On Mon, Mar 18, 2013 at 4:53 AM, Nicolas Boulay <[email protected]> wrote:

> Registers are a very precious ressources. Memory are more and more slower
> than the CPU (it's even worse from the latency point of view). So having a
> register code for /dev/null is a coslty solution, if we have constraint on
> the instruction size. A cpu with large code have more pressure to reduce
> the code size, than a gpu where the code is smaller.
>
> MSP430 use 16 and 32 bits instruction size, 32 bits instruction use the
> second 16 part as immediat, it's quite clean.
>
> One of the new cpu have a specific encoding for constant. It's like having
> 3 bits that code 8 values includes -1, 0, 1, 2, 4, 8, 16, the most used
> constant to avoid to use larger code.
>
> - Large instruction world is coslty only on large code
>


> - dependencies between register is always a plague for performance on
> pipeline
>


> - Register and register adress space is one of the most precisous
> ressources of a cpu
>

All very true.



> - immediat could be coded as enum or constant name for the most used value


Yes.  This is equivalent to having a shared extension to the register file
that contains constants.


I have gaps in my knowledge about some architectures, so there are some
features (such as a constant file) that I am more inclined to adopt because
earlier architectures have proved them to be useful.  Once I understand
more of this, I'll be more willing to consider creative new features, and
by that point I hope to have some infrastructure for testing.



>
>
> Nicolas
>
>
>
> --
Timothy Normand Miller, PhD
Assistant Professor of Computer Science, Binghamton University
http://www.cs.binghamton.edu/~millerti/
Open Graphics Project
_______________________________________________
Open-graphics mailing list
[email protected]
http://lists.duskglow.com/mailman/listinfo/open-graphics
List service provided by Duskglow Consulting, LLC (www.duskglow.com)

Reply via email to