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//////////////////////////////////////////////////////////////////////
////                                                              ////
////  OR1200's IC FSM                                             ////
////                                                              ////
////  This file is part of the OpenRISC 1200 project              ////
////  http://www.opencores.org/cores/or1k/                        ////
////                                                              ////
////  Description                                                 ////
////  Insn cache state machine                                    ////
////                                                              ////
////  To Do:                                                      ////
////   - make it smaller and faster                               ////
////                                                              ////
////  Author(s):                                                  ////
////      - Damjan Lampret, lampret@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: not supported by cvs2svn $
// Revision 1.8  2003/06/06 02:54:47  lampret
// When OR1200_NO_IMMU and OR1200_NO_IC are not both defined or undefined at the same time, results in a IC bug. Fixed.
//
// Revision 1.7  2002/03/29 15:16:55  lampret
// Some of the warnings fixed.
//
// Revision 1.6  2002/03/28 19:10:40  lampret
// Optimized cache controller FSM.
//
// Revision 1.1.1.1  2002/03/21 16:55:45  lampret
// First import of the "new" XESS XSV environment.
//
//
// Revision 1.5  2002/02/11 04:33:17  lampret
// Speed optimizations (removed duplicate _cyc_ and _stb_). Fixed D/IMMU cache-inhibit attr.
//
// Revision 1.4  2002/02/01 19:56:54  lampret
// Fixed combinational loops.
//
// Revision 1.3  2002/01/28 01:16:00  lampret
// Changed 'void' nop-ops instead of insn[0] to use insn[16]. Debug unit stalls the tick timer. Prepared new flag generation for add and and insns. Blocked DC/IC while they are turned off. Fixed I/D MMU SPRs layout except WAYs. TODO: smart IC invalidate, l.j 2 and TLB ways.
//
// Revision 1.2  2002/01/14 06:18:22  lampret
// Fixed mem2reg bug in FAST implementation. Updated debug unit to work with new genpc/if.
//
// Revision 1.1  2002/01/03 08:16:15  lampret
// New prefixes for RTL files, prefixed module names. Updated cache controllers and MMUs.
//
// Revision 1.9  2001/10/21 17:57:16  lampret
// Removed params from generic_XX.v. Added translate_off/on in sprs.v and id.v. Removed spr_addr from ic.v and ic.v. Fixed CR+LF.
//
// Revision 1.8  2001/10/19 23:28:46  lampret
// Fixed some synthesis warnings. Configured with caches and MMUs.
//
// Revision 1.7  2001/10/14 13:12:09  lampret
// MP3 version.
//
// Revision 1.1.1.1  2001/10/06 10:18:35  igorm
// no message
//
// Revision 1.2  2001/08/09 13:39:33  lampret
// Major clean-up.
//
// Revision 1.1  2001/07/20 00:46:03  lampret
// Development version of RTL. Libraries are missing.
//
//
 
// synopsys translate_off
`include "timescale.v"
// synopsys translate_on
`include "or1200_defines.v"
 
`define OR1200_ICFSM_IDLE       2'd0
`define OR1200_ICFSM_CFETCH     2'd1
`define OR1200_ICFSM_LREFILL3   2'd2
`define OR1200_ICFSM_IFETCH     2'd3
 
//
// Data cache FSM for cache line of 16 bytes (4x singleword)
//
 
module or1200_ic_fsm(
        // Clock and reset
        clk, rst,
 
        // Internal i/f to top level IC
        ic_en, icqmem_cycstb_i, icqmem_ci_i,
        tagcomp_miss, biudata_valid, biudata_error, start_addr, saved_addr,
        icram_we, biu_read, first_hit_ack, first_miss_ack, first_miss_err,
        burst, tag_we
);
 
//
// I/O
//
input                           clk;
input                           rst;
input                           ic_en;
input                           icqmem_cycstb_i;
input                           icqmem_ci_i;
input                           tagcomp_miss;
input                           biudata_valid;
input                           biudata_error;
input   [31:0]                   start_addr;
output  [31:0]                   saved_addr;
output  [3:0]                    icram_we;
output                          biu_read;
output                          first_hit_ack;
output                          first_miss_ack;
output                          first_miss_err;
output                          burst;
output                          tag_we;
 
//
// Internal wires and regs
//
reg     [31:0]                   saved_addr_r;
reg     [1:0]                    state;
reg     [2:0]                    cnt;
reg                             hitmiss_eval;
reg                             load;
reg                             cache_inhibit;
 
//
// Generate of ICRAM write enables
//
assign icram_we = {4{biu_read & biudata_valid & !cache_inhibit}};
assign tag_we = biu_read & biudata_valid & !cache_inhibit;
 
//
// BIU read and write
//
assign biu_read = (hitmiss_eval & tagcomp_miss) | (!hitmiss_eval & load);
 
//assign saved_addr = hitmiss_eval ? start_addr : saved_addr_r;
assign saved_addr = saved_addr_r;
 
//
// Assert for cache hit first word ready
// Assert for cache miss first word stored/loaded OK
// Assert for cache miss first word stored/loaded with an error
//
assign first_hit_ack = (state == `OR1200_ICFSM_CFETCH) & hitmiss_eval & !tagcomp_miss & !cache_inhibit & !icqmem_ci_i;
assign first_miss_ack = (state == `OR1200_ICFSM_CFETCH) & biudata_valid;
assign first_miss_err = (state == `OR1200_ICFSM_CFETCH) & biudata_error;
 
//
// Assert burst when doing reload of complete cache line
//
assign burst = (state == `OR1200_ICFSM_CFETCH) & tagcomp_miss & !cache_inhibit
                | (state == `OR1200_ICFSM_LREFILL3);
 
//
// Main IC FSM
//
always @(posedge clk or posedge rst) begin
        if (rst) begin
                state <= #1 `OR1200_ICFSM_IDLE;
                saved_addr_r <= #1 32'b0;
                hitmiss_eval <= #1 1'b0;
                load <= #1 1'b0;
                cnt <= #1 3'b000;
                cache_inhibit <= #1 1'b0;
        end
        else
        case (state)    // synopsys parallel_case
                `OR1200_ICFSM_IDLE :
                        if (ic_en & icqmem_cycstb_i) begin              // fetch
                                state <= #1 `OR1200_ICFSM_CFETCH;
                                saved_addr_r <= #1 start_addr;
                                hitmiss_eval <= #1 1'b1;
                                load <= #1 1'b1;
                                cache_inhibit <= #1 1'b0;
                        end
                        else begin                                                      // idle
                                hitmiss_eval <= #1 1'b0;
                                load <= #1 1'b0;
                                cache_inhibit <= #1 1'b0;
                        end
                `OR1200_ICFSM_CFETCH: begin     // fetch
                        if (icqmem_cycstb_i & icqmem_ci_i)
                                cache_inhibit <= #1 1'b1;
                        if (hitmiss_eval)
                                saved_addr_r[31:13] <= #1 start_addr[31:13];
                        if ((!ic_en) ||
                            (hitmiss_eval & !icqmem_cycstb_i) ||        // fetch aborted (usually caused by IMMU)
                            (biudata_error) ||                                          // fetch terminated with an error
                            (cache_inhibit & biudata_valid)) begin      // fetch from cache-inhibited page
                                state <= #1 `OR1200_ICFSM_IDLE;
                                hitmiss_eval <= #1 1'b0;
                                load <= #1 1'b0;
                                cache_inhibit <= #1 1'b0;
                        end
                        else if (tagcomp_miss & biudata_valid) begin    // fetch missed, finish current external fetch and refill
                                state <= #1 `OR1200_ICFSM_LREFILL3;
                                saved_addr_r[3:2] <= #1 saved_addr_r[3:2] + 1'd1;
                                hitmiss_eval <= #1 1'b0;
                                cnt <= #1 `OR1200_ICLS-2;
                                cache_inhibit <= #1 1'b0;
                        end
                        else if (!tagcomp_miss & !icqmem_ci_i) begin    // fetch hit, finish immediately
                                saved_addr_r <= #1 start_addr;
                                cache_inhibit <= #1 1'b0;
                        end
                        else if (!icqmem_cycstb_i) begin        // fetch aborted (usually caused by exception)
                                state <= #1 `OR1200_ICFSM_IDLE;
                                hitmiss_eval <= #1 1'b0;
                                load <= #1 1'b0;
                                cache_inhibit <= #1 1'b0;
                        end
                        else                                            // fetch in-progress
                                hitmiss_eval <= #1 1'b0;
                end
                `OR1200_ICFSM_LREFILL3 : begin
                        if (biudata_valid && (|cnt)) begin              // refill ack, more fetchs to come
                                cnt <= #1 cnt - 1'd1;
                                saved_addr_r[3:2] <= #1 saved_addr_r[3:2] + 1'd1;
                        end
                        else if (biudata_valid) begin                   // last fetch of line refill
                                state <= #1 `OR1200_ICFSM_IDLE;
                                saved_addr_r <= #1 start_addr;
                                hitmiss_eval <= #1 1'b0;
                                load <= #1 1'b0;
                        end
                end
                default:
                        state <= #1 `OR1200_ICFSM_IDLE;
        endcase
end
 
endmodule

Line No.	Rev	Author	Line
1	504	lampret	`//////////////////////////////////////////////////////////////////////`
2			`//// ////`
3			`//// OR1200's IC FSM ////`
4			`//// ////`
5			`//// This file is part of the OpenRISC 1200 project ////`
6			`//// http://www.opencores.org/cores/or1k/ ////`
7			`//// ////`
8			`//// Description ////`
9	1171	lampret	`//// Insn cache state machine ////`
10	504	lampret	`//// ////`
11			`//// To Do: ////`
12			`//// - make it smaller and faster ////`
13			`//// ////`
14			`//// Author(s): ////`
15			`//// - Damjan Lampret, lampret@opencores.org ////`
16			`//// ////`
17			`//////////////////////////////////////////////////////////////////////`
18			`//// ////`
19			`//// Copyright (C) 2000 Authors and OPENCORES.ORG ////`
20			`//// ////`
21			`//// This source file may be used and distributed without ////`
22			`//// restriction provided that this copyright statement is not ////`
23			`//// removed from the file and that any derivative work contains ////`
24			`//// the original copyright notice and the associated disclaimer. ////`
25			`//// ////`
26			`//// This source file is free software; you can redistribute it ////`
27			`//// and/or modify it under the terms of the GNU Lesser General ////`
28			`//// Public License as published by the Free Software Foundation; ////`
29			`//// either version 2.1 of the License, or (at your option) any ////`
30			`//// later version. ////`
31			`//// ////`
32			`//// This source is distributed in the hope that it will be ////`
33			`//// useful, but WITHOUT ANY WARRANTY; without even the implied ////`
34			`//// warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR ////`
35			`//// PURPOSE. See the GNU Lesser General Public License for more ////`
36			`//// details. ////`
37			`//// ////`
38			`//// You should have received a copy of the GNU Lesser General ////`
39			`//// Public License along with this source; if not, download it ////`
40			`//// from http://www.opencores.org/lgpl.shtml ////`
41			`//// ////`
42			`//////////////////////////////////////////////////////////////////////`
43			`//`
44			`// CVS Revision History`
45			`//`
46			`// $Log: not supported by cvs2svn $`
47	1171	lampret	`// Revision 1.8 2003/06/06 02:54:47 lampret`
48			`// When OR1200_NO_IMMU and OR1200_NO_IC are not both defined or undefined at the same time, results in a IC bug. Fixed.`
49			`//`
50	1161	lampret	`// Revision 1.7 2002/03/29 15:16:55 lampret`
51			`// Some of the warnings fixed.`
52			`//`
53	788	lampret	`// Revision 1.6 2002/03/28 19:10:40 lampret`
54			`// Optimized cache controller FSM.`
55			`//`
56	775	lampret	`// Revision 1.1.1.1 2002/03/21 16:55:45 lampret`
57			`// First import of the "new" XESS XSV environment.`
58			`//`
59			`//`
60			`// Revision 1.5 2002/02/11 04:33:17 lampret`
61			`// Speed optimizations (removed duplicate _cyc_ and _stb_). Fixed D/IMMU cache-inhibit attr.`
62			`//`
63	660	lampret	`// Revision 1.4 2002/02/01 19:56:54 lampret`
64			`// Fixed combinational loops.`
65			`//`
66	636	lampret	`// Revision 1.3 2002/01/28 01:16:00 lampret`
67			`// Changed 'void' nop-ops instead of insn[0] to use insn[16]. Debug unit stalls the tick timer. Prepared new flag generation for add and and insns. Blocked DC/IC while they are turned off. Fixed I/D MMU SPRs layout except WAYs. TODO: smart IC invalidate, l.j 2 and TLB ways.`
68			`//`
69	617	lampret	`// Revision 1.2 2002/01/14 06:18:22 lampret`
70			`// Fixed mem2reg bug in FAST implementation. Updated debug unit to work with new genpc/if.`
71			`//`
72	562	lampret	`// Revision 1.1 2002/01/03 08:16:15 lampret`
73			`// New prefixes for RTL files, prefixed module names. Updated cache controllers and MMUs.`
74			`//`
75	504	lampret	`// Revision 1.9 2001/10/21 17:57:16 lampret`
76			`// Removed params from generic_XX.v. Added translate_off/on in sprs.v and id.v. Removed spr_addr from ic.v and ic.v. Fixed CR+LF.`
77			`//`
78			`// Revision 1.8 2001/10/19 23:28:46 lampret`
79			`// Fixed some synthesis warnings. Configured with caches and MMUs.`
80			`//`
81			`// Revision 1.7 2001/10/14 13:12:09 lampret`
82			`// MP3 version.`
83			`//`
84			`// Revision 1.1.1.1 2001/10/06 10:18:35 igorm`
85			`// no message`
86			`//`
87			`// Revision 1.2 2001/08/09 13:39:33 lampret`
88			`// Major clean-up.`
89			`//`
90			`// Revision 1.1 2001/07/20 00:46:03 lampret`
91			`// Development version of RTL. Libraries are missing.`
92			`//`
93			`//`
94
95			`// synopsys translate_off`
96			`include "timescale.v"
97			`// synopsys translate_on`
98			`include "or1200_defines.v"
99
100	788	lampret	`define OR1200_ICFSM_IDLE 2'd0
101			`define OR1200_ICFSM_CFETCH 2'd1
102			`define OR1200_ICFSM_LREFILL3 2'd2
103			`define OR1200_ICFSM_IFETCH 2'd3
104	504	lampret
105			`//`
106			`// Data cache FSM for cache line of 16 bytes (4x singleword)`
107			`//`
108
109			`module or1200_ic_fsm(`
110			`// Clock and reset`
111			`clk, rst,`
112
113			`// Internal i/f to top level IC`
114	1171	lampret	`ic_en, icqmem_cycstb_i, icqmem_ci_i,`
115	504	lampret	`tagcomp_miss, biudata_valid, biudata_error, start_addr, saved_addr,`
116			`icram_we, biu_read, first_hit_ack, first_miss_ack, first_miss_err,`
117	660	lampret	`burst, tag_we`
118	504	lampret	`);`
119
120			`//`
121			`// I/O`
122			`//`
123			`input clk;`
124			`input rst;`
125			`input ic_en;`
126	1171	lampret	`input icqmem_cycstb_i;`
127			`input icqmem_ci_i;`
128	504	lampret	`input tagcomp_miss;`
129			`input biudata_valid;`
130			`input biudata_error;`
131			`input [31:0] start_addr;`
132			`output [31:0] saved_addr;`
133			`output [3:0] icram_we;`
134			`output biu_read;`
135			`output first_hit_ack;`
136			`output first_miss_ack;`
137			`output first_miss_err;`
138			`output burst;`
139	660	lampret	`output tag_we;`
140	504	lampret
141			`//`
142			`// Internal wires and regs`
143			`//`
144	660	lampret	`reg [31:0] saved_addr_r;`
145	788	lampret	`reg [1:0] state;`
146	504	lampret	`reg [2:0] cnt;`
147			`reg hitmiss_eval;`
148			`reg load;`
149	660	lampret	`reg cache_inhibit;`
150	504	lampret
151			`//`
152			`// Generate of ICRAM write enables`
153			`//`
154	1161	lampret	`assign icram_we = {4{biu_read & biudata_valid & !cache_inhibit}};`
155	660	lampret	`assign tag_we = biu_read & biudata_valid & !cache_inhibit;`
156	504	lampret
157			`//`
158			`// BIU read and write`
159			`//`
160			`assign biu_read = (hitmiss_eval & tagcomp_miss) \| (!hitmiss_eval & load);`
161
162	660	lampret	`//assign saved_addr = hitmiss_eval ? start_addr : saved_addr_r;`
163			`assign saved_addr = saved_addr_r;`
164
165	504	lampret	`//`
166			`// Assert for cache hit first word ready`
167			`// Assert for cache miss first word stored/loaded OK`
168			`// Assert for cache miss first word stored/loaded with an error`
169			`//`
170	1171	lampret	assign first_hit_ack = (state == `OR1200_ICFSM_CFETCH) & hitmiss_eval & !tagcomp_miss & !cache_inhibit & !icqmem_ci_i;
171	660	lampret	assign first_miss_ack = (state == `OR1200_ICFSM_CFETCH) & biudata_valid;
172			assign first_miss_err = (state == `OR1200_ICFSM_CFETCH) & biudata_error;
173	504	lampret
174			`//`
175			`// Assert burst when doing reload of complete cache line`
176			`//`
177	660	lampret	assign burst = (state == `OR1200_ICFSM_CFETCH) & tagcomp_miss & !cache_inhibit
178	504	lampret	\| (state == `OR1200_ICFSM_LREFILL3);
179
180			`//`
181			`// Main IC FSM`
182			`//`
183			`always @(posedge clk or posedge rst) begin`
184			`if (rst) begin`
185			state <= #1 `OR1200_ICFSM_IDLE;
186	660	lampret	`saved_addr_r <= #1 32'b0;`
187	504	lampret	`hitmiss_eval <= #1 1'b0;`
188			`load <= #1 1'b0;`
189			`cnt <= #1 3'b000;`
190	660	lampret	`cache_inhibit <= #1 1'b0;`
191	504	lampret	`end`
192			`else`
193			`case (state) // synopsys parallel_case`
194			`OR1200_ICFSM_IDLE :
195	1171	lampret	`if (ic_en & icqmem_cycstb_i) begin // fetch`
196	636	lampret	state <= #1 `OR1200_ICFSM_CFETCH;
197	660	lampret	`saved_addr_r <= #1 start_addr;`
198	504	lampret	`hitmiss_eval <= #1 1'b1;`
199			`load <= #1 1'b1;`
200	660	lampret	`cache_inhibit <= #1 1'b0;`
201	504	lampret	`end`
202			`else begin // idle`
203			`hitmiss_eval <= #1 1'b0;`
204			`load <= #1 1'b0;`
205	660	lampret	`cache_inhibit <= #1 1'b0;`
206	504	lampret	`end`
207	660	lampret	`OR1200_ICFSM_CFETCH: begin // fetch
208	1171	lampret	`if (icqmem_cycstb_i & icqmem_ci_i)`
209	660	lampret	`cache_inhibit <= #1 1'b1;`
210			`if (hitmiss_eval)`
211			`saved_addr_r[31:13] <= #1 start_addr[31:13];`
212	775	lampret	`if ((!ic_en) \|\|`
213	1171	lampret	`(hitmiss_eval & !icqmem_cycstb_i) \|\| // fetch aborted (usually caused by IMMU)`
214	775	lampret	`(biudata_error) \|\| // fetch terminated with an error`
215			`(cache_inhibit & biudata_valid)) begin // fetch from cache-inhibited page`
216	504	lampret	state <= #1 `OR1200_ICFSM_IDLE;
217			`hitmiss_eval <= #1 1'b0;`
218			`load <= #1 1'b0;`
219	660	lampret	`cache_inhibit <= #1 1'b0;`
220	504	lampret	`end`
221	636	lampret	`else if (tagcomp_miss & biudata_valid) begin // fetch missed, finish current external fetch and refill`
222	504	lampret	state <= #1 `OR1200_ICFSM_LREFILL3;
223	1171	lampret	`saved_addr_r[3:2] <= #1 saved_addr_r[3:2] + 1'd1;`
224	504	lampret	`hitmiss_eval <= #1 1'b0;`
225			cnt <= #1 `OR1200_ICLS-2;
226	660	lampret	`cache_inhibit <= #1 1'b0;`
227	504	lampret	`end`
228	1171	lampret	`else if (!tagcomp_miss & !icqmem_ci_i) begin // fetch hit, finish immediately`
229	660	lampret	`saved_addr_r <= #1 start_addr;`
230			`cache_inhibit <= #1 1'b0;`
231	504	lampret	`end`
232	1171	lampret	`else if (!icqmem_cycstb_i) begin // fetch aborted (usually caused by exception)`
233	562	lampret	state <= #1 `OR1200_ICFSM_IDLE;
234			`hitmiss_eval <= #1 1'b0;`
235			`load <= #1 1'b0;`
236	660	lampret	`cache_inhibit <= #1 1'b0;`
237	562	lampret	`end`
238	636	lampret	`else // fetch in-progress`
239	504	lampret	`hitmiss_eval <= #1 1'b0;`
240	660	lampret	`end`
241	504	lampret	`OR1200_ICFSM_LREFILL3 : begin
242	775	lampret	`if (biudata_valid && (\|cnt)) begin // refill ack, more fetchs to come`
243	1171	lampret	`cnt <= #1 cnt - 1'd1;`
244			`saved_addr_r[3:2] <= #1 saved_addr_r[3:2] + 1'd1;`
245	504	lampret	`end`
246	636	lampret	`else if (biudata_valid) begin // last fetch of line refill`
247	504	lampret	state <= #1 `OR1200_ICFSM_IDLE;
248	660	lampret	`saved_addr_r <= #1 start_addr;`
249	504	lampret	`hitmiss_eval <= #1 1'b0;`
250			`load <= #1 1'b0;`
251			`end`
252			`end`
253			`default:`
254			state <= #1 `OR1200_ICFSM_IDLE;
255			`endcase`
256			`end`
257
258			`endmodule`

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