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//////////////////////////////////////////////////////////////////////
////                                                              ////
////  OR1200's register file inside CPU                           ////
////                                                              ////
////  This file is part of the OpenRISC 1200 project              ////
////  http://www.opencores.org/project,or1k                       ////
////                                                              ////
////  Description                                                 ////
////  Instantiation of register file memories                     ////
////                                                              ////
////  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                     ////
////                                                              ////
//////////////////////////////////////////////////////////////////////
//
// $Log: or1200_rf.v,v $
// Revision 2.0  2010/06/30 11:00:00  ORSoC
// Minor update: 
// Bugs fixed, coding style changed. 
//
 
// synopsys translate_off
`include "timescale.v"
// synopsys translate_on
`include "or1200_defines.v"
 
module or1200_rf(
        // Clock and reset
        clk, rst,
 
        // Write i/f
        cy_we_i, cy_we_o, supv, wb_freeze, addrw, dataw, we, flushpipe,
 
        // Read i/f
        id_freeze, addra, addrb, dataa, datab, rda, rdb,
 
        // Debug
        spr_cs, spr_write, spr_addr, spr_dat_i, spr_dat_o, du_read
);
 
parameter dw = `OR1200_OPERAND_WIDTH;
parameter aw = `OR1200_REGFILE_ADDR_WIDTH;
 
//
// I/O
//
 
//
// Clock and reset
//
input                           clk;
input                           rst;
 
//
// Write i/f
//
input                           cy_we_i;
output                          cy_we_o;
input                           supv;
input                           wb_freeze;
input   [aw-1:0]         addrw;
input   [dw-1:0]         dataw;
input                           we;
input                           flushpipe;
 
//
// Read i/f
//
input                           id_freeze;
input   [aw-1:0]         addra;
input   [aw-1:0]         addrb;
output  [dw-1:0]         dataa;
output  [dw-1:0]         datab;
input                           rda;
input                           rdb;
 
//
// SPR access for debugging purposes
//
input                           spr_cs;
input                           spr_write;
input   [31:0]                   spr_addr;
input   [31:0]                   spr_dat_i;
output  [31:0]                   spr_dat_o;
input                           du_read;
 
//
// Internal wires and regs
//
wire    [dw-1:0]         from_rfa;
wire    [dw-1:0]         from_rfb;
wire    [aw-1:0]         rf_addra;
wire    [aw-1:0]         rf_addrw;
wire    [dw-1:0]         rf_dataw;
wire                            rf_we;
wire                            spr_valid;
wire                            rf_ena;
wire                            rf_enb;
reg                             rf_we_allow;
 
   // Logic to restore output on RFA after debug unit has read out via SPR if.
   // Problem was that the incorrect output would be on RFA after debug unit
   // had read out  - this is bad if that output is relied upon by execute
   // stage for next instruction. We simply save the last address for rf A and
   // and re-read it whenever the SPR select goes low, so we must remember
   // the last address and generate a signal for falling edge of SPR cs.
   // -- Julius
 
   // Detect falling edge of SPR select 
   reg                          spr_du_cs;
   wire                         spr_cs_fe;
   // Track RF A's address each time it's enabled
   reg  [aw-1:0]         addra_last;
 
 
   always @(posedge clk)
     if (rf_ena & !(spr_cs_fe | (du_read & spr_cs)))
       addra_last <= addra;
 
   always @(posedge clk)
     spr_du_cs <= spr_cs & du_read;
 
   assign spr_cs_fe = spr_du_cs & !(spr_cs & du_read);
 
 
//
// SPR access is valid when spr_cs is asserted and
// SPR address matches GPR addresses
//
assign spr_valid = spr_cs & (spr_addr[10:5] == `OR1200_SPR_RF);
 
//
// SPR data output is always from RF A
//
assign spr_dat_o = from_rfa;
 
//
// Operand A comes from RF or from saved A register
//
assign dataa = from_rfa;
 
//
// Operand B comes from RF or from saved B register
//
assign datab = from_rfb;
 
//
// RF A read address is either from SPRS or normal from CPU control
//
assign rf_addra = (spr_valid & !spr_write) ? spr_addr[4:0] :
                  spr_cs_fe ? addra_last : addra;
 
//
// RF write address is either from SPRS or normal from CPU control
//
assign rf_addrw = (spr_valid & spr_write) ? spr_addr[4:0] : addrw;
 
//
// RF write data is either from SPRS or normal from CPU datapath
//
assign rf_dataw = (spr_valid & spr_write) ? spr_dat_i : dataw;
 
//
// RF write enable is either from SPRS or normal from CPU control
//
always @(`OR1200_RST_EVENT rst or posedge clk)
        if (rst == `OR1200_RST_VALUE)
                rf_we_allow <=  1'b1;
        else if (~wb_freeze)
                rf_we_allow <=  ~flushpipe;
 
//assign rf_we = ((spr_valid & spr_write) | (we & ~wb_freeze)) & rf_we_allow & (supv | (|rf_addrw));
assign rf_we = ((spr_valid & spr_write) | (we & ~wb_freeze)) & rf_we_allow;
//assign cy_we_o = cy_we_i && rf_we;
assign cy_we_o = cy_we_i && ~wb_freeze && rf_we_allow;
 
 
//
// CS RF A asserted when instruction reads operand A and ID stage
// is not stalled
//
//assign rf_ena = rda & ~id_freeze | spr_valid; // probably works with fixed binutils
assign rf_ena = (rda & ~id_freeze) | (spr_valid & !spr_write) | spr_cs_fe;      // probably works with fixed binutils
// assign rf_ena = 1'b1;                        // does not work with single-stepping
//assign rf_ena = ~id_freeze | spr_valid;       // works with broken binutils 
 
//
// CS RF B asserted when instruction reads operand B and ID stage
// is not stalled
//
//assign rf_enb = rdb & ~id_freeze | spr_valid;
assign rf_enb = rdb & ~id_freeze;
// assign rf_enb = 1'b1;
//assign rf_enb = ~id_freeze | spr_valid;       // works with broken binutils 
 
`ifdef OR1200_RFRAM_TWOPORT
 
//
// Instantiation of register file two-port RAM A
//
or1200_tpram_32x32 rf_a(
        // Port A
        .clk_a(clk),
        .rst_a(rst),
        .ce_a(rf_ena),
        .we_a(1'b0),
        .oe_a(1'b1),
        .addr_a(rf_addra),
        .di_a(32'h0000_0000),
        .do_a(from_rfa),
 
        // Port B
        .clk_b(clk),
        .rst_b(rst),
        .ce_b(rf_we),
        .we_b(rf_we),
        .oe_b(1'b0),
        .addr_b(rf_addrw),
        .di_b(rf_dataw),
        .do_b()
);
 
//
// Instantiation of register file two-port RAM B
//
or1200_tpram_32x32 rf_b(
        // Port A
        .clk_a(clk),
        .rst_a(rst),
        .ce_a(rf_enb),
        .we_a(1'b0),
        .oe_a(1'b1),
        .addr_a(addrb),
        .di_a(32'h0000_0000),
        .do_a(from_rfb),
 
        // Port B
        .clk_b(clk),
        .rst_b(rst),
        .ce_b(rf_we),
        .we_b(rf_we),
        .oe_b(1'b0),
        .addr_b(rf_addrw),
        .di_b(rf_dataw),
        .do_b()
);
 
`else
 
`ifdef OR1200_RFRAM_DUALPORT
 
//
// Instantiation of register file two-port RAM A
//
   or1200_dpram #
     (
      .aw(5),
      .dw(32)
      )
   rf_a
     (
      // Port A
      .clk_a(clk),
      .ce_a(rf_ena),
      .addr_a(rf_addra),
      .do_a(from_rfa),
 
      // Port B
      .clk_b(clk),
      .ce_b(rf_we),
      .we_b(rf_we),
      .addr_b(rf_addrw),
      .di_b(rf_dataw)
      );
 
   //
   // Instantiation of register file two-port RAM B
   //
   or1200_dpram #
     (
      .aw(5),
      .dw(32)
      )
   rf_b
     (
      // Port A
      .clk_a(clk),
      .ce_a(rf_enb),
      .addr_a(addrb),
      .do_a(from_rfb),
 
      // Port B
      .clk_b(clk),
      .ce_b(rf_we),
      .we_b(rf_we),
      .addr_b(rf_addrw),
      .di_b(rf_dataw)
      );
 
`else
 
`ifdef OR1200_RFRAM_GENERIC
 
//
// Instantiation of generic (flip-flop based) register file
//
or1200_rfram_generic rf_a(
        // Clock and reset
        .clk(clk),
        .rst(rst),
 
        // Port A
        .ce_a(rf_ena),
        .addr_a(rf_addra),
        .do_a(from_rfa),
 
        // Port B
        .ce_b(rf_enb),
        .addr_b(addrb),
        .do_b(from_rfb),
 
        // Port W
        .ce_w(rf_we),
        .we_w(rf_we),
        .addr_w(rf_addrw),
        .di_w(rf_dataw)
);
 
`else
 
//
// RFRAM type not specified
//
initial begin
        $display("Define RFRAM type.");
        $finish;
end
 
`endif
`endif
`endif
 
endmodule

Line No.	Rev	Author	Line
1	10	unneback	`//////////////////////////////////////////////////////////////////////`
2			`//// ////`
3			`//// OR1200's register file inside CPU ////`
4			`//// ////`
5			`//// This file is part of the OpenRISC 1200 project ////`
6	186	julius	`//// http://www.opencores.org/project,or1k ////`
7	10	unneback	`//// ////`
8			`//// Description ////`
9			`//// Instantiation of register file memories ////`
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	141	marcus.erl	`// $Log: or1200_rf.v,v $`
45			`// Revision 2.0 2010/06/30 11:00:00 ORSoC`
46			`// Minor update:`
47			`// Bugs fixed, coding style changed.`
48			`//`
49	10	unneback
50			`// synopsys translate_off`
51			`include "timescale.v"
52			`// synopsys translate_on`
53			`include "or1200_defines.v"
54
55			`module or1200_rf(`
56			`// Clock and reset`
57			`clk, rst,`
58
59			`// Write i/f`
60	141	marcus.erl	`cy_we_i, cy_we_o, supv, wb_freeze, addrw, dataw, we, flushpipe,`
61	10	unneback
62			`// Read i/f`
63			`id_freeze, addra, addrb, dataa, datab, rda, rdb,`
64
65			`// Debug`
66	258	julius	`spr_cs, spr_write, spr_addr, spr_dat_i, spr_dat_o, du_read`
67	10	unneback	`);`
68
69			parameter dw = `OR1200_OPERAND_WIDTH;
70			parameter aw = `OR1200_REGFILE_ADDR_WIDTH;
71
72			`//`
73			`// I/O`
74			`//`
75
76			`//`
77			`// Clock and reset`
78			`//`
79			`input clk;`
80			`input rst;`
81
82			`//`
83			`// Write i/f`
84			`//`
85	141	marcus.erl	`input cy_we_i;`
86			`output cy_we_o;`
87	10	unneback	`input supv;`
88			`input wb_freeze;`
89			`input [aw-1:0] addrw;`
90			`input [dw-1:0] dataw;`
91			`input we;`
92			`input flushpipe;`
93
94			`//`
95			`// Read i/f`
96			`//`
97			`input id_freeze;`
98			`input [aw-1:0] addra;`
99			`input [aw-1:0] addrb;`
100			`output [dw-1:0] dataa;`
101			`output [dw-1:0] datab;`
102			`input rda;`
103			`input rdb;`
104
105			`//`
106			`// SPR access for debugging purposes`
107			`//`
108			`input spr_cs;`
109			`input spr_write;`
110			`input [31:0] spr_addr;`
111			`input [31:0] spr_dat_i;`
112			`output [31:0] spr_dat_o;`
113	258	julius	`input du_read;`
114
115	10	unneback	`//`
116			`// Internal wires and regs`
117			`//`
118			`wire [dw-1:0] from_rfa;`
119			`wire [dw-1:0] from_rfb;`
120			`wire [aw-1:0] rf_addra;`
121			`wire [aw-1:0] rf_addrw;`
122			`wire [dw-1:0] rf_dataw;`
123			`wire rf_we;`
124			`wire spr_valid;`
125			`wire rf_ena;`
126			`wire rf_enb;`
127			`reg rf_we_allow;`
128
129	258	julius	`// Logic to restore output on RFA after debug unit has read out via SPR if.`
130			`// Problem was that the incorrect output would be on RFA after debug unit`
131			`// had read out - this is bad if that output is relied upon by execute`
132			`// stage for next instruction. We simply save the last address for rf A and`
133			`// and re-read it whenever the SPR select goes low, so we must remember`
134			`// the last address and generate a signal for falling edge of SPR cs.`
135			`// -- Julius`
136
137			`// Detect falling edge of SPR select`
138			`reg spr_du_cs;`
139			`wire spr_cs_fe;`
140			`// Track RF A's address each time it's enabled`
141			`reg [aw-1:0] addra_last;`
142
143
144			`always @(posedge clk)`
145			`if (rf_ena & !(spr_cs_fe \| (du_read & spr_cs)))`
146			`addra_last <= addra;`
147
148			`always @(posedge clk)`
149			`spr_du_cs <= spr_cs & du_read;`
150
151			`assign spr_cs_fe = spr_du_cs & !(spr_cs & du_read);`
152
153
154	10	unneback	`//`
155			`// SPR access is valid when spr_cs is asserted and`
156			`// SPR address matches GPR addresses`
157			`//`
158			assign spr_valid = spr_cs & (spr_addr[10:5] == `OR1200_SPR_RF);
159
160			`//`
161			`// SPR data output is always from RF A`
162			`//`
163			`assign spr_dat_o = from_rfa;`
164
165			`//`
166			`// Operand A comes from RF or from saved A register`
167			`//`
168	141	marcus.erl	`assign dataa = from_rfa;`
169	10	unneback
170			`//`
171			`// Operand B comes from RF or from saved B register`
172			`//`
173	141	marcus.erl	`assign datab = from_rfb;`
174	10	unneback
175			`//`
176			`// RF A read address is either from SPRS or normal from CPU control`
177			`//`
178	258	julius	`assign rf_addra = (spr_valid & !spr_write) ? spr_addr[4:0] :`
179			`spr_cs_fe ? addra_last : addra;`
180	10	unneback
181			`//`
182			`// RF write address is either from SPRS or normal from CPU control`
183			`//`
184			`assign rf_addrw = (spr_valid & spr_write) ? spr_addr[4:0] : addrw;`
185
186			`//`
187			`// RF write data is either from SPRS or normal from CPU datapath`
188			`//`
189			`assign rf_dataw = (spr_valid & spr_write) ? spr_dat_i : dataw;`
190
191			`//`
192			`// RF write enable is either from SPRS or normal from CPU control`
193			`//`
194	358	julius	always @(`OR1200_RST_EVENT rst or posedge clk)
195			if (rst == `OR1200_RST_VALUE)
196	258	julius	`rf_we_allow <= 1'b1;`
197	10	unneback	`else if (~wb_freeze)`
198	258	julius	`rf_we_allow <= ~flushpipe;`
199	10	unneback
200	141	marcus.erl	`//assign rf_we = ((spr_valid & spr_write) \| (we & ~wb_freeze)) & rf_we_allow & (supv \| (\|rf_addrw));`
201			`assign rf_we = ((spr_valid & spr_write) \| (we & ~wb_freeze)) & rf_we_allow;`
202			`//assign cy_we_o = cy_we_i && rf_we;`
203			`assign cy_we_o = cy_we_i && ~wb_freeze && rf_we_allow;`
204	258	julius
205
206	10	unneback	`//`
207			`// CS RF A asserted when instruction reads operand A and ID stage`
208			`// is not stalled`
209			`//`
210	141	marcus.erl	`//assign rf_ena = rda & ~id_freeze \| spr_valid; // probably works with fixed binutils`
211	258	julius	`assign rf_ena = (rda & ~id_freeze) \| (spr_valid & !spr_write) \| spr_cs_fe; // probably works with fixed binutils`
212	10	unneback	`// assign rf_ena = 1'b1; // does not work with single-stepping`
213			`//assign rf_ena = ~id_freeze \| spr_valid; // works with broken binutils`
214
215			`//`
216			`// CS RF B asserted when instruction reads operand B and ID stage`
217			`// is not stalled`
218			`//`
219	141	marcus.erl	`//assign rf_enb = rdb & ~id_freeze \| spr_valid;`
220			`assign rf_enb = rdb & ~id_freeze;`
221	10	unneback	`// assign rf_enb = 1'b1;`
222			`//assign rf_enb = ~id_freeze \| spr_valid; // works with broken binutils`
223
224			`ifdef OR1200_RFRAM_TWOPORT
225
226			`//`
227			`// Instantiation of register file two-port RAM A`
228			`//`
229			`or1200_tpram_32x32 rf_a(`
230			`// Port A`
231			`.clk_a(clk),`
232			`.rst_a(rst),`
233			`.ce_a(rf_ena),`
234			`.we_a(1'b0),`
235			`.oe_a(1'b1),`
236			`.addr_a(rf_addra),`
237			`.di_a(32'h0000_0000),`
238			`.do_a(from_rfa),`
239
240			`// Port B`
241			`.clk_b(clk),`
242			`.rst_b(rst),`
243			`.ce_b(rf_we),`
244			`.we_b(rf_we),`
245			`.oe_b(1'b0),`
246			`.addr_b(rf_addrw),`
247			`.di_b(rf_dataw),`
248			`.do_b()`
249			`);`
250
251			`//`
252			`// Instantiation of register file two-port RAM B`
253			`//`
254			`or1200_tpram_32x32 rf_b(`
255			`// Port A`
256			`.clk_a(clk),`
257			`.rst_a(rst),`
258			`.ce_a(rf_enb),`
259			`.we_a(1'b0),`
260			`.oe_a(1'b1),`
261			`.addr_a(addrb),`
262			`.di_a(32'h0000_0000),`
263			`.do_a(from_rfb),`
264
265			`// Port B`
266			`.clk_b(clk),`
267			`.rst_b(rst),`
268			`.ce_b(rf_we),`
269			`.we_b(rf_we),`
270			`.oe_b(1'b0),`
271			`.addr_b(rf_addrw),`
272			`.di_b(rf_dataw),`
273			`.do_b()`
274			`);`
275
276			`else
277
278			`ifdef OR1200_RFRAM_DUALPORT
279
280			`//`
281			`// Instantiation of register file two-port RAM A`
282			`//`
283	141	marcus.erl	`or1200_dpram #`
284			`(`
285			`.aw(5),`
286			`.dw(32)`
287			`)`
288			`rf_a`
289			`(`
290			`// Port A`
291			`.clk_a(clk),`
292			`.ce_a(rf_ena),`
293			`.addr_a(rf_addra),`
294			`.do_a(from_rfa),`
295
296			`// Port B`
297			`.clk_b(clk),`
298			`.ce_b(rf_we),`
299			`.we_b(rf_we),`
300			`.addr_b(rf_addrw),`
301			`.di_b(rf_dataw)`
302			`);`
303	10	unneback
304	141	marcus.erl	`//`
305			`// Instantiation of register file two-port RAM B`
306			`//`
307			`or1200_dpram #`
308			`(`
309			`.aw(5),`
310			`.dw(32)`
311			`)`
312			`rf_b`
313			`(`
314			`// Port A`
315			`.clk_a(clk),`
316			`.ce_a(rf_enb),`
317			`.addr_a(addrb),`
318			`.do_a(from_rfb),`
319
320			`// Port B`
321			`.clk_b(clk),`
322			`.ce_b(rf_we),`
323			`.we_b(rf_we),`
324			`.addr_b(rf_addrw),`
325			`.di_b(rf_dataw)`
326			`);`
327
328	10	unneback	`else
329
330			`ifdef OR1200_RFRAM_GENERIC
331
332			`//`
333			`// Instantiation of generic (flip-flop based) register file`
334			`//`
335			`or1200_rfram_generic rf_a(`
336			`// Clock and reset`
337			`.clk(clk),`
338			`.rst(rst),`
339
340			`// Port A`
341			`.ce_a(rf_ena),`
342			`.addr_a(rf_addra),`
343			`.do_a(from_rfa),`
344
345			`// Port B`
346			`.ce_b(rf_enb),`
347			`.addr_b(addrb),`
348			`.do_b(from_rfb),`
349
350			`// Port W`
351			`.ce_w(rf_we),`
352			`.we_w(rf_we),`
353			`.addr_w(rf_addrw),`
354			`.di_w(rf_dataw)`
355			`);`
356
357			`else
358
359			`//`
360			`// RFRAM type not specified`
361			`//`
362			`initial begin`
363			`$display("Define RFRAM type.");`
364			`$finish;`
365			`end`
366
367			`endif
368			`endif
369			`endif
370
371			`endmodule`

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