strgba.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* unpublished proprietary information of Silicon Graphics, Inc., and *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: strgba.v,v 1.1 2002/03/28 00:26:13 berndt Exp $
/* Project Reality
MDP
Created by Mike M. Cai 5/23/94
*/
module strgba( att_data_out,
att_data_in, dx, dy, x_offset, y_offset,
left_major, load, ncyc, gclk);
output [7:0] att_data_out; // 8.0
input [20:0] att_data_in; // 10.11
input [21:0] dx; // s10.11
input [12:0] dy; // s10.2
input [1:0] x_offset, y_offset; // 0.2
input left_major, load;
input ncyc; // lsb of cycle_type
input gclk;
// wire [20:0] att_cur_m, att_accum, dx_dir;
wire [20:0] att_accum, dx_dir;
reg [20:0] att_cur_s;
wire [8:0] att_offset;
wire [7:0] att_clamp_value;
wire [7:0] att_clamped;
reg [7:0] att_data_out;
reg comp_new;
always @(posedge gclk)
begin
att_cur_s <= load ? att_data_in : att_accum;
comp_new <= load ? ~ncyc : ( ncyc ? ~comp_new : comp_new);
end
assign
dx_dir = (dx[20:0] ~^ {21{left_major}}) & {21{comp_new}};
adder21b adder ( .sum(att_accum), .a(att_cur_s), .b(dx_dir),
.ci(~left_major & comp_new));
strgbaoffseti dooffset ( .att_data_out(att_offset), .att_data_in(att_cur_s[19:9]),
.dx(dx[21:9]), .dy(dy),
.x_offset(x_offset), .y_offset(y_offset));
assign
// att_clamp_value = att_offset[7] ? 8'h0 : 8'hff,
att_clamp_value = {8{~att_offset[7]}},
att_clamped = att_offset[8] ? att_clamp_value : att_offset[7:0];
always @(posedge gclk)
att_data_out <= att_clamped;
endmodule // strgba