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0 pointspanick21_4y ago0 comments

Part of the idea is to create standard ways to do certain things and then hope compiler writers generation code according to that. That will allow more chip designers to take advantage of those if they want to.

They spent a lot of time and effort on making sure the decoding pretty good and useful for high performance implementations.

RISC-V is designed for very small and very large system. At some point some tradeoffs need to be made but these are very reasonable and most of the time no a huge problem.

For the really specialized cases where you simply can't live with those extra instruction, those will be added to the standard and then some profiles will include them and others not. If those instructions are really as vital as those that want them claim, they will find their way into many profiles.

Saying RISC-V is 'terrible' because of those choices is not fair way of evaluating it.

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userbinator4y ago

RISC-V is designed for very small and very large system

That's exactly the problem --- there is no one-size-fits-all when it comes to instruction set design.

panick21_OP4y ago

There is a trade-off but there is overall far more value in having it be unified.

The trade-offs are mostly very small or non existent once you consider the standard extensions that different use cases will have.

Overall having a unified open instruction set is far better then hand designing many different instruction sets just to get marginal improvement. Some really extreme application might require that, but for the most part the whole indsutry could do just fine with RISC-V. Both on the low and on the high end, and in fact better then most of the alternative all things considered.

If integer checking is really the be all end all and without it RISC-V can not be successful without it, it will be added and it will be pulled into all the profiles. If it is not actually that relevant then it wont. If it is very useful for some verticals and not others, it will be in those profiles and not in others.

ddingus4y ago

>overall far more value in having it be unified.

>[...]

>If integer checking is really the be all end all and without it RISC-V can not be successful without it, it will be added and it will be pulled into all the profiles. If it is not actually that relevant then it wont. If it is very useful for some verticals and not others, it will be in those profiles and not in others.

So which is it? Unified or something else?

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