CSRRC

Control Status Register Read and Clear

CSRRC rd, csr, rs1

Reads the old value of the CSR, then clears bits in the CSR based on the mask in rs1.

Encoding

Binary Layout

csr

31:20

rs1

19:15

011

14:12

rd

11:7

1110011

6:0

 

Format I-Type

Opcode 0x00003073

Extension Zicsr

Operands

• rd
  Dest (Old Value)
• csr
  CSR Address
• rs1
  Bit Mask

Example

CSRRC x10, sstatus, x5

// Clears bits in 'sstatus' where x5 is 1.

Related

More in Zicsr

Reference

View in RISC-V Unprivileged ISA Specification ↗ RISC-V ISA Manual

Description

CSRRC atomically reads CSR csr into rd, then clears the bits in the CSR that correspond to bits set in rs1. If rs1 is x0, no bits are modified.

Operation

t = CSRs[csr]; CSRs[csr] = t & ~R[rs1]; R[rd] = t;