cva6/core/cvxif_fu.sv

76 lines
3 KiB
Systemverilog

// Copyright 2024 Thales DIS France SAS
//
// Licensed under the Solderpad Hardware Licence, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// SPDX-License-Identifier: Apache-2.0 WITH SHL-2.0
// You may obtain a copy of the License at https://solderpad.org/licenses/
//
// Original Author: Guillaume Chauvon
// Functional Unit for the CoreV-X-Interface
// Handles Result interface and exception forwarding to next stages.
module cvxif_fu
import ariane_pkg::*;
#(
parameter config_pkg::cva6_cfg_t CVA6Cfg = config_pkg::cva6_cfg_empty,
parameter type exception_t = logic,
parameter type x_result_t = logic
) (
// Subsystem Clock - SUBSYSTEM
input logic clk_i,
// Asynchronous reset active low - SUBSYSTEM
input logic rst_ni,
// CVXIF instruction is valid - ISSUE_STAGE
input logic x_valid_i,
// Transaction ID - ISSUE_STAGE
input logic [CVA6Cfg.TRANS_ID_BITS-1:0] x_trans_id_i,
// Instruction is illegal, determined during CVXIF issue transaction - ISSUE_STAGE
input logic x_illegal_i,
// Offloaded instruction - ISSUE_STAGE
input logic [ 31:0] x_off_instr_i,
// CVXIF is ready - ISSUE_STAGE
output logic x_ready_o,
// CVXIF result transaction ID - ISSUE_STAGE
output logic [CVA6Cfg.TRANS_ID_BITS-1:0] x_trans_id_o,
// CVXIF exception - ISSUE_STAGE
output exception_t x_exception_o,
// CVXIF FU result - ISSUE_STAGE
output logic [ CVA6Cfg.XLEN-1:0] x_result_o,
// CVXIF result valid - ISSUE_STAGE
output logic x_valid_o,
// CVXIF write enable - ISSUE_STAGE
output logic x_we_o,
// CVXIF destination register - ISSUE_STAGE
output logic [ 4:0] x_rd_o,
// CVXIF result interface
input logic result_valid_i,
input x_result_t result_i,
output logic result_ready_o
);
assign result_ready_o = 1'b1;
assign x_ready_o = 1'b1; // Readyness of cvxif_fu is determined in issue stage by CVXIF issue interface
// Result signals
assign x_valid_o = x_illegal_i && x_valid_i ? 1'b1 : result_valid_i;
assign x_result_o = result_i.data;
assign x_trans_id_o = x_illegal_i ? x_trans_id_i : result_i.id;
assign x_we_o = result_i.we;
assign x_rd_o = result_i.rd;
// Handling of illegal instruction exception
always_comb begin
x_exception_o = '0; // No exception in this interface
if (x_illegal_i && x_valid_i) begin
x_exception_o.valid = '1;
x_exception_o.cause = riscv::ILLEGAL_INSTR;
if (CVA6Cfg.TvalEn)
x_exception_o.tval = x_off_instr_i; // TODO Optimization : Set exception in IRO.
end
end
endmodule