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//////////////////////////////////////////////////////////////////////
////                                                              ////
////  OR1200's generate PC                                        ////
////                                                              ////
////  This file is part of the OpenRISC 1200 project              ////
////  http://www.opencores.org/cores/or1k/                        ////
////                                                              ////
////  Description                                                 ////
////  PC, interface to IC.                                        ////
////                                                              ////
////  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 1.4  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 1.3  2002/01/18 07:56:00  lampret
// No more low/high priority interrupts (PICPR removed). Added tick timer exception. Added exception prefix (SR[EPH]). Fixed single-step bug whenreading NPC.
//
// 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 1.10  2001/11/20 18:46:15  simons
// Break point bug fixed
//
// Revision 1.9  2001/11/18 09:58:28  lampret
// Fixed some l.trap typos.
//
// Revision 1.8  2001/11/18 08:36:28  lampret
// For GDB changed single stepping and disabled trap exception.
//
// Revision 1.7  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 dc.v and ic.v. Fixed CR+LF.
//
// Revision 1.6  2001/10/14 13:12:09  lampret
// MP3 version.
//
// Revision 1.1.1.1  2001/10/06 10:18:36  igorm
// no message
//
// Revision 1.1  2001/08/09 13:39:33  lampret
// Major clean-up.
//
//
 
// synopsys translate_off
`include "timescale.v"
// synopsys translate_on
`include "or1200_defines.v"
 
module or1200_genpc(
        // Clock and reset
        clk, rst,
 
        // External i/f to IC
        icpu_adr_o, icpu_cycstb_o, icpu_sel_o, icpu_tag_o,
        icpu_ack_i, icpu_rty_i, icpu_err_i, icpu_adr_i,
 
        // Internal i/f
        branch_op, except_type, except_prefix,
        branch_addrofs, lr_restor, flag, taken, except_start,
        binsn_addr, epcr, spr_dat_i, spr_pc_we, genpc_refetch,
        genpc_freeze, flushpipe, no_more_dslot
);
 
//
// I/O
//
 
//
// Clock and reset
//
input                           clk;
input                           rst;
 
//
// External i/f to IC
//
output  [31:0]                   icpu_adr_o;
output                          icpu_cycstb_o;
output  [3:0]                    icpu_sel_o;
output  [3:0]                    icpu_tag_o;
input                           icpu_ack_i;
input                           icpu_rty_i;
input                           icpu_err_i;
input   [31:0]                   icpu_adr_i;
 
//
// Internal i/f
//
input   [`OR1200_BRANCHOP_WIDTH-1:0]     branch_op;
input   [`OR1200_EXCEPT_WIDTH-1:0]       except_type;
input                                   except_prefix;
input   [31:2]                  branch_addrofs;
input   [31:0]                   lr_restor;
input                           flag;
output                          taken;
input                           except_start;
input   [31:2]                  binsn_addr;
input   [31:0]                   epcr;
input   [31:0]                   spr_dat_i;
input                           spr_pc_we;
input                           genpc_refetch;
input                           genpc_freeze;
input                           flushpipe;
input                           no_more_dslot;
 
//
// Internal wires and regs
//
reg     [31:2]                  pcreg;
reg     [31:0]                   pc;
reg                             taken;  /* Set to in case of jump or taken branch */
reg                             dslot;  /* set when fetching delay slot insn */
reg                             btarget; /* set when fetching branch target insns */
 
//
// Address of insn to be fecthed
//
assign icpu_adr_o = !no_more_dslot & !except_start & !spr_pc_we & (icpu_rty_i | genpc_refetch) ? icpu_adr_i : pc;
// assign icpu_adr_o = !except_start & !spr_pc_we & (icpu_rty_i | genpc_refetch) ? icpu_adr_i : pc;
 
//
// Control access to IC subsystem
//
// assign icpu_cycstb_o = !genpc_freeze & !no_more_dslot;
assign icpu_cycstb_o = !genpc_freeze;
assign icpu_sel_o = 4'b1111;
assign icpu_tag_o = `OR1200_ITAG_NI;
 
//
// Async calculation of new PC value. This value is used for addressing the IC.
//
always @(pcreg or branch_addrofs or binsn_addr or flag or branch_op or except_type
        or except_start or lr_restor or epcr or spr_pc_we or spr_dat_i or except_prefix) begin
        casex ({spr_pc_we, except_start, branch_op})    // synopsys parallel_case
                {2'b00, `OR1200_BRANCHOP_NOP}: begin
                        pc = {pcreg + 'd1, 2'b0};
                        taken = 1'b0;
                end
                {2'b00, `OR1200_BRANCHOP_J}: begin
`ifdef OR1200_VERBOSE
// synopsys translate_off
                        $display("%t: BRANCHOP_J: pc <= branch_addrofs %h", $time, branch_addrofs);
// synopsys translate_on
`endif
                        pc = {branch_addrofs, 2'b0};
                        taken = 1'b1;
                end
                {2'b00, `OR1200_BRANCHOP_JR}: begin
`ifdef OR1200_VERBOSE
// synopsys translate_off
                        $display("%t: BRANCHOP_JR: pc <= lr_restor %h", $time, lr_restor);
// synopsys translate_on
`endif
                        pc = lr_restor;
                        taken = 1'b1;
                end
                {2'b00, `OR1200_BRANCHOP_BAL}: begin
`ifdef OR1200_VERBOSE
// synopsys translate_off
                        $display("%t: BRANCHOP_BAL: pc %h = binsn_addr %h + branch_addrofs %h", $time, binsn_addr + branch_addrofs, binsn_addr, branch_addrofs);
// synopsys translate_on
`endif
                        pc = {binsn_addr + branch_addrofs, 2'b0};
                        taken = 1'b1;
                end
                {2'b00, `OR1200_BRANCHOP_BF}:
                        if (flag) begin
`ifdef OR1200_VERBOSE
// synopsys translate_off
                                $display("%t: BRANCHOP_BF: pc %h = binsn_addr %h + branch_addrofs %h", $time, binsn_addr + branch_addrofs, binsn_addr, branch_addrofs);
// synopsys translate_on
`endif
                                pc = {binsn_addr + branch_addrofs, 2'b0};
                                taken = 1'b1;
                        end
                        else begin
`ifdef OR1200_VERBOSE
// synopsys translate_off
                                $display("%t: BRANCHOP_BF: not taken", $time);
// synopsys translate_on
`endif
                                pc = {pcreg + 'd1, 2'b0};
                                taken = 1'b0;
                        end
                {2'b00, `OR1200_BRANCHOP_BNF}:
                        if (flag) begin
                                pc = {pcreg + 'd1, 2'b0};
`ifdef OR1200_VERBOSE
// synopsys translate_off
                                $display("%t: BRANCHOP_BNF: not taken", $time);
// synopsys translate_on
`endif
                                taken = 1'b0;
                        end
                        else begin
`ifdef OR1200_VERBOSE
// synopsys translate_off
                                $display("%t: BRANCHOP_BNF: pc %h = binsn_addr %h + branch_addrofs %h", $time, binsn_addr + branch_addrofs, binsn_addr, branch_addrofs);
// synopsys translate_on
`endif
                                pc = {binsn_addr + branch_addrofs, 2'b0};
                                taken = 1'b1;
                        end
                {2'b00, `OR1200_BRANCHOP_RFE}: begin
`ifdef OR1200_VERBOSE
// synopsys translate_off
                        $display("%t: BRANCHOP_RFE: pc <= epcr %h", $time, epcr);
// synopsys translate_on
`endif
                        pc = epcr;
                        taken = 1'b1;
                end
                {2'b01, 3'bxxx}: begin
`ifdef OR1200_VERBOSE
// synopsys translate_off
                        $display("Starting exception: %h.", except_type);
// synopsys translate_on
`endif
                        pc = { {4{except_prefix}}, 16'h0000, except_type, 8'h00};
                        taken = 1'b1;
                end
                default: begin
`ifdef OR1200_VERBOSE
// synopsys translate_off
                        $display("l.mtspr writing into PC: %h.", spr_dat_i);
// synopsys translate_on
`endif
                        pc = spr_dat_i;
                        taken = 1'b0;
                end
        endcase
end
 
//
// PC register
//
always @(posedge clk or posedge rst)
        if (rst)
                pcreg <= #1 30'd63;
        else if (spr_pc_we)
                pcreg <= #1 spr_dat_i[31:2];
        else if (no_more_dslot | except_start | !genpc_freeze & !icpu_rty_i & !genpc_refetch)
//      else if (except_start | !genpc_freeze & !icpu_rty_i & !genpc_refetch)
                pcreg <= #1 pc[31:2];
 
endmodule

Line No.	Rev	Author	Line
1	504	lampret	`//////////////////////////////////////////////////////////////////////`
2			`//// ////`
3			`//// OR1200's generate PC ////`
4			`//// ////`
5			`//// This file is part of the OpenRISC 1200 project ////`
6			`//// http://www.opencores.org/cores/or1k/ ////`
7			`//// ////`
8			`//// Description ////`
9			`//// PC, interface to IC. ////`
10			`//// ////`
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	660	lampret	`// Revision 1.4 2002/01/28 01:16:00 lampret`
48			`// 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.`
49			`//`
50	617	lampret	`// Revision 1.3 2002/01/18 07:56:00 lampret`
51			`// No more low/high priority interrupts (PICPR removed). Added tick timer exception. Added exception prefix (SR[EPH]). Fixed single-step bug whenreading NPC.`
52			`//`
53	589	lampret	`// Revision 1.2 2002/01/14 06:18:22 lampret`
54			`// Fixed mem2reg bug in FAST implementation. Updated debug unit to work with new genpc/if.`
55			`//`
56	562	lampret	`// Revision 1.1 2002/01/03 08:16:15 lampret`
57			`// New prefixes for RTL files, prefixed module names. Updated cache controllers and MMUs.`
58			`//`
59	504	lampret	`// Revision 1.10 2001/11/20 18:46:15 simons`
60			`// Break point bug fixed`
61			`//`
62			`// Revision 1.9 2001/11/18 09:58:28 lampret`
63			`// Fixed some l.trap typos.`
64			`//`
65			`// Revision 1.8 2001/11/18 08:36:28 lampret`
66			`// For GDB changed single stepping and disabled trap exception.`
67			`//`
68			`// Revision 1.7 2001/10/21 17:57:16 lampret`
69			`// Removed params from generic_XX.v. Added translate_off/on in sprs.v and id.v. Removed spr_addr from dc.v and ic.v. Fixed CR+LF.`
70			`//`
71			`// Revision 1.6 2001/10/14 13:12:09 lampret`
72			`// MP3 version.`
73			`//`
74			`// Revision 1.1.1.1 2001/10/06 10:18:36 igorm`
75			`// no message`
76			`//`
77			`// Revision 1.1 2001/08/09 13:39:33 lampret`
78			`// Major clean-up.`
79			`//`
80			`//`
81
82			`// synopsys translate_off`
83			`include "timescale.v"
84			`// synopsys translate_on`
85			`include "or1200_defines.v"
86
87			`module or1200_genpc(`
88			`// Clock and reset`
89			`clk, rst,`
90
91			`// External i/f to IC`
92	660	lampret	`icpu_adr_o, icpu_cycstb_o, icpu_sel_o, icpu_tag_o,`
93	504	lampret	`icpu_ack_i, icpu_rty_i, icpu_err_i, icpu_adr_i,`
94
95			`// Internal i/f`
96	589	lampret	`branch_op, except_type, except_prefix,`
97	504	lampret	`branch_addrofs, lr_restor, flag, taken, except_start,`
98	562	lampret	`binsn_addr, epcr, spr_dat_i, spr_pc_we, genpc_refetch,`
99	617	lampret	`genpc_freeze, flushpipe, no_more_dslot`
100	504	lampret	`);`
101
102			`//`
103			`// I/O`
104			`//`
105
106			`//`
107			`// Clock and reset`
108			`//`
109			`input clk;`
110			`input rst;`
111
112			`//`
113			`// External i/f to IC`
114			`//`
115			`output [31:0] icpu_adr_o;`
116	660	lampret	`output icpu_cycstb_o;`
117	504	lampret	`output [3:0] icpu_sel_o;`
118			`output [3:0] icpu_tag_o;`
119			`input icpu_ack_i;`
120			`input icpu_rty_i;`
121			`input icpu_err_i;`
122			`input [31:0] icpu_adr_i;`
123
124			`//`
125			`// Internal i/f`
126			`//`
127			input [`OR1200_BRANCHOP_WIDTH-1:0] branch_op;
128			input [`OR1200_EXCEPT_WIDTH-1:0] except_type;
129	589	lampret	`input except_prefix;`
130	504	lampret	`input [31:2] branch_addrofs;`
131			`input [31:0] lr_restor;`
132			`input flag;`
133			`output taken;`
134			`input except_start;`
135			`input [31:2] binsn_addr;`
136			`input [31:0] epcr;`
137			`input [31:0] spr_dat_i;`
138			`input spr_pc_we;`
139			`input genpc_refetch;`
140	562	lampret	`input genpc_freeze;`
141			`input flushpipe;`
142	617	lampret	`input no_more_dslot;`
143	504	lampret
144			`//`
145			`// Internal wires and regs`
146			`//`
147			`reg [31:2] pcreg;`
148			`reg [31:0] pc;`
149			`reg taken; /* Set to in case of jump or taken branch */`
150			`reg dslot; /* set when fetching delay slot insn */`
151			`reg btarget; /* set when fetching branch target insns */`
152
153			`//`
154			`// Address of insn to be fecthed`
155			`//`
156	617	lampret	`assign icpu_adr_o = !no_more_dslot & !except_start & !spr_pc_we & (icpu_rty_i \| genpc_refetch) ? icpu_adr_i : pc;`
157			`// assign icpu_adr_o = !except_start & !spr_pc_we & (icpu_rty_i \| genpc_refetch) ? icpu_adr_i : pc;`
158	504	lampret
159			`//`
160			`// Control access to IC subsystem`
161			`//`
162	660	lampret	`// assign icpu_cycstb_o = !genpc_freeze & !no_more_dslot;`
163			`assign icpu_cycstb_o = !genpc_freeze;`
164	504	lampret	`assign icpu_sel_o = 4'b1111;`
165			assign icpu_tag_o = `OR1200_ITAG_NI;
166
167			`//`
168			`// Async calculation of new PC value. This value is used for addressing the IC.`
169			`//`
170			`always @(pcreg or branch_addrofs or binsn_addr or flag or branch_op or except_type`
171	589	lampret	`or except_start or lr_restor or epcr or spr_pc_we or spr_dat_i or except_prefix) begin`
172	504	lampret	`casex ({spr_pc_we, except_start, branch_op}) // synopsys parallel_case`
173			{2'b00, `OR1200_BRANCHOP_NOP}: begin
174			`pc = {pcreg + 'd1, 2'b0};`
175			`taken = 1'b0;`
176			`end`
177			{2'b00, `OR1200_BRANCHOP_J}: begin
178			`ifdef OR1200_VERBOSE
179			`// synopsys translate_off`
180			`$display("%t: BRANCHOP_J: pc <= branch_addrofs %h", $time, branch_addrofs);`
181			`// synopsys translate_on`
182			`endif
183			`pc = {branch_addrofs, 2'b0};`
184			`taken = 1'b1;`
185			`end`
186			{2'b00, `OR1200_BRANCHOP_JR}: begin
187			`ifdef OR1200_VERBOSE
188			`// synopsys translate_off`
189			`$display("%t: BRANCHOP_JR: pc <= lr_restor %h", $time, lr_restor);`
190			`// synopsys translate_on`
191			`endif
192			`pc = lr_restor;`
193			`taken = 1'b1;`
194			`end`
195			{2'b00, `OR1200_BRANCHOP_BAL}: begin
196			`ifdef OR1200_VERBOSE
197			`// synopsys translate_off`
198			`$display("%t: BRANCHOP_BAL: pc %h = binsn_addr %h + branch_addrofs %h", $time, binsn_addr + branch_addrofs, binsn_addr, branch_addrofs);`
199			`// synopsys translate_on`
200			`endif
201			`pc = {binsn_addr + branch_addrofs, 2'b0};`
202			`taken = 1'b1;`
203			`end`
204			{2'b00, `OR1200_BRANCHOP_BF}:
205			`if (flag) begin`
206			`ifdef OR1200_VERBOSE
207			`// synopsys translate_off`
208			`$display("%t: BRANCHOP_BF: pc %h = binsn_addr %h + branch_addrofs %h", $time, binsn_addr + branch_addrofs, binsn_addr, branch_addrofs);`
209			`// synopsys translate_on`
210			`endif
211			`pc = {binsn_addr + branch_addrofs, 2'b0};`
212			`taken = 1'b1;`
213			`end`
214			`else begin`
215			`ifdef OR1200_VERBOSE
216			`// synopsys translate_off`
217			`$display("%t: BRANCHOP_BF: not taken", $time);`
218			`// synopsys translate_on`
219			`endif
220			`pc = {pcreg + 'd1, 2'b0};`
221			`taken = 1'b0;`
222			`end`
223			{2'b00, `OR1200_BRANCHOP_BNF}:
224			`if (flag) begin`
225			`pc = {pcreg + 'd1, 2'b0};`
226			`ifdef OR1200_VERBOSE
227			`// synopsys translate_off`
228			`$display("%t: BRANCHOP_BNF: not taken", $time);`
229			`// synopsys translate_on`
230			`endif
231			`taken = 1'b0;`
232			`end`
233			`else begin`
234			`ifdef OR1200_VERBOSE
235			`// synopsys translate_off`
236			`$display("%t: BRANCHOP_BNF: pc %h = binsn_addr %h + branch_addrofs %h", $time, binsn_addr + branch_addrofs, binsn_addr, branch_addrofs);`
237			`// synopsys translate_on`
238			`endif
239			`pc = {binsn_addr + branch_addrofs, 2'b0};`
240			`taken = 1'b1;`
241			`end`
242			{2'b00, `OR1200_BRANCHOP_RFE}: begin
243			`ifdef OR1200_VERBOSE
244			`// synopsys translate_off`
245			`$display("%t: BRANCHOP_RFE: pc <= epcr %h", $time, epcr);`
246			`// synopsys translate_on`
247			`endif
248			`pc = epcr;`
249			`taken = 1'b1;`
250			`end`
251			`{2'b01, 3'bxxx}: begin`
252			`ifdef OR1200_VERBOSE
253			`// synopsys translate_off`
254			`$display("Starting exception: %h.", except_type);`
255			`// synopsys translate_on`
256			`endif
257	589	lampret	`pc = { {4{except_prefix}}, 16'h0000, except_type, 8'h00};`
258	504	lampret	`taken = 1'b1;`
259			`end`
260			`default: begin`
261			`ifdef OR1200_VERBOSE
262			`// synopsys translate_off`
263			`$display("l.mtspr writing into PC: %h.", spr_dat_i);`
264			`// synopsys translate_on`
265			`endif
266			`pc = spr_dat_i;`
267			`taken = 1'b0;`
268			`end`
269			`endcase`
270			`end`
271
272			`//`
273			`// PC register`
274			`//`
275			`always @(posedge clk or posedge rst)`
276			`if (rst)`
277			`pcreg <= #1 30'd63;`
278			`else if (spr_pc_we)`
279			`pcreg <= #1 spr_dat_i[31:2];`
280	617	lampret	`else if (no_more_dslot \| except_start \| !genpc_freeze & !icpu_rty_i & !genpc_refetch)`
281			`// else if (except_start \| !genpc_freeze & !icpu_rty_i & !genpc_refetch)`
282	504	lampret	`pcreg <= #1 pc[31:2];`
283
284			`endmodule`

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