Makaron WIP (2010/04/02) - 模擬器

You know, seeing how it's become something of a tradition on this blog, I'm
surprised so many people fell for it again. Consider yourselves April Fools :)
Though I have to say, I rather liked the idea - it's hard to come up with
something both silly and still somewhat believable.

Anyway, there isn't a NAOMI emulator for Nintendo DS. Not now, not ever.
Let's look at the numbers here:
NAOMI has 2MB BIOS ROM, 32MB of main RAM, 16MB of VRAM for PowerVR2 and 8MB
RAM for AICA. That's not counting various smaller regions like OCRAM, NVRAM,
JVS and cart buffers, etc. Compare this to NDS lite that has 4MB of main
RAM... It't not enough to even get my DSF player running :) Maybe the
Dreamcast-only version would, since on DC there is only 2MB of AICA RAM, but
then again you need space for the code and data as well. Speaking of which,
the emulator itself requires large amounts of memory for recompiler code
buffers and dirty memory maps...

I'm not very big fan of ARM architecture. It almost feels like CISC with all
those control bits that change how each instruction is executed. And you
loose some of that functionality and registers when switching to Thumb mode.
I like SH4 better, it's only real weakness is immediate operands that are
bigger than 8 bits. Those must be loaded into registers with PC-relative
addressing, thus wasting precious cycles. Not surprisingly though it's not
that much of a problem in typical code.
SH4 is superscalar, pipelined CPU that can execute two instructions at a
time, including floating-point ones. It can do 4-element dot product in one
and matrix multiplication in 4 cycles. Fused multiply-add is also available.
In Dreamcast and NAOMI it's clocked at 200MHz and topped with some on-chip
peripherials like timers, DMA controller and MMU. On the other hand, all NDS
can offer is one ARM9 clocked at 66MHz and one ARM7 at 33MHz. Both have bus
width to main RAM reduced to 16 bits, which pretty much means Thumb mode
only. That's laughable by today standards and it would be even worse if not
for the WRAM and cache memory.

There is little point in comparing PowerVR2 and DS 3D engine :) Many newer
handhelds, while much faster on paper, can barely match the performance of
good old PVR2. This will probably be over soon with the new generation of SGX
chips and/or Tegra ones. The problem here is mainly the power consumption
that has to be kept down and also design limitations such as reduced bus
widths and smaller memories.

And let's not forget it's emulation we are talking about. It's all about
converting data and code on the fly - a process that is always pretty
expensive computation-wise. Then there's the basic rule of trading CPU speed
for memory usage and the other way around. Most emulators work at acceptable
speeds only thanks to extensive optimizations, some of them being pretty
clever :)



Now, I stated on my bio page that every now and then I will blog about things
not directly related to Makaron. With that in mind, and considering that I
don't have a Playstation 3 and have never used it - with or without Linux
installed - I feel like I'm entitled to bash SONY a bit. Yup, it's about the
3.21 update from yesterday.

First let me state that I fully understand SONY position on this. If I were
their boss I'd order pretty much the same move. They made a nice, secure
system and want to keep things that way, can't really blame them.
On the other hand removing an advertised feature (it only does gaming now :)
and only because of some very early hacking attempts? Seems like a bit of an
overkill, their PR will suffer. Slim users might not care for now but the
question is, what will come next? I mean it's pretty funny to see an update
that only blocks or removes otherwise useful functionality, and it's not
really optional either considering you loose PSN access otherwise and
possbily the ability to play future games/movies. This is a bit like hearing
"yer money or yer life" while being held at gunpoint. While there are two
choices here it's only theoretically.

There are ways to "fully crack" PS3. The most obvious is to obtain the master
decryption key(s) stored safely inside CELL. Or there might be a nasty bug in
one of the encrypted SPU programs that would leak some important data, or
bettr yet, serve as decryption box. There might be a way to load games
directly into RAM, bypassing the media checks - this one is tricky because
with the code still encrypted we can't be sure what the checks are and when
they will happen.

So, why remove Linux? I think it's because of RSX/SPUs lockout. It's there to
prevent people from writing homebrew games and programs that might look and
feel as good as SONY licensed products. Why? Because this is how SONY makes
money. Games made with free (or at least cheaper) 3rd party tools would also
be cheaper. You might think "but not as good" - well, possibly, but think
about TETRIS. It doesn't take super-realistic 3D to make a good game - I for
one find many of current generation games simply boring. It's less and less a
game now and more an interactive movie these days... And don't get me started
on PC DRM methods :)
This would of course violate EULA but that hasn't stopped people from trying
before... If there is money to be made, things like that suddenly don't
matter much.

I think the CELL encryption will remain secure for some time to come.
Eventually some people will decide it's time to profit from pirated BD media
and will start a manufacturing plant somewhere in Asia. That, or decap CELL
to make PS3 modchips. Whatever. For now though SONY is afraid of the lockout
being removed or bypassed. It remains to be seen if this move will help them,
or actually motivate various hackers to try harder...
Tags:makaron, naomi, ps3, sonyMusic:Ambient mix

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