Search found 17 matches

by TMorita
Thu Jan 22, 2009 8:36 pm
Forum: Demos
Topic: Gameboy on 32X
Replies: 77
Views: 56790

Just as an example; a function that contains only "return 0;" gets compiled into: mov.l r14,@-r15 mov #0,r0 mov r15,r14 mov r14,r15 rts mov.l @r15+,r14 Plain awesomeness.. :roll: That could be reduced by 67%. And it just goes on like that. GCC is creating a stack frame. You need to use -fomit-frame...
by TMorita
Thu Jan 22, 2009 8:29 pm
Forum: Super 32X
Topic: Cache coherency
Replies: 8
Views: 9892

I think triggering an interupt on each write would be a lot slower than just accessing all data with the cache turned off. Interupt handling on the SH-2 takes a lot of cycles. ... . Yes. It's faster to do this the correct way, e.g. by just using the cache-through address space on both SH2s for shar...
by TMorita
Sun Jan 18, 2009 8:19 pm
Forum: Video Display Processor
Topic: Is DMA useful ?
Replies: 30
Views: 29410

Re: Is DMA useful ?

Hi you all. I'm wondering a silly question : is DMA useful ? I'm talking about DMA 1 : transfer data from ROM/RAM to VRAM, not DMA-fill or DMA-copy. ... You have a bigger experience than I. So tell me. In what case is DMA transfer useful ? It's useful for many things. On most games the sprite is do...
by TMorita
Mon Jan 12, 2009 10:36 pm
Forum: Sound
Topic: Genesis - SNES audio comparison
Replies: 161
Views: 103206

... Had every game from 1988-1997 been in the 32 Megabit range, this would be an entirely different discussion. The fact that ROM was typically limited to 8-16 Megabits actually limited what both the Genesis and SNES could theoretically produce. The Genesis earned its reputation when the average RO...
by TMorita
Sun Jan 11, 2009 12:29 am
Forum: Sound
Topic: Genesis - SNES audio comparison
Replies: 161
Views: 103206

I've worked on a SNES game which was ported to Genesis, so I have a bit of experience with both systems. The SNES audio was generally considered easier to work with than the Genesis. You could use sampled audio and get exactly the sound you wanted, whereas with the Genesis you had to figure out the ...
by TMorita
Wed Oct 08, 2008 6:12 pm
Forum: Super 32X
Topic: 32X overclocking
Replies: 8
Views: 12106

Re: 32X overclocking

Once of the things I've read was that the only reason the 32X's SH-2's didn't run at 28MHz was because the clock from the Genesis was multiplied 3x. However, since we have half multipliers these days, or perhaps a 28MHz oscillator, could the 32X be overclocked? Or would this render the 32X un-usabl...
by TMorita
Wed Oct 08, 2008 5:45 pm
Forum: Announcement
Topic: Honorable members
Replies: 14
Views: 28534

... he is the co-inevntor of the Comix Zone's game engine :shock: this guy sure know a lot about the Genesis VDP timings and internal mechanism ;) Just noticed I was mentioned here - thanks for the kind words! Yep, I was involved in the design of the Comix Zone engine. I didn't code any of it, thou...
by TMorita
Thu Aug 14, 2008 7:51 pm
Forum: Megadrive/Genesis
Topic: Programming in C - Some doubts
Replies: 10
Views: 8033

Don't forget to declare the pointer as pointing to a volatile value, otherwise the compiler is allowed to remove all the writes except the last one.

Toshi
by TMorita
Thu Aug 14, 2008 7:50 pm
Forum: Megadrive/Genesis
Topic: Don't forget volatile
Replies: 0
Views: 8914

Don't forget volatile

Oops, sorry. clicked on "new thread" instead of "post reply".

Toshi
by TMorita
Thu Aug 14, 2008 7:47 pm
Forum: Super 32X
Topic: Cell Shading
Replies: 12
Views: 12726

It's called 'Cel shading' (aka 'Toon shading'), not 'Cell'. Just read wiki article to understand what you want.. I don't think it's possible for 32x (for realtime in-game graphics). Depends. Cel shading is comprised of two techniques: quantized lighting and black outlines. The quantized lighting ca...
by TMorita
Wed Jun 04, 2008 7:49 pm
Forum: Super 32X
Topic: Super VDP
Replies: 167
Views: 205636

OK, back to the game. Thanks to TotoOnTheMoon (forgive the case), and following TascoDLX, I've used compression for my tiles : 4 bits/pixels point to 16 palettes of 16 colors. Thus, I load half less memory (bandwidth hungry), and my CPUs work on computing, and not memory operations. I get 278k cycl...
by TMorita
Wed Jun 04, 2008 6:07 am
Forum: Super 32X
Topic: Super VDP
Replies: 167
Views: 205636

.... About the DAC quality on YM2612, in fact it's even worst you think : I wrote a Z80 driver which can normally plays 4 channels of 8 bits signed sample at 16 Khz. I discovered than even with good delays and no interruption on Z80 the DAC quality is really bad :-/ You can see it on this topic : h...
by TMorita
Wed Jun 04, 2008 6:04 am
Forum: Super 32X
Topic: Super VDP
Replies: 167
Views: 205636

... Generally, multiple channels of 8 bit samples are added together rather than using 10 bit samples. At 11 kHz (the sample rate games like Doom use), you can have eight 8 bit sample streams added together without worrying about saturation. I tried this once (8 channel audio) on the 32x and it did...
by TMorita
Tue Jun 03, 2008 6:42 pm
Forum: Super 32X
Topic: Super VDP
Replies: 167
Views: 205636

I really don't know. I want to fully assign both SH2s to display. But the PWM remains available to the 68k. OK, Thank you. I have read some documentations, but I haven't found my answer : In 256 colors mode, how many palette can you manage. The same for both "planes", or more ? Understand that I'm ...
by TMorita
Thu May 29, 2008 5:07 pm
Forum: Super 32X
Topic: Super VDP
Replies: 167
Views: 205636

Hi Tasco. Thanks for interest. I'm not sure you understand how BT/S works Sure I can be wrong. I think that BT/S is like BT, except that the instruction after BT/S is executed before. Is it correct ? ... Not correct. With a pipelined CPU, the CPU normally fetches a few instructions past the current...