On Fri, Nov 24, 2023 at 12:04:09PM +0100, Jonas Oberhauser wrote:
Unfortunately, at least last time I checked RISC-V still hadn't gotten such instructions. What they have is the *semantics* of the instructions, but no actual opcodes to encode them. I argued for them in the RISC-V memory group, but it was considered to be outside the scope of that group.
(Sorry for the late, late reply; just recalled this thread...)
That's right. AFAICT, the discussion about the native load-acquire and store-release instructions was revived somewhere last year within the RVI community, culminating in the so called Zalasr-proposal [1]; Brendan, Hans and Andrew (+ Cc) might be able to provide more up-to- date information about the status/plans for that proposal.
(Remark that RISC-V did introduce LR/SCs and AMOs instructions with acquire/release semantics separately, cf. the so called A-extension.)
Andrea