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Thread: Some questions about the PSP's hardware

  
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    Default Some questions about the PSP's hardware

    Found this on wikipedia's article about the PSP
    Spoiler:

    PSP CPU Chip:
    • Sony CXD2962GG CPU
    • Based on MIPS R4000 32-bit Core
    • 90 nm Semiconductor CMOS Process
    • 1-333 MHz (set at 222 MHz by default) @ 1.2 V
    • 16 KB Instruction Cache / 16 KB Data Cache
    • SiP:
      • 32 MB eDRAM @ 2.6 Gbps
      • Embedded FPU
      • Embedded Vector FPU @ 2.6 GFLOPS
      • Embedded Graphics Core:
      • 1-166 MHz (set at 111 MHz by default) @ 1.2 V
      • 256-bit Bus at 5.3 Gbps
      • 2 MB eDRAM (VRAM)
      • 3D Curved Surface and 3D Polygon
      • Compressed Textures
      • Hardware Clipping, Morphing, Bone(8)
      • Hardware Tessellator
      • Bézier surface, Bézier curve and B-Spline (NURBS)
        • 4×4, 16×16, 64×64 Subdivision
      • Rendering Engine and Surface Engine
      • Pixel Fill Rate: 664 Megapixels/s
      • Up to 33 Million Polygon/s (with Transform and Lighting)
      • 24-bit Full Color: RGBA
    • 128-bit Bus at 2.6 Gbit/s
    • 3D-CG Extended Instruction Set

    Memory:
    • Samsung K5E5658HCM-D060
    • Main Memory: 32 MB 333 MHz DDR SDRAM (64 MB )
    • 8 MB reserved for Kernel


    It says there the main cpu has it's own 32MB of edram. Anyone knows how to use this? Or I don't need to care coz the compiler uses this already?

    Spoiler:

    Media Engine Chip:
    • Sony CXD1876 CPU
    • Based on MIPS R4000 32-bit Core
    • 90 nm Semiconductor CMOS Process
    • 1-333 MHz (set at 222 MHz by default) @ 1.2 V
    • 16 KB Instruction Cache / 16 KB Data Cache
    • SiP:
      • 2 MB eDRAM @ 2.6 Gbps
      • Embedded Virtual Mobile Engine (VME) Sound Core
        • Reconfigurable DSP Engine
        • 1-166 MHz (set at 166 MHz by default) @ 1.2 V
        • 128-bit Bus
        • 24-bit Data Path
        • 5 GFlops
      • Embedded MPEG-4 (H.264/AVC) hardware decoder
      • Embedded FPU
    • 128-bit Bus @ 2.6 Gbit/s


    says there the VME does 5 gflops. almost twice as fast as the vfpu. This means a huge(?) performance improvement(plus saw on a pdf from sony that it can operate in parallel a cpu, in the PSP's case, the ME). It's not that I think reverse engeering is easy but why is it that we haven't had access(control of the vme like how we do with the vfpu) to this?

    Last edited by RNB_PSP; 02-14-2011 at 07:28 AM.

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    jenny's Avatar
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    The 32MB of eDRAM is the ram of the psp. The "e" in eDRAM standing for embedded(it's in the same package as the flash). The 2000, 3000, and GO have 64MB of it instead of the 32MB.

    The VME looks to be handling just the sound. I could be wrong about it, but I can't find much more than that. You could reconfigure it(since it is a DSP), but that would require you getting the toolchain(s) to do it.

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    Quote Originally Posted by jenny View Post
    The 32MB of eDRAM is the ram of the psp. The "e" in eDRAM standing for embedded(it's in the same package as the flash). The 2000, 3000, and GO have 64MB of it instead of the 32MB.

    The VME looks to be handling just the sound. I could be wrong about it, but I can't find much more than that. You could reconfigure it(since it is a DSP), but that would require you getting the toolchain(s) to do it.
    Well, the way it was listed(there at wikipedia's article) looks like it was another memory(like how the me has its own 2mb edram plus it can access the main ram). It made me think that the main cpu also have its own edram aside from the system ram.

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    Yeah, it does look that way at first. Also what's interesting, is Samsung doesn't have any information on the ram/flash chip.

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    Quote Originally Posted by jenny View Post
    Yeah, it does look that way at first. Also what's interesting, is Samsung doesn't have any information on the ram/flash chip.
    Well, I guess (almost)every part of the PSP was custom made by Sony. I still want to know how to use the VME. It's so powerful if that 5 gflops there is true.

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    Indeed it would. I'm trying to find more information about it, but cannot. Also 2MB isn't much to work with unless it can move data between the 2MB of the graphics/sound and the 32MB of the rest of the system. I'm sure it can though.

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    Quote Originally Posted by jenny View Post
    Indeed it would. I'm trying to find more information about it, but cannot. Also 2MB isn't much to work with unless it can move data between the 2MB of the graphics/sound and the 32MB of the rest of the system. I'm sure it can though.
    Yeah, you can. and 2mb edram of the ME is different from the 2mb vram. Only the ME(and VME?) can access it, and the vram is invisible to the ME(iirc).

    Quote Originally Posted by ps2dev.org
    Base Address Length Description
    0×00010000 0×00004000 (16 KiB) Allegrex Scratchpad
    0×04000000 0×00200000 (2 MiB) Ge VRAM
    0×08000000 0×00800000 (8 MiB) Allegrex Kernel memory
    0×08800000 0×01800000 (24 MiB) Allegrex User memory
    Yeah. There's no extra 32mb there.

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    Ah, ok then.

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