Sets bits in a CSR using a 5-bit unsigned immediate.
Details
CSRRSI atomically reads CSR csr into rd, then sets bits in the CSR corresponding to set bits in the zero-extended 5-bit immediate. If the immediate is zero, no bits are modified.
Pseudocode Operation
t = CSRs[csr]; CSRs[csr] = t | zext(uimm); R[rd] = t;