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Mali 628 floating point precision

Note: This was originally posted on 17th August 2013 at http://forums.arm.com

Could you please elaborate on a floating point precision of Mali-628?
What part of the IEEE754-2008 is supported in GPU? I.e. how many bits of precision we can get (medump) ?

Thank you in advance
Maxim

http://blogs.arm.com/multimedia/318-arm-mali-t604-new-gpu-architecture-for-highest-performance-flexibility/
  • Note: This was originally posted on 22nd August 2013 at http://forums.arm.com

    I'd suggest sticking to the Khronos precision minimums when picking qualifiers; it is very easy to write code which happens to work on one architecture which only works because that implementation provides more bits than technically necessary, which then fails on another device in weirdly wonderful and hard to debug ways.

    FWIW on all of the Mali GPUs:


    • highp is fp32
    • mediump is fp16
    • lowp is fp16
  • Note: This was originally posted on 26th August 2013 at http://forums.arm.com

    Thank you for the answer and for advice.
    Just to be sure let me dig a bit into the question.

    I understand that fp32 is a required and supported precision for the shaders.
    #1 Just to make it clear: Is it for both vertex and fragment shader?

    Let me also ask a question about HW itself:
    #2 Is fp32 means that the GPU HW actually uses at least 32 bits of floating point precision throughout an entire GPU pipe?

    Sorry for perhaps "blowing on water", but I got some "burns from milk".
    Best Wishes
    Maxim
  • Note: This was originally posted on 30th August 2013 at http://forums.arm.com

    Hi Maxim,

    1) The Mali-T600 series GPUs have a unified architecture, so there is no distinction between the vertex shader and fragment shader - they run on the same execution units.

    2) Yes, I believe so.

    Hope that helps, Pete
  • Note: This was originally posted on 30th August 2013 at http://forums.arm.com

    Many Thanks