CSR: treat CSRRS/CSRRC with rs1/uimm=0 as non-writes - #282
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csrrs/csrrc with a zero source is a read. Do not raise illegal-instruction on read-only CSRs, and do not take the write path that would skip mcycle/minstret auto-increment.
poemonsense
approved these changes
Sep 20, 2026
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csrrs/csrrc with a zero source is a read. Do not raise illegal-instruction on read-only CSRs, and do not take the write path that would skip mcycle/minstret auto-increment.