// $Header: /devl/xcs/repo/env/Databases/CAEInterfaces/verunilibs/data/rainier/CARRY4.v,v 1.5 2007/06/01 00:24:45 yanx Exp $///////////////////////////////////////////////////////////////////////////////// Copyright (c) 1995/2004 Xilinx, Inc.// All Right Reserved./////////////////////////////////////////////////////////////////////////////////   ____  ____//  /   /\/   /// /___/  \  /    Vendor : Xilinx// \   \   \/     Version : 10.1//  \   \         Description : Xilinx Functional Simulation Library Component//  /   /                  Fast Carry Logic with Look Ahead // /___/   /\     Filename : CARRY4.v// \   \  /  \    Timestamp : Thu Mar 25 16:42:55 PST 2004//  \___\/\___\//// Revision://    04/11/05 - Initial version.//    05/06/05 - Unused CYINT or CI pin need grounded instead of open (CR207752)//    05/31/05 - Change pin order, remove connection check for CYINIT and CI.//    05/30/07 - Change timescale to 1 ps / 1ps.// End Revision`timescale  1 ps / 1 psmodule CARRY4 (CO, O, CI, CYINIT, DI, S);    output [3:0] CO;    output [3:0] O;    input        CI;    input        CYINIT;    input  [3:0] DI;    input  [3:0] S;    wire ci_or_cyinit;//    initial//       ci_or_cyinit = 0;    assign O = S ^ {CO[2:0], ci_or_cyinit};    assign CO[0] = S[0] ? ci_or_cyinit : DI[0];    assign CO[1] = S[1] ? CO[0] : DI[1];    assign CO[2] = S[2] ? CO[1] : DI[2];    assign CO[3] = S[3] ? CO[2] : DI[3];    assign ci_or_cyinit = CYINIT | CI;//    always @(CYINIT or CI)//      if (CYINIT === 1'bz || CYINIT === 1'bx) begin//           $display("Error: CARRY4 instance, %m, detects CYINIT unconnected. Only one of CI and CYINIT inputs can be used and other one need be grounded.");//           $finish;//     end//      else if (CI=== 1'bz || CI=== 1'bx) begin//           $display("Error: CARRY4 instance, %m, detects CI unconnected. Only one of CI and CYINIT inputs can be used and other one need be grounded.");//           $finish;//     end//      else //           ci_or_cyinit = CYINIT | CI;endmodule