On Fri, 19 Jan 2018 16:06:51 +0000 Luke Kenneth Casson Leighton lkcl@lkcl.net wrote:
so he asked, also, what would it take to get things ready within a year, to hand over the ASIC-based design to MOSIS, for them to turn it into an ASIC, and i said "a team of engineers would need to be paid for". he asked - and please note the question very carefully - "would USD 250,000 be enough?" to which i replied (genuinely) yes... if done carefully. software also has to be taken care of.
A libre risc-v soc would indeed be great.
we worked out that if you put in 2 nyuzi cores and managed to halve the number of instructions / pixel by replacing critical path blocks with hardware-rendering ones, you'd end up at about 25% the performance of MALI400 and that i feel would be "good enough" for a first version. i'd be interested to hear what people think, here.
25% of MALI400 is not enough for even mobile games: it is enough for spinning windows ala Compiz, but that can also be done with much less. So if the goal is something usable, rather than a platform to kickstart nyuzi development on, targeting lower perf with lower power usage would be better.
Now, I don't remember if video decode blocks would be in the RISC parts or in nyuzi. GPUs are usually good at colorspace conversion and scaling, so if there are no dedicated blocks for those, then the nyuzi core should be targeted/sized at that usage. Bicubic upscaling + color conversion to fullhd - the texture units, memory bandwidth and compute parts need to have enough oomph.
Radeon R300 parts are capable of that. I'm not sure how that maps to % of Mali.
- Lauri