ststwl.v
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/**************************************************************************
* *
* Copyright (C) 1994, Silicon Graphics, Inc. *
* *
* These coded instructions, statements, and computer programs contain *
* unpublished proprietary information of Silicon Graphics, Inc., and *
* are protected by Federal copyright law. They may not be disclosed *
* to third parties or copied or duplicated in any form, in whole or *
* in part, without the prior written consent of Silicon Graphics, Inc. *
* *
*************************************************************************/
// $Id: ststwl.v,v 1.2 2002/11/22 00:34:20 rws Exp $
/* Project Reality
MDP
Created by Mike M. Cai 5/25/94
*/
module ststwl( att_data_out,
att_data_in, dx, dy,
left_major, load, ncyc, clk, start_gclk);
output [15:0] att_data_out;
input [26:0] att_data_in, dx;
input [16:0] dy;
input left_major, load, ncyc, clk, start_gclk;
wire [26:0] att_accum, dx_dir, dx_dir_m;
reg [26:0] att_cur_s, att_cur_m;
wire [15:0] att_data_out;
reg [15:0] att_dy_out;
reg comp_new;
always @(posedge clk)
if (start_gclk) begin
att_cur_m = load ? att_data_in : att_accum;
att_cur_s <= (comp_new | load) ? att_cur_m : att_cur_s;
comp_new <= load ? ~ncyc : (ncyc ? ~comp_new : comp_new);
att_dy_out <= att_accum[26:11];
end
assign dx_dir_m = (dx ~^ {27{left_major}}) & {27{comp_new}};
assign dx_dir = comp_new ? dx_dir_m : {dy, 10'b0};
adder27b adder ( .sum(att_accum), .a(att_cur_s), .b(dx_dir),
.ci(~left_major & comp_new));
// assign att_data_out = (comp_new & ncyc) ? att_cur_s[26:11] : att_dy_out ;
assign att_data_out = (comp_new & ncyc) ? att_dy_out : att_cur_s[26:11];
endmodule // ststwl