cvw/src/fpu/fregfile.sv
2023-03-24 17:32:25 -05:00

57 lines
1.9 KiB
Systemverilog

///////////////////////////////////////////
// fregfile.sv
//
// Written: David_Harris@hmc.edu 9 January 2021
// Modified: James Stine
//
// Purpose: 3R1W 4-port register file for FPU
//
// Documentation: RISC-V System on Chip Design Chapter 13
//
// A component of the CORE-V-WALLY configurable RISC-V project.
//
// Copyright (C) 2021-23 Harvey Mudd College & Oklahoma State University
//
// SPDX-License-Identifier: Apache-2.0 WITH SHL-2.1
//
// Licensed under the Solderpad Hardware License v 2.1 (the “License”); you may not use this file
// except in compliance with the License, or, at your option, the Apache License version 2.0. You
// may obtain a copy of the License at
//
// https://solderpad.org/licenses/SHL-2.1/
//
// Unless required by applicable law or agreed to in writing, any work distributed under the
// License is distributed on an “AS IS” BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
// either express or implied. See the License for the specific language governing permissions
// and limitations under the License.
////////////////////////////////////////////////////////////////////////////////////////////////
`include "wally-config.vh"
module fregfile (
input logic clk, reset,
input logic we4, // write enable
input logic [4:0] a1, a2, a3, a4, // adresses
input logic [`FLEN-1:0] wd4, // write data
output logic [`FLEN-1:0] rd1, rd2, rd3 // read data
);
logic [`FLEN-1:0] rf[31:0];
integer i;
// three ported register file
// read three ports combinationally (A1/RD1, A2/RD2, A3/RD3)
// write fourth port on rising edge of clock (A4/WD4/WE4)
// write occurs on falling edge of clock
always_ff @(negedge clk) // or posedge reset)
if (reset) for(i=0; i<32; i++) rf[i] <= 0;
else if (we4) rf[a4] <= wd4;
assign #2 rd1 = rf[a1];
assign #2 rd2 = rf[a2];
assign #2 rd3 = rf[a3];
endmodule // regfile