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[/] [openrisc/] [trunk/] [or1200/] [rtl/] [verilog/] [or1200_rf.v] - Blame information for rev 22

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//////////////////////////////////////////////////////////////////////
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////                                                              ////
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////  OR1200's register file inside CPU                           ////
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////                                                              ////
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////  This file is part of the OpenRISC 1200 project              ////
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////  http://www.opencores.org/cores/or1k/                        ////
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////                                                              ////
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////  Description                                                 ////
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////  Instantiation of register file memories                     ////
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////                                                              ////
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////  To Do:                                                      ////
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////   - make it smaller and faster                               ////
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////                                                              ////
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////  Author(s):                                                  ////
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////      - Damjan Lampret, lampret@opencores.org                 ////
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////                                                              ////
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//////////////////////////////////////////////////////////////////////
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////                                                              ////
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//// Copyright (C) 2000 Authors and OPENCORES.ORG                 ////
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////                                                              ////
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//// This source file may be used and distributed without         ////
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//// restriction provided that this copyright statement is not    ////
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//// removed from the file and that any derivative work contains  ////
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//// the original copyright notice and the associated disclaimer. ////
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////                                                              ////
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//// This source file is free software; you can redistribute it   ////
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//// and/or modify it under the terms of the GNU Lesser General   ////
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//// Public License as published by the Free Software Foundation; ////
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//// either version 2.1 of the License, or (at your option) any   ////
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//// later version.                                               ////
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////                                                              ////
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//// This source is distributed in the hope that it will be       ////
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//// useful, but WITHOUT ANY WARRANTY; without even the implied   ////
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//// warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR      ////
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//// PURPOSE.  See the GNU Lesser General Public License for more ////
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//// details.                                                     ////
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////                                                              ////
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//// You should have received a copy of the GNU Lesser General    ////
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//// Public License along with this source; if not, download it   ////
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//// from http://www.opencores.org/lgpl.shtml                     ////
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////                                                              ////
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//////////////////////////////////////////////////////////////////////
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//
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// CVS Revision History
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//
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// $Log: not supported by cvs2svn $
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// Revision 1.2  2002/06/08 16:19:09  lampret
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// Added generic flip-flop based memory macro instantiation.
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//
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// Revision 1.1  2002/01/03 08:16:15  lampret
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// New prefixes for RTL files, prefixed module names. Updated cache controllers and MMUs.
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//
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// Revision 1.13  2001/11/20 18:46:15  simons
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// Break point bug fixed
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//
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// Revision 1.12  2001/11/13 10:02:21  lampret
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// Added 'setpc'. Renamed some signals (except_flushpipe into flushpipe etc)
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//
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// Revision 1.11  2001/11/12 01:45:40  lampret
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// Moved flag bit into SR. Changed RF enable from constant enable to dynamic enable for read ports.
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//
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// Revision 1.10  2001/11/10 03:43:57  lampret
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// Fixed exceptions.
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//
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// Revision 1.9  2001/10/21 17:57:16  lampret
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// 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.
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//
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// Revision 1.8  2001/10/14 13:12:10  lampret
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// MP3 version.
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//
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// Revision 1.1.1.1  2001/10/06 10:18:36  igorm
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// no message
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//
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// Revision 1.3  2001/08/09 13:39:33  lampret
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// Major clean-up.
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//
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// Revision 1.2  2001/07/22 03:31:54  lampret
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// Fixed RAM's oen bug. Cache bypass under development.
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//
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// Revision 1.1  2001/07/20 00:46:21  lampret
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// Development version of RTL. Libraries are missing.
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//
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//
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// synopsys translate_off
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`include "timescale.v"
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// synopsys translate_on
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`include "or1200_defines.v"
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90
module or1200_rf(
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        // Clock and reset
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        clk, rst,
93
 
94
        // Write i/f
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        supv, wb_freeze, addrw, dataw, we, flushpipe,
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97
        // Read i/f
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        id_freeze, addra, addrb, dataa, datab, rda, rdb,
99
 
100
        // Debug
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        spr_cs, spr_write, spr_addr, spr_dat_i, spr_dat_o
102
);
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104
parameter dw = `OR1200_OPERAND_WIDTH;
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parameter aw = `OR1200_REGFILE_ADDR_WIDTH;
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107
//
108
// I/O
109
//
110
 
111
//
112
// Clock and reset
113
//
114
input                           clk;
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input                           rst;
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117
//
118
// Write i/f
119
//
120
input                           supv;
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input                           wb_freeze;
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input   [aw-1:0]         addrw;
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input   [dw-1:0]         dataw;
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input                           we;
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input                           flushpipe;
126
 
127
//
128
// Read i/f
129
//
130
input                           id_freeze;
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input   [aw-1:0]         addra;
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input   [aw-1:0]         addrb;
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output  [dw-1:0]         dataa;
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output  [dw-1:0]         datab;
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input                           rda;
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input                           rdb;
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138
//
139
// SPR access for debugging purposes
140
//
141
input                           spr_cs;
142
input                           spr_write;
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input   [31:0]                   spr_addr;
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input   [31:0]                   spr_dat_i;
145
output  [31:0]                   spr_dat_o;
146
 
147
//
148
// Internal wires and regs
149
//
150
wire    [dw-1:0]         from_rfa;
151
wire    [dw-1:0]         from_rfb;
152
reg     [dw:0]                   dataa_saved;
153
reg     [dw:0]                   datab_saved;
154
wire    [aw-1:0]         rf_addra;
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wire    [aw-1:0]         rf_addrw;
156
wire    [dw-1:0]         rf_dataw;
157
wire                            rf_we;
158
wire                            spr_valid;
159
wire                            rf_ena;
160
wire                            rf_enb;
161
reg                             rf_we_allow;
162
 
163
//
164
// SPR access is valid when spr_cs is asserted and
165
// SPR address matches GPR addresses
166
//
167
assign spr_valid = spr_cs & (spr_addr[10:5] == `OR1200_SPR_RF);
168
 
169
//
170
// SPR data output is always from RF A
171
//
172
assign spr_dat_o = from_rfa;
173
 
174
//
175
// Operand A comes from RF or from saved A register
176
//
177
assign dataa = (dataa_saved[32]) ? dataa_saved[31:0] : from_rfa;
178
 
179
//
180
// Operand B comes from RF or from saved B register
181
//
182
assign datab = (datab_saved[32]) ? datab_saved[31:0] : from_rfb;
183
 
184
//
185
// RF A read address is either from SPRS or normal from CPU control
186
//
187
assign rf_addra = (spr_valid & !spr_write) ? spr_addr[4:0] : addra;
188
 
189
//
190
// RF write address is either from SPRS or normal from CPU control
191
//
192
assign rf_addrw = (spr_valid & spr_write) ? spr_addr[4:0] : addrw;
193
 
194
//
195
// RF write data is either from SPRS or normal from CPU datapath
196
//
197
assign rf_dataw = (spr_valid & spr_write) ? spr_dat_i : dataw;
198
 
199
//
200
// RF write enable is either from SPRS or normal from CPU control
201
//
202
always @(posedge rst or posedge clk)
203
        if (rst)
204
                rf_we_allow <= #1 1'b1;
205
        else if (~wb_freeze)
206
                rf_we_allow <= #1 ~flushpipe;
207
 
208
assign rf_we = ((spr_valid & spr_write) | (we & ~wb_freeze)) & rf_we_allow & (supv | (|rf_addrw));
209
 
210
//
211
// CS RF A asserted when instruction reads operand A and ID stage
212
// is not stalled
213
//
214
assign rf_ena = rda & ~id_freeze | spr_valid;   // probably works with fixed binutils
215
// assign rf_ena = 1'b1;                        // does not work with single-stepping
216
//assign rf_ena = ~id_freeze | spr_valid;       // works with broken binutils 
217
 
218
//
219
// CS RF B asserted when instruction reads operand B and ID stage
220
// is not stalled
221
//
222
assign rf_enb = rdb & ~id_freeze | spr_valid;
223
// assign rf_enb = 1'b1;
224
//assign rf_enb = ~id_freeze | spr_valid;       // works with broken binutils 
225
 
226
//
227
// Stores operand from RF_A into temp reg when pipeline is frozen
228
//
229
always @(posedge clk or posedge rst)
230
        if (rst) begin
231
                dataa_saved <= #1 33'b0;
232
        end
233
        else if (id_freeze & !dataa_saved[32]) begin
234
                dataa_saved <= #1 {1'b1, from_rfa};
235
        end
236
        else if (!id_freeze)
237
                dataa_saved <= #1 33'b0;
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239
//
240
// Stores operand from RF_B into temp reg when pipeline is frozen
241
//
242
always @(posedge clk or posedge rst)
243
        if (rst) begin
244
                datab_saved <= #1 33'b0;
245
        end
246
        else if (id_freeze & !datab_saved[32]) begin
247
                datab_saved <= #1 {1'b1, from_rfb};
248
        end
249
        else if (!id_freeze)
250
                datab_saved <= #1 33'b0;
251
 
252
`ifdef OR1200_RFRAM_TWOPORT
253
 
254
//
255
// Instantiation of register file two-port RAM A
256
//
257
or1200_tpram_32x32 rf_a(
258
        // Port A
259
        .clk_a(clk),
260
        .rst_a(rst),
261
        .ce_a(rf_ena),
262
        .we_a(1'b0),
263
        .oe_a(1'b1),
264
        .addr_a(rf_addra),
265
        .di_a(32'h0000_0000),
266
        .do_a(from_rfa),
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268
        // Port B
269
        .clk_b(clk),
270
        .rst_b(rst),
271
        .ce_b(rf_we),
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        .we_b(rf_we),
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        .oe_b(1'b0),
274
        .addr_b(rf_addrw),
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        .di_b(rf_dataw),
276
        .do_b()
277
);
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279
//
280
// Instantiation of register file two-port RAM B
281
//
282
or1200_tpram_32x32 rf_b(
283
        // Port A
284
        .clk_a(clk),
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        .rst_a(rst),
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        .ce_a(rf_enb),
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        .we_a(1'b0),
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        .oe_a(1'b1),
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        .addr_a(addrb),
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        .di_a(32'h0000_0000),
291
        .do_a(from_rfb),
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293
        // Port B
294
        .clk_b(clk),
295
        .rst_b(rst),
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        .ce_b(rf_we),
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        .we_b(rf_we),
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        .oe_b(1'b0),
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        .addr_b(rf_addrw),
300
        .di_b(rf_dataw),
301
        .do_b()
302
);
303
 
304
`else
305
 
306
`ifdef OR1200_RFRAM_DUALPORT
307
 
308
//
309
// Instantiation of register file two-port RAM A
310
//
311
or1200_dpram_32x32 rf_a(
312
        // Port A
313
        .clk_a(clk),
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        .rst_a(rst),
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        .ce_a(rf_ena),
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        .oe_a(1'b1),
317
        .addr_a(rf_addra),
318
        .do_a(from_rfa),
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        // Port B
321
        .clk_b(clk),
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        .rst_b(rst),
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        .ce_b(rf_we),
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        .we_b(rf_we),
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        .addr_b(rf_addrw),
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        .di_b(rf_dataw)
327
);
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329
//
330
// Instantiation of register file two-port RAM B
331
//
332
or1200_dpram_32x32 rf_b(
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        // Port A
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        .clk_a(clk),
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        .rst_a(rst),
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        .ce_a(rf_enb),
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        .oe_a(1'b1),
338
        .addr_a(addrb),
339
        .do_a(from_rfb),
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341
        // Port B
342
        .clk_b(clk),
343
        .rst_b(rst),
344
        .ce_b(rf_we),
345
        .we_b(rf_we),
346
        .addr_b(rf_addrw),
347
        .di_b(rf_dataw)
348
);
349
 
350
`else
351
 
352
`ifdef OR1200_RFRAM_GENERIC
353
 
354
//
355
// Instantiation of generic (flip-flop based) register file
356
//
357
or1200_rfram_generic rf_a(
358
        // Clock and reset
359
        .clk(clk),
360
        .rst(rst),
361
 
362
        // Port A
363
        .ce_a(rf_ena),
364
        .addr_a(rf_addra),
365
        .do_a(from_rfa),
366
 
367
        // Port B
368
        .ce_b(rf_enb),
369
        .addr_b(addrb),
370
        .do_b(from_rfb),
371
 
372
        // Port W
373
        .ce_w(rf_we),
374
        .we_w(rf_we),
375
        .addr_w(rf_addrw),
376
        .di_w(rf_dataw)
377
);
378
 
379
`else
380
 
381
//
382
// RFRAM type not specified
383
//
384
initial begin
385
        $display("Define RFRAM type.");
386
        $finish;
387
end
388
 
389
`endif
390
`endif
391
`endif
392
 
393
endmodule

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