Does riscv allow vector load/store access the same device address multiple times?

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RISC-V Instruction Set Manual

https://riscv.org/

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Does riscv allow vector load/store access the same device address multiple times? #1741

Open AlexGJL opened 20 hours ago

AlexGJL commented 20 hours ago

Does riscv allow vector load/store access the same device address multiple times like arm? it seems not easy to deal exception for hardware if not allowed.

gfavor commented 13 hours ago

See the "Precise vector traps" sub-section in the "Exception Handling" of the RVV spec - where it talks about what is and isn't allowed with respect to non-idempotent regions.

aswaterman commented 7 hours ago

Note also that RVV is a bit different than SVE in this regard: RISC-V has the vstart CSR, so can restart an instruction partway through at the position of the exception, whereas SVE does not have an equivalent feature and so must restart at the beginning.