source: XOpenSparcT1/trunk/T1-FPU/fpu_cnt_lead0_lvl1.v @ 6

// ========== Copyright Header Begin ==========================================
// 
// OpenSPARC T1 Processor File: fpu_cnt_lead0_lvl1.v
// Copyright (c) 2006 Sun Microsystems, Inc.  All Rights Reserved.
// DO NOT ALTER OR REMOVE COPYRIGHT NOTICES.
// 
// The above named program is free software; you can redistribute it and/or
// modify it under the terms of the GNU General Public
// License version 2 as published by the Free Software Foundation.
// 
// The above named program 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
// General Public License for more details.
// 
// You should have received a copy of the GNU General Public
// License along with this work; if not, write to the Free Software
// Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA.
// 
// ========== Copyright Header End ============================================
///////////////////////////////////////////////////////////////////////////////
//
//      Lowest level of lead 0 counters.  Lead 0 count for 4 bits.
//
///////////////////////////////////////////////////////////////////////////////

module fpu_cnt_lead0_lvl1 (
        din,

        din_3_0_eq_0,
        din_3_2_eq_0,
        lead0_4b_0
);


input [3:0]     din;                    // data for lead 0 count bits[3:0]

output          din_3_0_eq_0;           // data in[3:0] is zero
output          din_3_2_eq_0;           // data in[3:2] is zero
output          lead0_4b_0;             // bit[0] of lead 0 count


wire            din_3_0_eq_0;
wire            din_3_2_eq_0;
wire            lead0_4b_0;


assign din_3_0_eq_0= (!(|din[3:0]));

assign din_3_2_eq_0= (!(|din[3:2]));

assign lead0_4b_0= ((!din_3_2_eq_0) && (!din[3]))
                || (din_3_2_eq_0 && (!din[1]));

endmodule