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riscv / riscv-j-extension

Working Draft of the RISC-V J Extension Specification
https://jira.riscv.org/browse/RVG-128
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Zjpm: CSR definitions. hspm is not needed. Instead should define substitute CSR (vspm) #23

Closed deepak0414 closed 1 year ago

deepak0414 commented 1 year ago

Current spec (0.3) defines mpm, hspm, spm and upm CSRs. Following other risc-v extensions, hspm CSR is actually not needed.

Regular spm CSR can work for HS mode. For VS mode, we would need vspm. (see example in privilege spec, e.g vsstatus, vsie, vstvec)

With this scheme HS-mode PM (bit 26:18) bits wouldn't be needed.

Here is the short write up on this https://docs.google.com/document/d/1tiKV1co4JcpJr2AvfILn6hhzqvcKJKjL-v6pqLrP02w/edit

martinmaas commented 1 year ago

Addressed in fd7220807e1405ba9b5de38d9d4ac26e73312128 (Chapter 3)