1 //----------------------------------------------------------------------------
2 // Copyright (C) 2001 Authors
4 // This source file may be used and distributed without restriction provided
5 // that this copyright statement is not removed from the file and that any
6 // derivative work contains the original copyright notice and the associated
9 // This source file is free software; you can redistribute it and/or modify
10 // it under the terms of the GNU Lesser General Public License as published
11 // by the Free Software Foundation; either version 2.1 of the License, or
12 // (at your option) any later version.
14 // This source is distributed in the hope that it will be useful, but WITHOUT
15 // ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
16 // FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
17 // License for more details.
19 // You should have received a copy of the GNU Lesser General Public License
20 // along with this source; if not, write to the Free Software Foundation,
21 // Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
23 //----------------------------------------------------------------------------
25 // *File Name: omsp_register_file.v
27 // *Module Description:
28 // openMSP430 Register files
31 // - Olivier Girard, olgirard@gmail.com
33 //----------------------------------------------------------------------------
35 // $LastChangedBy: olivier.girard $
36 // $LastChangedDate: 2009-12-29 20:10:34 +0100 (Tue, 29 Dec 2009) $
37 //----------------------------------------------------------------------------
38 `include "timescale.v"
39 `include "openMSP430_defines.v"
41 module omsp_register_file (
44 cpuoff, // Turns off the CPU
45 gie, // General interrupt enable
46 oscoff, // Turns off LFXT1 clock input
47 pc_sw, // Program counter software value
48 pc_sw_wr, // Program counter software write
49 reg_dest, // Selected register destination content
50 reg_src, // Selected register source content
51 scg1, // System clock generator 1. Turns off the SMCLK
52 status, // R2 Status {V,N,Z,C}
55 alu_stat, // ALU Status {V,N,Z,C}
56 alu_stat_wr, // ALU Status write {V,N,Z,C}
57 inst_bw, // Decoded Inst: byte width
58 inst_dest, // Register destination selection
59 inst_src, // Register source selection
60 mclk, // Main system clock
61 pc, // Program counter
62 puc, // Main system reset
63 reg_dest_val, // Selected register destination value
64 reg_dest_wr, // Write selected register destination
65 reg_pc_call, // Trigger PC update for a CALL instruction
66 reg_sp_val, // Stack Pointer next value
67 reg_sp_wr, // Stack Pointer write
68 reg_sr_wr, // Status register update for RETI instruction
69 reg_sr_clr, // Status register clear for interrupts
70 reg_incr // Increment source register
75 output cpuoff; // Turns off the CPU
76 output gie; // General interrupt enable
77 output oscoff; // Turns off LFXT1 clock input
78 output [15:0] pc_sw; // Program counter software value
79 output pc_sw_wr; // Program counter software write
80 output [15:0] reg_dest; // Selected register destination content
81 output [15:0] reg_src; // Selected register source content
82 output scg1; // System clock generator 1. Turns off the SMCLK
83 output [3:0] status; // R2 Status {V,N,Z,C}
87 input [3:0] alu_stat; // ALU Status {V,N,Z,C}
88 input [3:0] alu_stat_wr; // ALU Status write {V,N,Z,C}
89 input inst_bw; // Decoded Inst: byte width
90 input [15:0] inst_dest; // Register destination selection
91 input [15:0] inst_src; // Register source selection
92 input mclk; // Main system clock
93 input [15:0] pc; // Program counter
94 input puc; // Main system reset
95 input [15:0] reg_dest_val; // Selected register destination value
96 input reg_dest_wr; // Write selected register destination
97 input reg_pc_call; // Trigger PC update for a CALL instruction
98 input [15:0] reg_sp_val; // Stack Pointer next value
99 input reg_sp_wr; // Stack Pointer write
100 input reg_sr_wr; // Status register update for RETI instruction
101 input reg_sr_clr; // Status register clear for interrupts
102 input reg_incr; // Increment source register
105 //=============================================================================
106 // 1) AUTOINCREMENT UNIT
107 //=============================================================================
109 wire [15:0] incr_op = inst_bw ? 16'h0001 : 16'h0002;
110 wire [15:0] reg_incr_val = reg_src+incr_op;
112 wire [15:0] reg_dest_val_in = inst_bw ? {8'h00,reg_dest_val[7:0]} : reg_dest_val;
115 //=============================================================================
116 // 2) SPECIAL REGISTERS (R1/R2/R3)
117 //=============================================================================
119 // Source input selection mask (for interrupt support)
120 //-----------------------------------------------------
122 wire [15:0] inst_src_in = reg_sr_clr ? 16'h0004 : inst_src;
125 // R0: Program counter
126 //---------------------
130 wire [15:0] pc_sw = reg_dest_val_in;
131 wire pc_sw_wr = (inst_dest[0] & reg_dest_wr) | reg_pc_call;
135 //-------------------
137 wire r1_wr = inst_dest[1] & reg_dest_wr;
138 wire r1_inc = inst_src_in[1] & reg_incr;
140 always @(posedge mclk or posedge puc)
141 if (puc) r1 <= 16'h0000;
142 else if (r1_wr) r1 <= reg_dest_val_in & 16'hfffe;
143 else if (reg_sp_wr) r1 <= reg_sp_val & 16'hfffe;
144 else if (r1_inc) r1 <= reg_incr_val & 16'hfffe;
147 // R2: Status register
148 //---------------------
150 wire r2_wr = (inst_dest[2] & reg_dest_wr) | reg_sr_wr;
152 wire r2_c = alu_stat_wr[0] ? alu_stat[0] :
153 r2_wr ? reg_dest_val_in[0] : r2[0]; // C
155 wire r2_z = alu_stat_wr[1] ? alu_stat[1] :
156 r2_wr ? reg_dest_val_in[1] : r2[1]; // Z
158 wire r2_n = alu_stat_wr[2] ? alu_stat[2] :
159 r2_wr ? reg_dest_val_in[2] : r2[2]; // N
161 wire [7:3] r2_nxt = r2_wr ? reg_dest_val_in[7:3] : r2[7:3];
163 wire r2_v = alu_stat_wr[3] ? alu_stat[3] :
164 r2_wr ? reg_dest_val_in[8] : r2[8]; // V
167 always @(posedge mclk or posedge puc)
168 if (puc) r2 <= 16'h0000;
169 else if (reg_sr_clr) r2 <= 16'h0000;
170 else r2 <= {7'h00, r2_v, r2_nxt, r2_n, r2_z, r2_c};
172 assign status = {r2[8], r2[2:0]};
174 assign cpuoff = r2[4] | (r2_nxt[4] & r2_wr);
175 assign oscoff = r2[5];
179 // R3: Constant generator
180 //------------------------
182 wire r3_wr = inst_dest[3] & reg_dest_wr;
183 wire r3_inc = inst_src_in[3] & reg_incr;
185 always @(posedge mclk or posedge puc)
186 if (puc) r3 <= 16'h0000;
187 else if (r3_wr) r3 <= reg_dest_val_in;
188 else if (r3_inc) r3 <= reg_incr_val;
191 //=============================================================================
192 // 4) GENERAL PURPOSE REGISTERS (R4...R15)
193 //=============================================================================
197 wire r4_wr = inst_dest[4] & reg_dest_wr;
198 wire r4_inc = inst_src_in[4] & reg_incr;
199 always @(posedge mclk or posedge puc)
200 if (puc) r4 <= 16'h0000;
201 else if (r4_wr) r4 <= reg_dest_val_in;
202 else if (r4_inc) r4 <= reg_incr_val;
206 wire r5_wr = inst_dest[5] & reg_dest_wr;
207 wire r5_inc = inst_src_in[5] & reg_incr;
208 always @(posedge mclk or posedge puc)
209 if (puc) r5 <= 16'h0000;
210 else if (r5_wr) r5 <= reg_dest_val_in;
211 else if (r5_inc) r5 <= reg_incr_val;
215 wire r6_wr = inst_dest[6] & reg_dest_wr;
216 wire r6_inc = inst_src_in[6] & reg_incr;
217 always @(posedge mclk or posedge puc)
218 if (puc) r6 <= 16'h0000;
219 else if (r6_wr) r6 <= reg_dest_val_in;
220 else if (r6_inc) r6 <= reg_incr_val;
224 wire r7_wr = inst_dest[7] & reg_dest_wr;
225 wire r7_inc = inst_src_in[7] & reg_incr;
226 always @(posedge mclk or posedge puc)
227 if (puc) r7 <= 16'h0000;
228 else if (r7_wr) r7 <= reg_dest_val_in;
229 else if (r7_inc) r7 <= reg_incr_val;
233 wire r8_wr = inst_dest[8] & reg_dest_wr;
234 wire r8_inc = inst_src_in[8] & reg_incr;
235 always @(posedge mclk or posedge puc)
236 if (puc) r8 <= 16'h0000;
237 else if (r8_wr) r8 <= reg_dest_val_in;
238 else if (r8_inc) r8 <= reg_incr_val;
242 wire r9_wr = inst_dest[9] & reg_dest_wr;
243 wire r9_inc = inst_src_in[9] & reg_incr;
244 always @(posedge mclk or posedge puc)
245 if (puc) r9 <= 16'h0000;
246 else if (r9_wr) r9 <= reg_dest_val_in;
247 else if (r9_inc) r9 <= reg_incr_val;
251 wire r10_wr = inst_dest[10] & reg_dest_wr;
252 wire r10_inc = inst_src_in[10] & reg_incr;
253 always @(posedge mclk or posedge puc)
254 if (puc) r10 <= 16'h0000;
255 else if (r10_wr) r10 <= reg_dest_val_in;
256 else if (r10_inc) r10 <= reg_incr_val;
260 wire r11_wr = inst_dest[11] & reg_dest_wr;
261 wire r11_inc = inst_src_in[11] & reg_incr;
262 always @(posedge mclk or posedge puc)
263 if (puc) r11 <= 16'h0000;
264 else if (r11_wr) r11 <= reg_dest_val_in;
265 else if (r11_inc) r11 <= reg_incr_val;
269 wire r12_wr = inst_dest[12] & reg_dest_wr;
270 wire r12_inc = inst_src_in[12] & reg_incr;
271 always @(posedge mclk or posedge puc)
272 if (puc) r12 <= 16'h0000;
273 else if (r12_wr) r12 <= reg_dest_val_in;
274 else if (r12_inc) r12 <= reg_incr_val;
278 wire r13_wr = inst_dest[13] & reg_dest_wr;
279 wire r13_inc = inst_src_in[13] & reg_incr;
280 always @(posedge mclk or posedge puc)
281 if (puc) r13 <= 16'h0000;
282 else if (r13_wr) r13 <= reg_dest_val_in;
283 else if (r13_inc) r13 <= reg_incr_val;
287 wire r14_wr = inst_dest[14] & reg_dest_wr;
288 wire r14_inc = inst_src_in[14] & reg_incr;
289 always @(posedge mclk or posedge puc)
290 if (puc) r14 <= 16'h0000;
291 else if (r14_wr) r14 <= reg_dest_val_in;
292 else if (r14_inc) r14 <= reg_incr_val;
296 wire r15_wr = inst_dest[15] & reg_dest_wr;
297 wire r15_inc = inst_src_in[15] & reg_incr;
298 always @(posedge mclk or posedge puc)
299 if (puc) r15 <= 16'h0000;
300 else if (r15_wr) r15 <= reg_dest_val_in;
301 else if (r15_inc) r15 <= reg_incr_val;
304 //=============================================================================
306 //=============================================================================
308 assign reg_src = (r0 & {16{inst_src_in[0]}}) |
309 (r1 & {16{inst_src_in[1]}}) |
310 (r2 & {16{inst_src_in[2]}}) |
311 (r3 & {16{inst_src_in[3]}}) |
312 (r4 & {16{inst_src_in[4]}}) |
313 (r5 & {16{inst_src_in[5]}}) |
314 (r6 & {16{inst_src_in[6]}}) |
315 (r7 & {16{inst_src_in[7]}}) |
316 (r8 & {16{inst_src_in[8]}}) |
317 (r9 & {16{inst_src_in[9]}}) |
318 (r10 & {16{inst_src_in[10]}}) |
319 (r11 & {16{inst_src_in[11]}}) |
320 (r12 & {16{inst_src_in[12]}}) |
321 (r13 & {16{inst_src_in[13]}}) |
322 (r14 & {16{inst_src_in[14]}}) |
323 (r15 & {16{inst_src_in[15]}});
325 assign reg_dest = (r0 & {16{inst_dest[0]}}) |
326 (r1 & {16{inst_dest[1]}}) |
327 (r2 & {16{inst_dest[2]}}) |
328 (r3 & {16{inst_dest[3]}}) |
329 (r4 & {16{inst_dest[4]}}) |
330 (r5 & {16{inst_dest[5]}}) |
331 (r6 & {16{inst_dest[6]}}) |
332 (r7 & {16{inst_dest[7]}}) |
333 (r8 & {16{inst_dest[8]}}) |
334 (r9 & {16{inst_dest[9]}}) |
335 (r10 & {16{inst_dest[10]}}) |
336 (r11 & {16{inst_dest[11]}}) |
337 (r12 & {16{inst_dest[12]}}) |
338 (r13 & {16{inst_dest[13]}}) |
339 (r14 & {16{inst_dest[14]}}) |
340 (r15 & {16{inst_dest[15]}});
343 endmodule // omsp_register_file
345 `include "openMSP430_undefines.v"