forked from Github_Repos/cvw
65 lines
2.3 KiB
Systemverilog
65 lines
2.3 KiB
Systemverilog
|
|
///////////////////////////////////////////
|
|
// cnt.sv
|
|
//
|
|
// Written: Kevin Kim <kekim@hmc.edu>
|
|
// Created: 4 February 2023
|
|
// Modified:
|
|
//
|
|
// Purpose: Count Instruction Submodule
|
|
//
|
|
// Documentation: RISC-V System on Chip Design Chapter 15
|
|
//
|
|
// 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 cnt #(parameter WIDTH = 32) (
|
|
input logic [WIDTH-1:0] A, RevA, // Operands
|
|
input logic [4:0] B, // Last 5 bits of immediate
|
|
input logic W64, // Indicates word operation
|
|
output logic [WIDTH-1:0] CntResult // count result
|
|
);
|
|
|
|
//count instructions
|
|
logic [WIDTH-1:0] czResult; // count zeros result
|
|
logic [WIDTH-1:0] cpopResult; // population count result
|
|
logic [WIDTH-1:0] lzcA, popcntA;
|
|
|
|
//only in rv64
|
|
if (WIDTH==64) begin
|
|
//clz input select mux
|
|
mux4 #(WIDTH) lzcmux64(A, {A[31:0],{32{1'b1}}}, RevA, {RevA[63:32],{32{1'b1}}}, {B[0],W64}, lzcA);
|
|
//cpop select mux
|
|
mux2 #(WIDTH) popcntmux64(A, {{32{1'b0}}, A[31:0]}, W64, popcntA);
|
|
end
|
|
//rv32
|
|
else begin
|
|
assign popcntA = A;
|
|
mux2 #(WIDTH) lzcmux32(A, RevA, B[0], lzcA);
|
|
end
|
|
|
|
lzc #(WIDTH) lzc(.num(lzcA), .ZeroCnt(czResult[$clog2(WIDTH):0]));
|
|
popcnt #(WIDTH) popcntw(.num(popcntA), .PopCnt(cpopResult[$clog2(WIDTH):0]));
|
|
// zero extend these results to fit into width
|
|
assign czResult[WIDTH-1:$clog2(WIDTH)+1] = '0;
|
|
assign cpopResult[WIDTH-1:$clog2(WIDTH)+1] = '0;
|
|
|
|
mux2 #(WIDTH) cntresultmux(czResult, cpopResult, B[1], CntResult);
|
|
endmodule |