////////////////////////////////////////////////////////////////////// //// //// //// multiply for 8051 Core //// //// //// //// This file is part of the 8051 cores project //// //// http://www.opencores.org/cores/8051/ //// //// //// //// Description //// //// Implementation of multipication used in alu.v //// //// //// //// To Do: //// //// Nothing //// //// //// //// Author(s): //// //// - Simon Teran, simont@opencores.org //// //// - Marko Mlinar, markom@opencores.org //// //// //// ////////////////////////////////////////////////////////////////////// //// //// //// Copyright (C) 2001 Authors and OPENCORES.ORG //// //// //// //// This source file may be used and distributed without //// //// restriction provided that this copyright statement is not //// //// removed from the file and that any derivative work contains //// //// the original copyright notice and the associated disclaimer. //// //// //// //// This source file is free software; you can redistribute it //// //// and/or modify it under the terms of the GNU Lesser General //// //// Public License as published by the Free Software Foundation; //// //// either version 2.1 of the License, or (at your option) any //// //// later version. //// //// //// //// This source is distributed in the hope that it will be //// //// useful, but WITHOUT ANY WARRANTY; without even the implied //// //// warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR //// //// PURPOSE. See the GNU Lesser General Public License for more //// //// details. //// //// //// //// You should have received a copy of the GNU Lesser General //// //// Public License along with this source; if not, download it //// //// from http://www.opencores.org/lgpl.shtml //// //// //// ////////////////////////////////////////////////////////////////////// // // CVS Revision History // // $Log: oc8051_multiply.v,v $ // Revision 1.9 2003/04/02 11:26:21 simont // updating... // // Revision 1.8 2002/09/30 17:33:59 simont // prepared header // // // ver: 2 markom // changed to two cycle multiplication, to save resources and // increase speed // // ver: 3 markom // changed to four cycle multiplication, to save resources and // increase speed // synopsys translate_off `include "oc8051_timescale.v" // synopsys translate_on module oc8051_multiply (clk, rst, enable, src1, src2, des1, des2, desOv); // // this module is part of alu // clk (in) // rst (in) // enable (in) // src1 (in) first operand // src2 (in) second operand // des1 (out) first result // des2 (out) second result // desOv (out) Overflow output // input clk, rst, enable; input [7:0] src1, src2; output desOv; output [7:0] des1, des2; // wires wire [15:0] mul_result1, mul_result, shifted; // real registers reg [1:0] cycle; reg [15:0] tmp_mul; assign mul_result1 = src1 * (cycle == 2'h0 ? src2[7:6] : cycle == 2'h1 ? src2[5:4] : cycle == 2'h2 ? src2[3:2] : src2[1:0]); assign shifted = (cycle == 2'h0 ? 16'h0 : {tmp_mul[13:0], 2'b00}); assign mul_result = mul_result1 + shifted; assign des1 = mul_result[15:8]; assign des2 = mul_result[7:0]; assign desOv = | des1; always @(posedge clk or posedge rst) begin if (rst) begin cycle tmp_mul end else begin if (enable) cycle tmp_mul end end endmodule
