diff --git a/rv32_opcodes.sv b/rv32_opcodes.sv
index b713ee0..e5f6462 100644
--- a/rv32_opcodes.sv
+++ b/rv32_opcodes.sv
@@ -43,6 +43,8 @@
 `define RV32_INSTR_FENCE_I 32'b???????_?????_?????_001_?????_0001111
 `define RV32_INSTR_ECALL   32'b0000000_00000_00000_000_00000_1110011 /* SYSTEM */
 `define RV32_INSTR_EBREAK  32'b0000000_00001_00000_000_00000_1110011
+`define RV32_INSTR_MRET    32'b0011000_00010_00000_000_00000_1110011
+`define RV32_INSTR_WFI     32'b0001000_00101_00000_000_00000_1110011
 `define RV32_INSTR_CSRRW   32'b???????_?????_?????_001_?????_1110011
 `define RV32_INSTR_CSRRS   32'b???????_?????_?????_010_?????_1110011
 `define RV32_INSTR_CSRRC   32'b???????_?????_?????_011_?????_1110011