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Add mscratch CSR

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Graham Edgecombe 2017-12-31 11:13:07 +00:00
parent 73717d320d
commit 26ec3542e4
1 changed files with 9 additions and 0 deletions
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9
rv32_csrs.sv
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@ -2,6 +2,7 @@
`define RV32_CSRS
`define RV32_CSR_MISA 12'h301
`define RV32_CSR_MSCRATCH 12'h340
`define RV32_CSR_CYCLE 12'hC00
`define RV32_CSR_TIME 12'hC01
`define RV32_CSR_INSTRET 12'hC02
@ -46,6 +47,7 @@ module rv32_csrs (
logic [31:0] write_value;
logic [31:0] new_value;
logic [31:0] mscratch;
logic [63:0] cycle;
logic [63:0] instret;
@ -54,6 +56,7 @@ module rv32_csrs (
always_comb begin
case (csr_in)
`RV32_CSR_MISA: read_value_out = `RV32_MISA_VALUE;
`RV32_CSR_MSCRATCH: read_value_out = mscratch;
`RV32_CSR_CYCLE: read_value_out = cycle[31:0];
`RV32_CSR_TIME: read_value_out = cycle[31:0];
`RV32_CSR_INSTRET: read_value_out = instret[31:0];
@ -76,6 +79,12 @@ module rv32_csrs (
end
always_ff @(posedge clk) begin
if (write_in) begin
case (csr_in)
`RV32_CSR_MSCRATCH: mscratch <= new_value;
endcase
end
cycle <= cycle + 1;
instret <= instret + instr_retired_in;
end