4 ms·
I guess these are the bitmanip stuff you mention https://github.com/riscv/riscv-bitmanip https://github.com/riscv/riscv-bitmanip They're a proposal only (and I
by throwaway_pdp09 6y ago
I guess these are the bitmanip stuff you mention https://github.com/riscv/riscv-bitmanip https://github.com/riscv/riscv-bitmanip
They're a proposal only (and I don't think they're an official proposal), and having read them it seems the guy just shoehorned in anything he could think of. I'm curious to see how much of it will be accepted.
- tux3 6y agoI can see why you'd say that yeah, it could probably use some trimming down of the less widely applicable instructions. But I don't otherwise think having a set of disparate, seemingly unrelated instructions is a bad thing for something like bitmanip, as long as they all pull their weight. I think they do have an official working group. I remember reading a few months ago their working GCC PoC had ~4% dynaminc instruction reduction in SPECint and some 5% perf improvement. Nothing world-shattering, but considering that the instructions are pretty lightweight to implement in hardware, the cost-benefit seems decent. (Full disclosure: I am not a RISC-V member or particularly invested in bitmanip, just some random person going off of what I remember!)