Anyone know what DMA does?

Discussion in 'Supercard' started by imgod22222, Nov 16, 2006.

  1. imgod22222
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    imgod22222 GBAtemp's Original No-faced Member

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    I know DMA lets data transfer that's CPU-independent, but when does this come into effect on the DS? How does it affect your everyday player?
     
  2. legendofphil

    legendofphil Phil no Densetsu

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    Direct Memory Access

    It allows data to transfer quicker in theory.
     
  3. lookout

    lookout GBAtemp Board Room

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    legendofphil you doing his homework [​IMG]

    kidding.. well speak...
     
  4. imgod22222
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    imgod22222 GBAtemp's Original No-faced Member

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    in theory but in reality??? Any difference yet?
     
  5. Hitto

    Hitto MKDS Tournament Winner

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    I noticed a speed-up in video playback, for example FF3 and Castlevania DoS.

    Also, saving your progress in contact on a SCSD was UTTERLY SLOW compared to a CF card. I guess that would be one of the improvements, but I haven't replayed contact ever since I fried my savegame.
     
  6. bollocks

    bollocks GBAtemp Advanced Fan

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    does it have any effect at all on the CF version, then?
     
  7. zalman

    zalman Advanced Member

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    It seems to be mostly to help the Supercard SD, the Lite is already faster.
     
  8. rippon

    rippon Member

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    DMA is a method to copy data from one section of memory to another, without involving the processor.

    When a processor does a memory copy, it must execute a series of instructions to read data from a memory address into a register, then write the data in that register to another address, and repeat. This involves several instructions, and each read/write cycle is generally limited to the bandwidth of the processor (i.e. a 32 bit machine copies 32 bits at a time).

    DMA, on the other hand, is a hardware solution that does all of the work automatically and doesn't involve the processor (and thus no loop operations or anything like that). Not only is it often twice as fast, but it leaves the processor free to do other work.