| 1 | // ========== Copyright Header Begin ========================================== |
| 2 | // |
| 3 | // OpenSPARC T2 Processor File: niu_smx_arb_2c.v |
| 4 | // Copyright (C) 1995-2007 Sun Microsystems, Inc. All Rights Reserved |
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| 9 | // This program is free software; you can redistribute it and/or modify |
| 10 | // it under the terms of the GNU General Public License as published by |
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| 13 | // This program is distributed in the hope that it will be useful, |
| 14 | // but WITHOUT ANY WARRANTY; without even the implied warranty of |
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| 16 | // GNU General Public License for more details. |
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| 34 | // ========== Copyright Header End ============================================ |
| 35 | |
| 36 | module niu_smx_arb_2c( |
| 37 | /*AUTOARG*/ |
| 38 | // Outputs |
| 39 | ack_a, ack_b, selout, |
| 40 | // Inputs |
| 41 | clk, reset_l, req_a, req_b, muxin_a, muxin_b |
| 42 | ); |
| 43 | // arb 2 clients |
| 44 | |
| 45 | |
| 46 | parameter MUX_WIDTH= 6; |
| 47 | |
| 48 | // req needs to go down on nxt cycle after seeing ack |
| 49 | input clk; |
| 50 | input reset_l; |
| 51 | |
| 52 | input req_a; |
| 53 | input req_b; |
| 54 | |
| 55 | input [MUX_WIDTH-1:0] muxin_a; |
| 56 | input [MUX_WIDTH-1:0] muxin_b; |
| 57 | |
| 58 | output ack_a; // pulse |
| 59 | output ack_b; |
| 60 | output [MUX_WIDTH-1:0] selout; |
| 61 | |
| 62 | reg a_first, a_first_n; |
| 63 | reg ack_a, ack_b; |
| 64 | reg [MUX_WIDTH-1:0] selout; |
| 65 | |
| 66 | |
| 67 | always @(posedge clk) begin |
| 68 | if(!reset_l) begin |
| 69 | a_first<= `SMX_PD 1'b0; |
| 70 | end |
| 71 | else begin |
| 72 | a_first<= `SMX_PD a_first_n; |
| 73 | end |
| 74 | end |
| 75 | |
| 76 | always @(/*AUTOSENSE*/a_first or muxin_a or muxin_b or req_a or req_b) begin |
| 77 | case({req_a, req_b}) |
| 78 | 2'b00: begin |
| 79 | ack_a= 1'b0; |
| 80 | ack_b= 1'b0; |
| 81 | a_first_n= a_first; |
| 82 | selout= muxin_a; |
| 83 | end |
| 84 | 2'b01: begin |
| 85 | ack_a= 1'b0; |
| 86 | ack_b= 1'b1; |
| 87 | a_first_n= 1'b1; |
| 88 | selout= muxin_b; |
| 89 | end |
| 90 | 2'b10: begin |
| 91 | ack_a= 1'b1; |
| 92 | ack_b= 1'b0; |
| 93 | a_first_n= 1'b0; |
| 94 | selout= muxin_a; |
| 95 | end |
| 96 | 2'b11: begin |
| 97 | ack_a= a_first; |
| 98 | ack_b= ~a_first; |
| 99 | a_first_n= ~a_first; |
| 100 | selout= (a_first)? muxin_a : muxin_b; |
| 101 | end |
| 102 | default: begin |
| 103 | ack_a= 1'b0; |
| 104 | ack_b= 1'b0; |
| 105 | a_first_n= a_first; |
| 106 | selout= muxin_a; |
| 107 | end |
| 108 | endcase |
| 109 | end |
| 110 | |
| 111 | endmodule |
| 112 | |