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1 | // ========== Copyright Header Begin ========================================== |
2 | // | |
3 | // OpenSPARC T2 Processor File: niu_smx_req_sii_cr.v | |
4 | // Copyright (C) 1995-2007 Sun Microsystems, Inc. All Rights Reserved | |
5 | // 4150 Network Circle, Santa Clara, California 95054, U.S.A. | |
6 | // | |
7 | // * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. | |
8 | // | |
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 | |
11 | // the Free Software Foundation; version 2 of the License. | |
12 | // | |
13 | // This program is distributed in the hope that it will be useful, | |
14 | // but WITHOUT ANY WARRANTY; without even the implied warranty of | |
15 | // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
16 | // GNU General Public License for more details. | |
17 | // | |
18 | // You should have received a copy of the GNU General Public License | |
19 | // along with this program; if not, write to the Free Software | |
20 | // Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA | |
21 | // | |
22 | // For the avoidance of doubt, and except that if any non-GPL license | |
23 | // choice is available it will apply instead, Sun elects to use only | |
24 | // the General Public License version 2 (GPLv2) at this time for any | |
25 | // software where a choice of GPL license versions is made | |
26 | // available with the language indicating that GPLv2 or any later version | |
27 | // may be used, or where a choice of which version of the GPL is applied is | |
28 | // otherwise unspecified. | |
29 | // | |
30 | // Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, | |
31 | // CA 95054 USA or visit www.sun.com if you need additional information or | |
32 | // have any questions. | |
33 | // | |
34 | // ========== Copyright Header End ============================================ | |
35 | ||
36 | module niu_smx_req_sii_cr( | |
37 | /*AUTOARG*/ | |
38 | // Outputs | |
39 | ocr_avail, bcr_avail, | |
40 | // Inputs | |
41 | clk, reset_l, | |
42 | sii_niu_oqdq, sii_niu_bqdq, o_enq, b_enq | |
43 | ); | |
44 | ||
45 | input clk; | |
46 | input reset_l; | |
47 | ||
48 | // sii if | |
49 | input sii_niu_oqdq; | |
50 | input sii_niu_bqdq; | |
51 | ||
52 | // arb if | |
53 | input o_enq; | |
54 | input b_enq; | |
55 | output ocr_avail; | |
56 | output bcr_avail; | |
57 | ||
58 | ||
59 | reg [4:0] order_cr; | |
60 | reg [4:0] bypass_cr; | |
61 | ||
62 | reg sii_niu_oqdq_r, sii_niu_bqdq_r; | |
63 | always @(posedge clk) begin | |
64 | if(!reset_l) begin | |
65 | sii_niu_oqdq_r<= `SMX_PD 1'b0; | |
66 | sii_niu_bqdq_r<= `SMX_PD 1'b0; | |
67 | end | |
68 | else begin | |
69 | sii_niu_oqdq_r<= `SMX_PD sii_niu_oqdq; | |
70 | sii_niu_bqdq_r<= `SMX_PD sii_niu_bqdq; | |
71 | end | |
72 | end | |
73 | ||
74 | wire o_deq= sii_niu_oqdq_r; | |
75 | wire b_deq= sii_niu_bqdq_r; | |
76 | ||
77 | wire inc_ocr_n= o_deq & ~o_enq; | |
78 | wire dec_ocr_n= ~o_deq & o_enq; | |
79 | ||
80 | wire inc_bcr_n= b_deq & ~b_enq; | |
81 | wire dec_bcr_n= ~b_deq & b_enq; | |
82 | ||
83 | ||
84 | // clamp cr in case over | |
85 | wire [4:0] inc_order_cr_n= (order_cr==`SMX_SII_MAX_ORD_CR)? `SMX_SII_MAX_ORD_CR : | |
86 | order_cr + 1'b1; | |
87 | wire [4:0] dec_order_cr_n= (order_cr==5'h0)? 5'h0 : order_cr - 1'b1; | |
88 | ||
89 | wire [4:0] inc_bypass_cr_n= (bypass_cr==`SMX_SII_MAX_BYP_CR)? `SMX_SII_MAX_BYP_CR : | |
90 | bypass_cr + 1'b1; | |
91 | wire [4:0] dec_bypass_cr_n= (bypass_cr==5'h0)? 5'h0 : bypass_cr - 1'b1; | |
92 | ||
93 | always @(posedge clk) begin | |
94 | if(!reset_l) begin | |
95 | order_cr<= `SMX_PD `SMX_SII_MAX_ORD_CR; | |
96 | bypass_cr<= `SMX_PD `SMX_SII_MAX_BYP_CR; | |
97 | end | |
98 | else begin | |
99 | if(inc_ocr_n) order_cr<= `SMX_PD inc_order_cr_n; | |
100 | else if(dec_ocr_n) order_cr<= `SMX_PD dec_order_cr_n; | |
101 | if(inc_bcr_n) bypass_cr<= `SMX_PD inc_bypass_cr_n; | |
102 | else if(dec_bcr_n) bypass_cr<= `SMX_PD dec_bypass_cr_n; | |
103 | end | |
104 | end | |
105 | ||
106 | wire ocr_avail= |order_cr; | |
107 | wire bcr_avail= |bypass_cr; | |
108 | ||
109 | endmodule | |
110 | ||
111 | ||
112 |