////////////////////////////////////////////////////////////////////// //// //// //// 8051 compare //// //// //// //// This file is part of the 8051 cores project //// //// http://www.opencores.org/cores/8051/ //// //// //// //// Description //// //// compares selected inputs and set eq to 1 if they are equal //// //// Is used for conditional jumps. //// //// //// //// To Do: //// //// replace CSS_AZ with CSS_DES //// //// //// //// Author(s): //// //// - Simon Teran, simont@opencores.org //// //// //// ////////////////////////////////////////////////////////////////////// //// //// //// Copyright (C) 2000 Authors and OPENCORES.ORG //// //// //// //// This source file may be used and distributed without //// //// restriction provided that this copyright statement is not //// //// removed from the file and that any derivative work contains //// //// the original copyright notice and the associated disclaimer. //// //// //// //// This source file is free software; you can redistribute it //// //// and/or modify it under the terms of the GNU Lesser General //// //// Public License as published by the Free Software Foundation; //// //// either version 2.1 of the License, or (at your option) any //// //// later version. //// //// //// //// This source 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 Lesser General Public License for more //// //// details. //// //// //// //// You should have received a copy of the GNU Lesser General //// //// Public License along with this source; if not, download it //// //// from http://www.opencores.org/lgpl.shtml //// //// //// ////////////////////////////////////////////////////////////////////// // // CVS Revision History // // $Log: oc8051_comp.v,v $ // Revision 1.8 2003/07/01 20:47:38 simont // add /* synopsys xx_case */ to case statments. // // Revision 1.7 2003/04/25 17:15:51 simont // change branch instruction execution (reduse needed clock periods). // // Revision 1.6 2003/04/02 11:26:21 simont // updating... // // Revision 1.5 2002/09/30 17:33:59 simont // prepared header // // // synopsys translate_off `include "oc8051_timescale.v" // synopsys translate_on `include "oc8051_defines.v" module oc8051_comp (sel, b_in, cy, acc, des, /*comp_wait, */eq); // // sel (in) select whithc sourses to compare (look defines.v) [oc8051_decoder.comp_sel] // b_in (in) bit in - output from bit addressable memory space [oc8051_ram_sel.bit_out] // cy (in) carry flag [oc8051_psw.data_out[7] ] // acc (in) accumulator [oc8051_acc.data_out] // ram (in) input from ram [oc8051_ram_sel.out_data] // op2 (in) immediate data [oc8051_op_select.op2_out -r] // des (in) destination from alu [oc8051_alu.des1 -r] // eq (out) if (src1 == src2) eq = 1 [oc8051_decoder.eq] // input [1:0] sel; input b_in, cy/*, comp_wait*/; input [7:0] acc, des; output eq; reg eq_r; assign eq = eq_r;// & comp_wait; always @(sel or b_in or cy or acc or des) begin case (sel) /* synopsys full_case parallel_case */ `OC8051_CSS_AZ : eq_r = (acc == 8'h00); `OC8051_CSS_DES : eq_r = (des == 8'h00); `OC8051_CSS_CY : eq_r = cy; `OC8051_CSS_BIT : eq_r = b_in; endcase end endmodule
