| ///////////////////////////////////////////////////////////////////// |
| //// //// |
| //// Non-restoring unsigned divider //// |
| //// //// |
| //// Author: Richard Herveille //// |
| //// richard@asics.ws //// |
| //// www.asics.ws //// |
| //// //// |
| ///////////////////////////////////////////////////////////////////// |
| //// //// |
| //// Copyright (C) 2002 Richard Herveille //// |
| //// richard@asics.ws //// |
| //// //// |
| //// 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 SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY //// |
| //// EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED //// |
| //// TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS //// |
| //// FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL THE AUTHOR //// |
| //// OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, //// |
| //// INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES //// |
| //// (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE //// |
| //// GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR //// |
| //// BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF //// |
| //// LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT //// |
| //// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT //// |
| //// OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE //// |
| //// POSSIBILITY OF SUCH DAMAGE. //// |
| //// //// |
| ///////////////////////////////////////////////////////////////////// |
| |
| // CVS Log |
| // |
| // $Id: div_uu.v,v 1.3 2003-09-17 13:08:53 rherveille Exp $ |
| // |
| // $Date: 2003-09-17 13:08:53 $ |
| // $Revision: 1.3 $ |
| // $Author: rherveille $ |
| // $Locker: $ |
| // $State: Exp $ |
| // |
| // Change History: |
| // $Log: not supported by cvs2svn $ |
| // Revision 1.2 2002/10/31 13:54:58 rherveille |
| // Fixed a bug in the remainder output of div_su.v |
| // |
| // Revision 1.1.1.1 2002/10/29 20:29:10 rherveille |
| // |
| // |
| // |
| |
| //synopsys translate_off |
| //`include "timescale.v" |
| //synopsys translate_on |
| |
| module div_uu(clk, ena, z, d, q, s, div0, ovf); |
| |
| // |
| // parameters |
| // |
| parameter z_width = 16; |
| parameter d_width = z_width /2; |
| |
| // |
| // inputs & outputs |
| // |
| input clk; // system clock |
| input ena; // clock enable |
| |
| input [z_width -1:0] z; // divident |
| input [d_width -1:0] d; // divisor |
| output [d_width -1:0] q; // quotient |
| output [d_width -1:0] s; // remainder |
| output div0; |
| output ovf; |
| reg [d_width-1:0] q; |
| reg [d_width-1:0] s; |
| reg div0; |
| reg ovf; |
| |
| // |
| // functions |
| // |
| function [z_width:0] gen_s; |
| input [z_width:0] si; |
| input [z_width:0] di; |
| begin |
| if(si[z_width]) |
| gen_s = {si[z_width-1:0], 1'b0} + di; |
| else |
| gen_s = {si[z_width-1:0], 1'b0} - di; |
| end |
| endfunction |
| |
| function [d_width-1:0] gen_q; |
| input [d_width-1:0] qi; |
| input [z_width:0] si; |
| begin |
| gen_q = {qi[d_width-2:0], ~si[z_width]}; |
| end |
| endfunction |
| |
| function [d_width-1:0] assign_s; |
| input [z_width:0] si; |
| input [z_width:0] di; |
| reg [z_width:0] tmp; |
| begin |
| if(si[z_width]) |
| tmp = si + di; |
| else |
| tmp = si; |
| |
| assign_s = tmp[z_width-1:z_width-d_width]; |
| end |
| endfunction |
| |
| // |
| // variables |
| // |
| reg [d_width-1:0] q_pipe [d_width-1:0]; |
| reg [z_width:0] s_pipe [d_width:0]; |
| reg [z_width:0] d_pipe [d_width:0]; |
| |
| reg [d_width:0] div0_pipe, ovf_pipe; |
| // |
| // perform parameter checks |
| // |
| // synopsys translate_off |
| initial |
| begin |
| if(d_width !== z_width / 2) |
| $display("div.v parameter error (d_width != z_width/2)."); |
| end |
| // synopsys translate_on |
| |
| integer n0, n1, n2, n3; |
| |
| // generate divisor (d) pipe |
| always @(d) |
| d_pipe[0] <= {1'b0, d, {(z_width-d_width){1'b0}} }; |
| |
| always @(posedge clk) |
| if(ena) |
| for(n0=1; n0 <= d_width; n0=n0+1) |
| d_pipe[n0] <= #1 d_pipe[n0-1]; |
| |
| // generate internal remainder pipe |
| always @(z) |
| s_pipe[0] <= z; |
| |
| always @(posedge clk) |
| if(ena) |
| for(n1=1; n1 <= d_width; n1=n1+1) |
| s_pipe[n1] <= #1 gen_s(s_pipe[n1-1], d_pipe[n1-1]); |
| |
| // generate quotient pipe |
| always @(posedge clk) |
| q_pipe[0] <= #1 0; |
| |
| always @(posedge clk) |
| if(ena) |
| for(n2=1; n2 < d_width; n2=n2+1) |
| q_pipe[n2] <= #1 gen_q(q_pipe[n2-1], s_pipe[n2]); |
| |
| |
| // flags (divide_by_zero, overflow) |
| always @(z or d) |
| begin |
| ovf_pipe[0] <= !(z[z_width-1:d_width] < d); |
| div0_pipe[0] <= ~|d; |
| end |
| |
| always @(posedge clk) |
| if(ena) |
| for(n3=1; n3 <= d_width; n3=n3+1) |
| begin |
| ovf_pipe[n3] <= #1 ovf_pipe[n3-1]; |
| div0_pipe[n3] <= #1 div0_pipe[n3-1]; |
| end |
| |
| // assign outputs |
| always @(posedge clk) |
| if(ena) |
| ovf <= #1 ovf_pipe[d_width]; |
| |
| always @(posedge clk) |
| if(ena) |
| div0 <= #1 div0_pipe[d_width]; |
| |
| always @(posedge clk) |
| if(ena) |
| q <= #1 gen_q(q_pipe[d_width-1], s_pipe[d_width]); |
| |
| always @(posedge clk) |
| if(ena) |
| s <= #1 assign_s(s_pipe[d_width], d_pipe[d_width]); |
| endmodule |
| |
| |
| |