[Oberon] Risc-5 Instructions statistics
waltergallegos at vera.com.uy
Tue Feb 19 13:29:13 CET 2019
I try to post on Oberon list, no success after many days...
Yes for me the focus is the special hardware not the micro-controller.
In FPGA arena this must be the focus, let me try to explain for what I
insist at point.
Industry rules have well know constraints.
To use a 28 USD chip I need justify that this chip provide the best
solution. A basic rule in industry is : a project use FPGA because is
the only practical solution if not use a micro-controller.
In this context, chose a bigger component adding 6.44 USD (+23%) to the
costs when an ARM cost around 3.5 USD could be hard to justify. Beside
the cost of a chip is the development cost that in case of ARM is
significantly lower because it is a better know component than an FPGA.
Combined this cost with Paul numbers I could conclude that in the case
of DSP blocks for multiplication adding 23% to the cost of each unit
optimize only 0.16% of the software. A questionable conclusion, I agree,
but illustrate the type of analysis that we need do.
Can be argument that for cases where multiplication is lot much used the
software be optimized lot more, but the bottle neck, again based in Paul
number, are load and store operations. If a project have lot of math
build a dedicated processor ( a fixed state machine ) in hardware. I use
this approach all times for DSP as image processing, filtering,
convolutions, interpolation, etc.
This is the mind switch that many software designers need be to do for
work with FPGA. If not they are using a costly all terrain truck as a
I insist because I would like to see a growing community but for that it
has to fit into the industry and play by it rules.
Feel free to post this in Oberon list.
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