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path: root/rv64cpu/rtl/core/id_ex_reg.sv
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Diffstat (limited to 'rv64cpu/rtl/core/id_ex_reg.sv')
-rw-r--r--rv64cpu/rtl/core/id_ex_reg.sv27
1 files changed, 26 insertions, 1 deletions
diff --git a/rv64cpu/rtl/core/id_ex_reg.sv b/rv64cpu/rtl/core/id_ex_reg.sv
index 7c780ee..e88ce17 100644
--- a/rv64cpu/rtl/core/id_ex_reg.sv
+++ b/rv64cpu/rtl/core/id_ex_reg.sv
@@ -113,7 +113,7 @@ module id_ex_reg
);
always_ff @(posedge clk) begin
- if (rst || flush_en) begin
+ if (rst) begin
ex_pc <= '0;
ex_rs1_rdata <= '0;
ex_rs2_rdata <= '0;
@@ -144,6 +144,31 @@ module id_ex_reg
ex_is_sfence_vma <= '0;
ex_is_fence <= '0;
ex_is_fence_i <= '0;
+ end else if (flush_en) begin
+ ex_alu_op <= ALU_ADD; // NOP is effectively ADD x0, x0, 0
+ ex_alu_src1_sel <= '0;
+ ex_alu_src2_sel <= '0;
+ ex_is_word_op <= '0;
+ ex_is_branch <= '0;
+ ex_branch_op <= BRANCH_EQ;
+ ex_is_jump <= '0;
+ ex_is_load <= '0;
+ ex_is_store <= '0;
+ ex_mem_size <= '0;
+ ex_reg_write_en <= '0; // VERY IMPORTANT: Do not write to regfile on NOP
+ ex_rd_addr <= '0;
+ ex_wb_sel <= '0;
+ ex_is_csr <= '0;
+ ex_csr_op <= '0;
+ ex_illegal_instr <= '0;
+ ex_is_ecall <= '0;
+ ex_is_ebreak <= '0;
+ ex_is_mret <= '0;
+ ex_is_sret <= '0;
+ ex_is_wfi <= '0;
+ ex_is_sfence_vma <= '0;
+ ex_is_fence <= '0;
+ ex_is_fence_i <= '0;
end else if (~stall_en) begin
ex_pc <= id_pc;
ex_rs1_rdata <= id_rs1_rdata;