csrrw
Atomic Read/Write CSR
This instruction is defined by:
Synopsis
Atomically swap values in the CSRs and integer registers.
Read the old value of the CSR, zero-extends the value to XLEN bits,
and then write it to integer register rd.
The initial value in rs1 is written to the CSR.
If rd=x0, then the instruction shall not read the CSR and shall not
cause any of the side effects that might occur on a CSR read.
Decode Variables
Bits<12> csr = $encoding[31:20];
Bits<5> xs1 = $encoding[19:15];
Bits<5> xd = $encoding[11:7];Execution
-
Pruned, XLEN == 64
-
Original
%%LINK%func;check_csr;check_csr%%(csr, true, $encoding);
Bits<MXLEN> initial_value = X[xs1];
if (xd != 0) {
X[xd] = CSR[csr].sw_read();
}
CSR[csr].sw_write(initial_value);%%LINK%func;check_csr;check_csr%%(csr, true, $encoding);
Bits<MXLEN> initial_value = X[xs1];
if (xd != 0) {
X[xd] = CSR[csr].sw_read();
}
CSR[csr].sw_write(initial_value);