csrrs

Atomically read and set bits in a CSR. Reads the value of the CSR, zero-extends the value to `XLEN` bits, and writes it to integer register `xd`. The initial value in integer register `xs1` is treated as a bit mask that specifies bit positions to be set in the CSR. Any bit that is high in `xs1` will cause the corresponding bit to be set in the CSR, if that CSR bit is writable. Other bits in the CSR are not explicitly written.

csrrs xd, csr, xs1