, 58 'skip header for i& = 0 to Lenght& 'loop until all data processed n...
by Stef
Mon Jan 29, 2007 10:05 am
Forum: Sound
Topic: how can i do music on megadrive?
Replies: 288
Views: 122256

I see... Maybe it was 4bit adpcm... I cannot check since it was rented game... If i remember correctly, the 32x documentation mentions that GEMS3.0 supports "Delta 4bit" DAC... I suspect it is a sort of adpcm-looking format specialy designed for the z80. Delta 4 bits is exactly the ADPCM 4 bits stu...
by Stef
Sun Jan 28, 2007 9:48 pm
Forum: Announcement
Topic: Forum is now open to public
Replies: 49
Views: 32552

It is ;)
Welcome on the board, glad to see you here Christuserloeser :)
by Stef
Sun Jan 28, 2007 9:47 pm
Forum: Sound
Topic: how can i do music on megadrive?
Replies: 288
Views: 122256

Are you sure about the GTA3 music in 4 bits ? Maybe you mistake with the MS ADPCM 4 bits or other 4 bits audio format which use some compression method. Pure 4 bits PCM can't be "good quality" bt at least it can be acceptable. I did more tests, i now get better result but still dispointting. I first...
by Stef
Sun Jan 28, 2007 12:07 pm
Forum: Sound
Topic: how can i do music on megadrive?
Replies: 288
Views: 122256

:arrow: I have another question :) I tried to make a DAC player that use 4bit samples. So i took a 8bit .wav sample and removed the lower 4bits (set to 0) and i get... a background "CHHHHHH" over my sample. I don't think it is normal, or i misunderstood something about 4bit samples? :arrow: I also ...
by Stef
Sat Jan 27, 2007 1:53 pm
Forum: Super 32X
Topic: Master SH2 BIOS
Replies: 11
Views: 6855

I can't confirm but i don't think that having only one CPU accessing permit a lower CAS value. normally the sub CPU work in cycle steal mode, the main CPU has priority on the BUS : sub CPU access when main CPU don't need it.
by Stef
Sat Jan 27, 2007 9:06 am
Forum: Super 32X
Topic: Master SH2 BIOS
Replies: 11
Views: 6855

the main problem with 32x is the DRAM / VRAM speed... Are you sure the SDRAM speed, or FB speed is the main problem ? I would have guessed some missings features were much more a concern : no fill polygon, no scroll no scaling/rotation/distortion ... no hardware graphics function. Anyway, there are...
by Stef
Fri Jan 26, 2007 3:12 pm
Forum: Mega/SegaCD
Topic: CDROM reading speed
Replies: 24
Views: 15138

Hi Stef :D Hehe no.. I will stick to emulation dev for now, but I'm very interested to see how the homebrew genny scene is coming along. It's good to see that a lot of people still are making things for those good old consoles, that motivates me . I had that datasheet floating around for a few year...
by Stef
Thu Jan 25, 2007 10:22 am
Forum: Mega/SegaCD
Topic: CDROM reading speed
Replies: 24
Views: 15138

Hi Gerrie !

Glad to see you here :)
Do you plan to do some genny dev :p ?

I think your document is even more complete the one i used for megaCD CDC/CDD emulation development (i got something similar but not as clean and complete)