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KPOT0B
Joined: 09 Mar 2006
Posts: 9
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 Posted: Thu Jun 01, 2006 7:03 am Post subject: Media Engine vs Graphics Processor |
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Both(?) has MIPS cores.
Flash connected to Graphics Processor. What for?
DDR also connected to Graphics Processor. Reasonable.
Is the Media Engine just slave to Graphics Processor?
Or those are peers?
Where OS is executed? Which chip executes decrypted IPL? Which does decryption?
Do we have dual cpu system or singe processor with co-processor? |
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groepaz
Joined: 01 Sep 2005
Posts: 305
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| Posted: Thu Jun 01, 2006 7:22 am Post subject: |
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there are two cpus, then main cpu which executes the OS (and executes th ipl) and the media engine (ME). the graphics processor (GU) isnt a cpu. both media engine and GU have their local ram. decryption is initiated by the main cpu and handled by "KIRK", the decryption engine.
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KPOT0B
Joined: 09 Mar 2006
Posts: 9
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| Posted: Thu Jun 01, 2006 8:10 am Post subject: |
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According to http://hitmen.c02.at/files/yapspd/index.html
CXD2926 listed as Graphic Processor Chip
CXD1876 as ME
What is actually what? First one has GPU and CPU then? And ME just co-proc? |
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groepaz
Joined: 01 Sep 2005
Posts: 305
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| Posted: Thu Jun 01, 2006 8:39 am Post subject: |
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| Quote: | | What is actually what? First one has GPU and CPU then? And ME just co-proc? |
ME is a second CPU, not a coprocessor. and what actually is in what chip package is more or less speculation :)
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hitchhikr
Joined: 04 Feb 2006
Posts: 83
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| Posted: Fri Jun 02, 2006 9:46 pm Post subject: |
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groepaz: talking about the ME, is there a way to access it from game mode ? I know about the vector address being unreachable from this mode but there must be another way to do it using an already loaded library via a syscall or something ?
Btw: you may want to change the "mov" instruction into "move" in your IDA plugin. |
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groepaz
Joined: 01 Sep 2005
Posts: 305
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| Posted: Sat Jun 03, 2006 4:38 am Post subject: |
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| Quote: | | talking about the ME, is there a way to access it from game mode ? I know about the vector address being unreachable from this mode but there must be another way to do it using an already loaded library via a syscall or something ? |
as far as i am aware there is no way for the "user" (as in usermode) to upload custom code to the ME.
| Quote: | | you may want to change the "mov" instruction into "move" in your IDA plugin. |
uhm well, its not a standard instruction anyway :)
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Kojima
Joined: 26 Jun 2006
Posts: 275
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| Posted: Mon Jul 10, 2006 9:18 pm Post subject: |
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| How far has Media Engine coding got? I saw an old thread and people were pretty excited by running code on it, but has it be refined? Is it safe to code for the me in asm without fear of bricking your psp? |
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groepaz
Joined: 01 Sep 2005
Posts: 305
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PSP250
Joined: 19 Nov 2005
Posts: 12
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| Posted: Tue Oct 17, 2006 8:35 am Post subject: |
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| hitchhikr wrote: | | groepaz: talking about the ME, is there a way to access it from game mode ? I know about the vector address being unreachable from this mode but there must be another way to do it using an already loaded library via a syscall or something ? |
You might try to research how the sce(Video|Audio)codec* range of user mode functions work. They seem to be an usermode API layer which interacts with the ME.
Things like sceVideocodecGetEDRAM, sceVideocodecSetMemory and similar seem to make use of the ME to store the "codec program".
Since this thread is from July, I guess someone has already dissected these functions ;) |
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hitchhikr
Joined: 04 Feb 2006
Posts: 83
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| Posted: Tue Oct 17, 2006 9:49 am Post subject: |
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| Yes the issue has been resolved. |
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groepaz
Joined: 01 Sep 2005
Posts: 305
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TyRaNiD
Joined: 18 Jan 2004
Posts: 918
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| Posted: Wed Oct 18, 2006 1:52 am Post subject: |
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Well for pure interest sake, and we know how groepaz likes low level stuff ;)
The RPC works by posting an interrupt to the other processor using the following code:
| Code: | asm("sync\n");
_sw(1, 0xBC100044);
asm("sync\n");
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If you do that on the SC you interrupt (I think interrupt 31) the ME, on the ME is does the reverse. On the SC side that is wrapped up in sceSysregInterruptToOther.
Now as for semaphores there seems to be a shared lock register at 0xBC100048 which both the ME and the SC can write to and it used as a spin lock. Not tested it properly myself mind but still ;)
Have fun :P |
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