[CHERI-RISC-V] In capability mode compressed move is capability move #771
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This ensures that addi 0 is no longer incorrectly compressed to c.cmove in capability mode. The difference here is that addi 0 should clear the capability metadata, but if we compress it c.mv (which behaves as CMove in capability mode) we retain the capability metadata. This commit also adds patterns to ensure that CMove is compressed to c.cmove in capability mode (but not in integer mode). NOTE: this should be restricted to standards-compatible mode only since ISAv8/9 did not define a pattern for compressed cmove. For example, QEMU only supports this when running in standards compliant mode: CTSRD-CHERI/qemu@4f95f3f
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This is not ready to be merged since the HW and QEMU don't support it. @PeterRugg FYI |
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This ensures that addi 0 is no longer incorrectly compressed to c.cmove in capability mode. The difference here is that addi 0 should clear the capability metadata, but if we compress it c.mv (which behaves as CMove in capability mode) we retain the capability metadata. This commit also adds patterns to ensure that CMove is compressed to c.cmove in capability mode (but not in integer mode).
NOTE: this should be restricted to standards-compatible mode only since ISAv8/9 did not define a pattern for compressed cmove. For example, QEMU only supports this when running in standards compliant mode: CTSRD-CHERI/qemu@4f95f3f