/******************************************************************************/ 
/*                                                                            */ 
/* Copyright (c) 1999 Sun Microsystems, Inc. All rights reserved.             */ 
/*                                                                            */ 
/* The contents of this file are subject to the current version of the Sun    */ 
/* Community Source License, microSPARCII ("the License"). You may not use    */ 
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/* these intellectual property rights may include one or more U.S. patents,   */ 
/* foreign patents, or pending applications.                                  */ 
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/******************************************************************************/ 
/***************************************************************************
****************************************************************************
***
***  Program File:  @(#)column3.v
***
****************************************************************************
****************************************************************************/

//  @(#)column3.v	1.1  4/8/92
//
// **************************************************************
//  column3 -- 4 to 2 compression for column 3.
// **************************************************************


module column3     (
		    sum,		// compressed sum
		    carry,		// compressed carry
		    cout1,		// non-ripple carry-out
		    cout2,		// ripple carry-out
		    cin1,		// non-ripple carry-in
		    cin2,		// ripple carry-in
		    x,			// multiplicand
		    y,			// multiplier
		    pass,		// pass = {0,1}
		    fbs,		// feedback sum
		    fbc			// feedback carry
		    );
	//prop CELLCLASS "MODULE"
	//prop GENERATOR "DataPath"
	//prop TERMPLACE "BIT"

    supply0 GND;
	//prop NETTYPE "GROUND"

    output sum;
	//prop TERMPLACE "BOT"
    output carry;
	//prop TERMPLACE "BOT"
    output [1:0] cout1;
	//prop TERMPLACE "LEFT"
    output cout2;
	//prop TERMPLACE "LEFT"
    input  [1:0] cin1;
	//prop TERMPLACE "RIGHT"
    input  cin2;
	//prop TERMPLACE "RIGHT"
    input  [27:24] x;
	//prop TERMPLACE "TOP"
    input  [3:0] y;
	//prop TERMPLACE "LEFT"
    input pass;
	//prop TERMPLACE "LEFT"
    input fbs;
	//prop TERMPLACE "BOT"
    input fbc;
	//prop TERMPLACE "BOT"

    wire  [5:0] p;		// partial products
    wire  [1:0] cin1;
    wire  cin2;
    wire  s;			// internal sum's
    wire  pass;
    wire  fbs;
    wire  fbc;

    pproduct_4 pA (
	    p[3:0],
	    x[27:24],
	    y[3:0]
	    );
	    //prop TERMPLACE "POS=0"
	       
    add4 aA (
	    s,
	    cout2,
	    cout1[0],
	    p[0],
	    p[1],
	    p[2],
	    p[3],
	    cin1[0]
	    );
	    //prop TERMPLACE "POS=1"

    pproduct23 pB (
	    p[5:4],
	    pass,
	    fbs,
	    fbc
	    );
	    //prop TERMPLACE "POS=2"

    add4 aB (
	    sum,
	    carry,
	    cout1[1],
	    p[4],
	    p[5],
	    s,
	    cin2,
	    cin1[1]
	    );
	    //prop TERMPLACE "POS=3"

endmodule