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View Full Version : No CPS2 after all



oninotsume
July 31st, 2006, 14:56
I just took a look over at NJs web page, and he had something interesting written at the very bottom.

PSPだとデバッグの作業が辛いので、MAME 0.106のmusashi 68KコアをC68Kに置き換え
たものをデバッグ用の環境として作成。ついでに暗号化ROMの実行にも対応。

"Debugging on the PSP is very difficult so I replaced the 68K Core with the the MAME 0.106 Musashi 68K Core to give myself a better debugging environment. Replacing the core also allows encrypted roms to be read."

I find the last part about being able to read encrypted roms the most fascinating because he stated earlier, the inability to run fast memory access on the 68K Core with encrypted roms as one of his main reasons for refusing to even try CPS2 emulation.

EDIT:
So after I wrote this I looked back at NJ's page and he had this to say.

C68Kの暗号化対応のチェックということで、試しにPSPでCPS2を動かしてみました。
やりもしないでできないとか言っていると思われるのも嫌ですしね(笑)。
結論から言うと、予想通りの厳しい結果でした。最初からこうだとやる気もおきないわけで。
何度も書いていますが、私の手でPSP用のCPS2エミュレータを作ることは無いです。

In an effort to check the C68K encryption I booted up a CPS2 game on the PSP. I didn't want anyone to think that I was just saying I wouldn't do it without even trying:) In any case it ended up being just as bad as I thought it was going to be, and when it's like this from the get go, I'm really not up for tackling it. I've written it a thousand times before, but I'll say it again, I won't be the one to release a CPS2 emu on the PSP.

・最もサイズの小さなゲームでも、全てのROMを読み込むメモリを確保できない。
 PSPは最大でも24MBしかプログラムで使用するメモリを確保できないわけですが
 (実質データ用として確保できるのは20MB程度)、CPS2の場合、暗号化の為に
 4MBのメモリを余分に確保しなければなりません。これがものすごく厳しいです。

There isn't enough available memory on the PSP to load in all of even the smallest CPS2 game.
The PSP only allows a maximum of 24mb of ram for program operation, actual data use at 20, but the CPS2 encryption requires an extra 4mb to be held in reserve making emulation extremely difficult.

・描画がCPS1よりもさらに複雑で実行速度をあげるのが難しい。
 試しにssf2を動かしてみたわけですが、サウンド無し、スプライトのプライオリティを
 一切処理しない、Raster Effectsなしにもかかわらず以下のような状態。
 fpsを見てください。20fpsも出ません。
CPS2 rendering is even more complex than CPS1 making any speed improvements difficult.
I ran ssf2 as a test without sound, zero sprite prioritization, and no raster effects, yet even so I could only get around 20fps.
SSF2 - プレイヤー選択画面
http://neocdz.hp.infoseek.co.jp/psp/snap/ssf2_02.png
http://neocdz.hp.infoseek.co.jp/psp/snap/ssf2_03.png
ステージによっては多少速度が上がることも。(CPS1のSF2のステージ)
In some instances the speed increased as in this CPS1 SF2 stage.
SSF2 - プレイ中画面3

So that's the end of that I guess.

Sorry for the messy post, but I'm hitting the hay.

Mr.Denny
July 31st, 2006, 15:47
I think you may be right!


:)

Here`s hoping!

Baboon
July 31st, 2006, 16:29
Fingers crossed! :)

Pumped'Up
August 1st, 2006, 04:42
Eh NJ, I am so thankful for your fantastic CPS-1 emulator. It is by far the best emulator for PSP ever.

If we ever see a CPS-2 emu, it'll be my dream come true....I don't know what else to say, but please don't give up!!!