Search found 256 matches

by tomaitheous
Sat Apr 26, 2008 3:36 am
Forum: Blabla
Topic: Yamaha internal waveform info
Replies: 17
Views: 13227

TmEE co.(TM) wrote:OK, I'll run some tests when I've finished my exam tomorrow.
Awesome :D
by tomaitheous
Fri Apr 25, 2008 2:11 pm
Forum: Blabla
Topic: Yamaha internal waveform info
Replies: 17
Views: 13227

AFAIK, the sampling rate is around 52KHz (53203424(PAL) / something), accuracy 9 or 10 bits on discrete Yamaha YM2612 and about 12 bits on Sega internal YM2612. The bit count is an estimate, which I estimated by listening the amount of aliasing noise produced and comparing with WAV files degraded t...
by tomaitheous
Fri Apr 25, 2008 2:12 am
Forum: Blabla
Topic: Yamaha internal waveform info
Replies: 17
Views: 13227

Yamaha internal waveform info

Hey guys, Not sure if this is the correct forum (or place) for this, but I'm looking for the resolution and length of the internal sine wave used by the YM2612, OPL2, and some other Yamaha FM chips. I *think* I remember TmEE mentioning the 2612 had a 9bit resolution on the sine wave, but no mention ...
by tomaitheous
Wed Apr 23, 2008 5:38 am
Forum: Regen
Topic: Old Regen pages
Replies: 547
Views: 325682

AamirM wrote: Absolutely not. I hate hacks.
That's good to hear (just asking - you work fast :wink: )
by tomaitheous
Tue Apr 22, 2008 1:37 pm
Forum: Regen
Topic: Old Regen pages
Replies: 547
Views: 325682

AamirM wrote:I think Regen will be the first emu to run it correctly :) .
You're not using emulation hacks for specific games, right?
by tomaitheous
Sat Apr 19, 2008 6:46 am
Forum: Video Display Processor
Topic: VLBitmap2Scroll
Replies: 30
Views: 17601

Moreover, some of those even run at H32, and you know that there things are a lot slower... Via DMA, 256x224 takes 4.797 frames to update the screen in H32 where as 320x224 takes 4.856 frames to update. Fairly close and you save vram space using H32. So it's not really slower - actually it's a hair...
by tomaitheous
Sat Apr 19, 2008 5:55 am
Forum: Video Display Processor
Topic: VLBitmap2Scroll
Replies: 30
Views: 17601

And you've tested this on the real hardware? I would actually want to know from where did Sega get all those timings. Maybe they just took into account VBlank? Because this subroutine will continue sending data while in active scan. I mean, the Mega Drive isn't as slow as the tech docs say. Otherwis...
by tomaitheous
Sat Apr 19, 2008 3:23 am
Forum: Video Display Processor
Topic: VLBitmap2Scroll
Replies: 30
Views: 17601

Sik wrote:Already saw that. And 10FPS (you) vs. 30FPS (me) *shot*
I'd like to know how you're getting a faster transfer rate than local to vram DMA? H40 mode with 224 active scanlines is 7380bytes per frame and you're transferring 17920bytes per frame without DMA!? Please explain.
by tomaitheous
Thu Mar 27, 2008 3:29 pm
Forum: Regen
Topic: Old Regen pages
Replies: 547
Views: 325682

org wrote:Breakpoints to access at address are usually called memory watches.
From my experience, memory watch is just that. To keep a display of a certain byte/word/whatever of an address. Breakpoint!=watch, though I'm sure some debugger somewhere switches around the terminology.
by tomaitheous
Thu Feb 21, 2008 9:02 am
Forum: Sound
Topic: MOD/S3M player for the MD
Replies: 31
Views: 20333

Also, there's no hardware volume specifically for channel 6? Or is that just in DAC mode? If not, then you should be able to work around that issue by shifting the lower 8bit part(only, not the MSB) to the right one bit. That will get half the volume for the lower part, but at the cost of outputtin...
by tomaitheous
Wed Feb 20, 2008 11:43 pm
Forum: Sound
Topic: MOD/S3M player for the MD
Replies: 31
Views: 20333

True, it should be tested first. I have no plans to immediately write a player (got my hands full with a bunch of other projects). Though, given that I've seen this method working fairly decent on a 7khz timer to playback 3.5khz with double the bit rate by interleaving, I'm fairly certain 32khz is h...
by tomaitheous
Tue Feb 19, 2008 9:55 pm
Forum: Sound
Topic: MOD/S3M player for the MD
Replies: 31
Views: 20333

That would make a 9 bit sample, not a 16 bit sample. Interleaving ADDS the samples. Two 8 bit samples added together gives a 9 bit sample. You would need a method of multiplying the samples to make two 8 bit sample yield a 16 bit sample. Hehe, well I forget a step. You need to play the lower eight ...
by tomaitheous
Tue Feb 19, 2008 10:41 am
Forum: Sound
Topic: MOD/S3M player for the MD
Replies: 31
Views: 20333

Yeah, all mixing and limiting would be done on the 68k side. All the z80 would do is stream the final output. HardWareMan use that way. He is on this forum, maybe it's worth for you to contact with him? Will do :D I was thinking, if one were to go the route where the z80 just wrote to the YM DAC an...
by tomaitheous
Sun Feb 17, 2008 10:21 pm
Forum: Sound
Topic: MOD/S3M player for the MD
Replies: 31
Views: 20333

Yeah by "clipping" i also understand "limiting", no clipping is just "overflowing" and in this case it's very noticable even on a single byte. As Shiru said, limiting a sample is heavy and can't be handle on Z80 if you're already severals channels mix... Yeah, all mixing and limiting would be done ...
by tomaitheous
Sat Feb 16, 2008 11:57 am
Forum: Sound
Topic: MOD/S3M player for the MD
Replies: 31
Views: 20333

I'm pretty sure that I can hear one wrong sample (yes, just one byte or word) of mixed stream, if it broke waveform, i.e. if it's actual clipping (not limiting). If you'll do limiting, i.e. handle clipping as I said above - yes, it will be not so easy to hear. But it can't be measured in % of clipp...