SpritesMind.Net

AFAIK, even when the DMA engine is set to completely take over the bus, the CPU can still execute code out of cache.

According to this FAQ, it was never released even in Japan: http://www.classicgaming.com/museum/faqs/megadfaq.shtml

Given how infrequently it's mentioned compared to the Meganet Modem (which is quite obscure), I suspect it was indeed cancelled before release.

Anyway, last I checked the Saturn ...

evildragon wrote:Sega did make a keyboard for the Genesis at one point.. They also made a mouse too..

The mouse was released and I own one, but AFAIK a keyboard wasn't. They may have developed a prototype, but it was never available for sale.

Hmm, I like the idea. I've actually been considering the possibility of a SCUMM-style system for Sega CD - would this be something similar, or would it be more low-level?
I'm not familiar enough with SCUMM to say and for that matter I'm not even sure what the final product will look like at this ...

AFAIK, the Saturn PS/2 keyboard adapter should be electrically compatible with the Genesis. I started hacking a DB-9 connector onto one, but never finished.

About the ram bus, i always thought it was full 32bit... I still think it is, else, why would the cartridge access be 3-4 times slower?
I believe access to the cartridge is split evenly betweenthe 68K and the 32X with the 32X getting one access per 68K bus cycle. The SH-2s run at 3 times the clock ...

Presumably because he doesn't have a flash cart, but does have a Sega CD.

Generally speaking in a synthetic benchmark you loop over a set of operations. Ideally you wantt his set of operations to closely model a real world process, but for your purposes a simple benchmark that executes a decent variety of different instructions and addressing modes would probably suffice ...

I am not pmjobin. I either go by Mask of Destiny or my real name, Michael Pavone, on the internet.

You're other major problem is probably the byte access. I don't remember how wide the bus is on the SH-2, but you should be able to write the framebuffer at at least 2 to 4 times as fast. Using the ...

I think for what you're doing, it would be faster to just use one SH-2 and halt the other one. If you're mostly just pushing pixels around, you're probably going to be memory bandwidth constrained not CPU cycle constrained. Using 2 CPUs is just going to put extra stress on the memory bus. If you're ...

That looks more or less correct to me. I think you need to pay attention to the cartridge port's !CE line though so you only get mapped to the 0x0 to 0x3FFFFF range (or 0x400000 to 0x7FFFFF if !CART_IN is left to float), but I'm not sure as it's been a while since I last read up on the cartridge ...

To be honest, I'm not entirely surprised that no one here is really interested. It would seem just about everyone here is already comfortable with lower level languages and the Sega CD obviously isn't very popular (a pure Genesis version would probably be theoretically possible, but producing a ...

So I take there is no interest then? Oh well.

I'm pretty sure !TIME is pulsed for any access to $A13XXX (or maybe just $A130XX). Anyway, I believe that the mapper used in SFS II The New Challengers is more or less the official mapper. Although it's the only officially licensed game that's greater than 32MBit, several other games appear to use ...

How big is the ROM on your cart? if it's 2MB (16Mbit) or less you can just map your SRAM to odd addresses starting at 0x200001 and set up your ROM header appropriately. I know of at least one game that's set up like this (Virtual Pinball or something like that) and I seem to recall that the SRAM ...