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Commit | Line | Data |
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1 | `include "ARM_Constants.v" | |
2 | ||
3 | module Memory( | |
4 | input clk, | |
5 | input Nrst, | |
6 | ||
7 | input flush, | |
8 | ||
9 | /* bus interface */ | |
10 | output reg [31:0] busaddr, | |
11 | output reg rd_req, | |
12 | output reg wr_req, | |
13 | input rw_wait, | |
14 | output reg [31:0] wr_data, | |
15 | input [31:0] rd_data, | |
16 | output reg [2:0] data_size, | |
17 | ||
18 | /* regfile interface */ | |
19 | output reg [3:0] st_read, | |
20 | input [31:0] st_data, | |
21 | ||
22 | /* Coprocessor interface */ | |
23 | output reg cp_req, | |
24 | input cp_ack, | |
25 | input cp_busy, | |
26 | output reg cp_rnw, /* 1 = read from CP, 0 = write to CP */ | |
27 | input [31:0] cp_read, | |
28 | output reg [31:0] cp_write, | |
29 | ||
30 | /* stage inputs */ | |
31 | input inbubble, | |
32 | input [31:0] pc, | |
33 | input [31:0] insn, | |
34 | input [31:0] op0, | |
35 | input [31:0] op1, | |
36 | input [31:0] op2, | |
37 | input [31:0] spsr, | |
38 | input [31:0] cpsr, | |
39 | input write_reg, | |
40 | input [3:0] write_num, | |
41 | input [31:0] write_data, | |
42 | ||
43 | /* outputs */ | |
44 | output reg outstall, | |
45 | output reg outbubble, | |
46 | output reg [31:0] outpc, | |
47 | output reg [31:0] outinsn, | |
48 | output reg out_write_reg = 1'b0, | |
49 | output reg [3:0] out_write_num = 4'bxxxx, | |
50 | output reg [31:0] out_write_data = 32'hxxxxxxxx, | |
51 | output reg [31:0] outspsr = 32'hxxxxxxxx, | |
52 | output reg [31:0] outcpsr = 32'hxxxxxxxx | |
53 | ); | |
54 | ||
55 | reg [31:0] addr, raddr, prev_raddr, next_regdata, next_outcpsr; | |
56 | reg [31:0] prevaddr; | |
57 | reg [3:0] next_regsel, cur_reg, prev_reg; | |
58 | reg next_writeback; | |
59 | ||
60 | reg next_outbubble; | |
61 | reg next_write_reg; | |
62 | reg [3:0] next_write_num; | |
63 | reg [31:0] next_write_data; | |
64 | ||
65 | reg [1:0] lsr_state = 2'b01, next_lsr_state; | |
66 | reg [31:0] align_s1, align_s2, align_rddata; | |
67 | ||
68 | reg [1:0] lsrh_state = 2'b01, next_lsrh_state; | |
69 | reg [31:0] lsrh_rddata; | |
70 | reg [15:0] lsrh_rddata_s1; | |
71 | reg [7:0] lsrh_rddata_s2; | |
72 | ||
73 | reg [15:0] regs, next_regs; | |
74 | reg [2:0] lsm_state = 3'b001, next_lsm_state; | |
75 | reg [5:0] offset, prev_offset, offset_sel; | |
76 | ||
77 | reg [31:0] swp_oldval, next_swp_oldval; | |
78 | reg [1:0] swp_state = 2'b01, next_swp_state; | |
79 | ||
80 | always @(posedge clk) | |
81 | begin | |
82 | outpc <= pc; | |
83 | outinsn <= insn; | |
84 | outbubble <= next_outbubble; | |
85 | out_write_reg <= next_write_reg; | |
86 | out_write_num <= next_write_num; | |
87 | out_write_data <= next_write_data; | |
88 | regs <= next_regs; | |
89 | prev_reg <= cur_reg; | |
90 | if (!rw_wait) | |
91 | prev_offset <= offset; | |
92 | prev_raddr <= raddr; | |
93 | outcpsr <= next_outcpsr; | |
94 | outspsr <= spsr; | |
95 | swp_state <= next_swp_state; | |
96 | lsm_state <= next_lsm_state; | |
97 | lsr_state <= next_lsr_state; | |
98 | lsrh_state <= next_lsrh_state; | |
99 | prevaddr <= addr; | |
100 | end | |
101 | ||
102 | reg delayedflush = 0; | |
103 | always @(posedge clk) | |
104 | if (flush && outstall /* halp! I can't do it now, maybe later? */) | |
105 | delayedflush <= 1; | |
106 | else if (!outstall /* anything has been handled this time around */) | |
107 | delayedflush <= 0; | |
108 | ||
109 | always @(*) | |
110 | begin | |
111 | addr = prevaddr; | |
112 | raddr = 32'hxxxxxxxx; | |
113 | rd_req = 1'b0; | |
114 | wr_req = 1'b0; | |
115 | wr_data = 32'hxxxxxxxx; | |
116 | busaddr = 32'hxxxxxxxx; | |
117 | data_size = 3'bxxx; | |
118 | outstall = 1'b0; | |
119 | next_write_reg = write_reg; | |
120 | next_write_num = write_num; | |
121 | next_write_data = write_data; | |
122 | next_outbubble = inbubble; | |
123 | next_regs = regs; | |
124 | cp_req = 1'b0; | |
125 | cp_rnw = 1'bx; | |
126 | cp_write = 32'hxxxxxxxx; | |
127 | offset = prev_offset; | |
128 | next_outcpsr = lsm_state == 3'b010 ? outcpsr : cpsr; | |
129 | lsrh_rddata = 32'hxxxxxxxx; | |
130 | lsrh_rddata_s1 = 16'hxxxx; | |
131 | lsrh_rddata_s2 = 8'hxx; | |
132 | next_lsm_state = lsm_state; | |
133 | next_lsr_state = lsr_state; | |
134 | next_lsrh_state = lsrh_state; | |
135 | next_swp_oldval = swp_oldval; | |
136 | next_swp_state = swp_state; | |
137 | cur_reg = prev_reg; | |
138 | ||
139 | /* XXX shit not given about endianness */ | |
140 | casez(insn) | |
141 | `DECODE_ALU_SWP: if(!inbubble) begin | |
142 | outstall = rw_wait; | |
143 | next_outbubble = rw_wait; | |
144 | busaddr = {op0[31:2], 2'b0}; | |
145 | data_size = insn[22] ? 3'b001 : 3'b100; | |
146 | case(swp_state) | |
147 | 2'b01: begin | |
148 | rd_req = 1'b1; | |
149 | outstall = 1'b1; | |
150 | if(!rw_wait) begin | |
151 | next_swp_state = 2'b10; | |
152 | next_swp_oldval = rd_data; | |
153 | end | |
154 | end | |
155 | 2'b10: begin | |
156 | wr_req = 1'b1; | |
157 | wr_data = insn[22] ? {4{op1[7:0]}} : op1; | |
158 | next_write_reg = 1'b1; | |
159 | next_write_num = insn[15:12]; | |
160 | next_write_data = insn[22] ? {24'b0, swp_oldval[7:0]} : swp_oldval; | |
161 | if(!rw_wait) | |
162 | next_swp_state = 2'b01; | |
163 | end | |
164 | default: begin end | |
165 | endcase | |
166 | end | |
167 | `DECODE_ALU_HDATA_REG, | |
168 | `DECODE_ALU_HDATA_IMM: if(!inbubble) begin | |
169 | next_outbubble = rw_wait; | |
170 | outstall = rw_wait; | |
171 | addr = insn[23] ? op0 + op1 : op0 - op1; /* up/down select */ | |
172 | raddr = insn[24] ? op0 : addr; /* pre/post increment */ | |
173 | busaddr = raddr; | |
174 | /* rotate to correct position */ | |
175 | case(insn[6:5]) | |
176 | 2'b00: begin end /* swp */ | |
177 | 2'b01: begin /* unsigned half */ | |
178 | wr_data = {2{op2[15:0]}}; /* XXX need to store halfword */ | |
179 | data_size = 3'b010; | |
180 | lsrh_rddata = {16'b0, raddr[1] ? rd_data[31:16] : rd_data[15:0]}; | |
181 | end | |
182 | 2'b10: begin /* signed byte */ | |
183 | wr_data = {4{op2[7:0]}}; | |
184 | data_size = 3'b001; | |
185 | lsrh_rddata_s1 = raddr[1] ? rd_data[31:16] : rd_data[15:0]; | |
186 | lsrh_rddata_s2 = raddr[0] ? lsrh_rddata_s1[15:8] : lsrh_rddata_s1[7:0]; | |
187 | lsrh_rddata = {{24{lsrh_rddata_s2[7]}}, lsrh_rddata_s2}; | |
188 | end | |
189 | 2'b11: begin /* signed half */ | |
190 | wr_data = {2{op2[15:0]}}; | |
191 | data_size = 3'b010; | |
192 | lsrh_rddata = raddr[1] ? {{16{rd_data[31]}}, rd_data[31:16]} : {{16{rd_data[15]}}, rd_data[15:0]}; | |
193 | end | |
194 | endcase | |
195 | ||
196 | case(lsrh_state) | |
197 | 2'b01: begin | |
198 | rd_req = insn[20]; | |
199 | wr_req = ~insn[20]; | |
200 | next_write_num = insn[15:12]; | |
201 | next_write_data = lsrh_rddata; | |
202 | if(insn[20]) begin | |
203 | next_write_reg = 1'b1; | |
204 | end | |
205 | if(insn[21] | !insn[24]) begin | |
206 | outstall = 1'b1; | |
207 | if(!rw_wait) | |
208 | next_lsrh_state = 2'b10; | |
209 | end | |
210 | end | |
211 | 2'b10: begin | |
212 | next_write_reg = 1'b1; | |
213 | next_write_num = insn[19:16]; | |
214 | next_write_data = addr; | |
215 | next_lsrh_state = 2'b10; | |
216 | end | |
217 | default: begin end | |
218 | endcase | |
219 | end | |
220 | `DECODE_LDRSTR_UNDEFINED: begin end | |
221 | `DECODE_LDRSTR: if(!inbubble) begin | |
222 | next_outbubble = rw_wait; | |
223 | outstall = rw_wait; | |
224 | addr = insn[23] ? op0 + op1 : op0 - op1; /* up/down select */ | |
225 | raddr = insn[24] ? addr : op0; /* pre/post increment */ | |
226 | busaddr = raddr; | |
227 | /* rotate to correct position */ | |
228 | align_s1 = raddr[1] ? {rd_data[15:0], rd_data[31:16]} : rd_data; | |
229 | align_s2 = raddr[0] ? {align_s1[7:0], align_s1[31:8]} : align_s1; | |
230 | /* select byte or word */ | |
231 | align_rddata = insn[22] ? {24'b0, align_s2[7:0]} : align_s2; | |
232 | wr_data = insn[22] ? {4{op2[7:0]}} : op2; /* XXX need to actually store just a byte */ | |
233 | data_size = insn[22] ? 3'b001 : 3'b100; | |
234 | case(lsr_state) | |
235 | 2'b01: begin | |
236 | rd_req = insn[20]; | |
237 | wr_req = ~insn[20]; | |
238 | next_write_reg = 1'b1; | |
239 | next_write_num = insn[15:12]; | |
240 | if(insn[20]) begin | |
241 | next_write_data = align_rddata; | |
242 | end | |
243 | if(insn[21] | !insn[24]) begin | |
244 | outstall = 1'b1; | |
245 | if(!rw_wait) | |
246 | next_lsr_state = 2'b10; | |
247 | end | |
248 | $display("LDRSTR: rd_req %d, wr_req %d, raddr %08x, wait %d", rd_req, wr_req, raddr, rw_wait); | |
249 | end | |
250 | 2'b10: begin | |
251 | next_write_reg = 1'b1; | |
252 | next_write_num = insn[19:16]; | |
253 | next_write_data = addr; | |
254 | next_lsr_state = 2'b01; | |
255 | end | |
256 | default: begin end | |
257 | endcase | |
258 | end | |
259 | /* XXX ldm/stm incorrect in that stupid case where one of the listed regs is the base reg */ | |
260 | `DECODE_LDMSTM: if(!inbubble) begin | |
261 | outstall = rw_wait; | |
262 | next_outbubble = rw_wait; | |
263 | data_size = 3'b100; | |
264 | case(lsm_state) | |
265 | 3'b001: begin | |
266 | // next_regs = insn[23] ? op1[15:0] : op1[0:15]; | |
267 | /** verilator can suck my dick */ | |
268 | $display("LDMSTM: Round 1: base register: %08x, reg list %b", op0, op1[15:0]); | |
269 | next_regs = insn[23] /* U */ ? op1[15:0] : {op1[0], op1[1], op1[2], op1[3], op1[4], op1[5], op1[6], op1[7], | |
270 | op1[8], op1[9], op1[10], op1[11], op1[12], op1[13], op1[14], op1[15]}; | |
271 | offset = 6'b0; | |
272 | outstall = 1'b1; | |
273 | next_lsm_state = 3'b010; | |
274 | end | |
275 | 3'b010: begin | |
276 | rd_req = insn[20]; | |
277 | wr_req = ~insn[20]; | |
278 | casez(regs) | |
279 | 16'b???????????????1: begin | |
280 | cur_reg = 4'h0; | |
281 | next_regs = {regs[15:1], 1'b0}; | |
282 | end | |
283 | 16'b??????????????10: begin | |
284 | cur_reg = 4'h1; | |
285 | next_regs = {regs[15:2], 2'b0}; | |
286 | end | |
287 | 16'b?????????????100: begin | |
288 | cur_reg = 4'h2; | |
289 | next_regs = {regs[15:3], 3'b0}; | |
290 | end | |
291 | 16'b????????????1000: begin | |
292 | cur_reg = 4'h3; | |
293 | next_regs = {regs[15:4], 4'b0}; | |
294 | end | |
295 | 16'b???????????10000: begin | |
296 | cur_reg = 4'h4; | |
297 | next_regs = {regs[15:5], 5'b0}; | |
298 | end | |
299 | 16'b??????????100000: begin | |
300 | cur_reg = 4'h5; | |
301 | next_regs = {regs[15:6], 6'b0}; | |
302 | end | |
303 | 16'b?????????1000000: begin | |
304 | cur_reg = 4'h6; | |
305 | next_regs = {regs[15:7], 7'b0}; | |
306 | end | |
307 | 16'b????????10000000: begin | |
308 | cur_reg = 4'h7; | |
309 | next_regs = {regs[15:8], 8'b0}; | |
310 | end | |
311 | 16'b???????100000000: begin | |
312 | cur_reg = 4'h8; | |
313 | next_regs = {regs[15:9], 9'b0}; | |
314 | end | |
315 | 16'b??????1000000000: begin | |
316 | cur_reg = 4'h9; | |
317 | next_regs = {regs[15:10], 10'b0}; | |
318 | end | |
319 | 16'b?????10000000000: begin | |
320 | cur_reg = 4'hA; | |
321 | next_regs = {regs[15:11], 11'b0}; | |
322 | end | |
323 | 16'b????100000000000: begin | |
324 | cur_reg = 4'hB; | |
325 | next_regs = {regs[15:12], 12'b0}; | |
326 | end | |
327 | 16'b???1000000000000: begin | |
328 | cur_reg = 4'hC; | |
329 | next_regs = {regs[15:13], 13'b0}; | |
330 | end | |
331 | 16'b??10000000000000: begin | |
332 | cur_reg = 4'hD; | |
333 | next_regs = {regs[15:14], 14'b0}; | |
334 | end | |
335 | 16'b?100000000000000: begin | |
336 | cur_reg = 4'hE; | |
337 | next_regs = {regs[15], 15'b0}; | |
338 | end | |
339 | 16'b1000000000000000: begin | |
340 | cur_reg = 4'hF; | |
341 | next_regs = 16'b0; | |
342 | end | |
343 | default: begin | |
344 | cur_reg = 4'hx; | |
345 | next_regs = 16'b0; | |
346 | end | |
347 | endcase | |
348 | cur_reg = insn[23] ? cur_reg : 4'hF - cur_reg; | |
349 | if(cur_reg == 4'hF && insn[22]) begin | |
350 | next_outcpsr = spsr; | |
351 | end | |
352 | ||
353 | offset = prev_offset + 6'h4; | |
354 | offset_sel = insn[24] ? offset : prev_offset; | |
355 | raddr = insn[23] ? op0 + {26'b0, offset_sel} : op0 - {26'b0, offset_sel}; | |
356 | if(insn[20]) begin | |
357 | next_write_reg = !rw_wait; | |
358 | next_write_num = cur_reg; | |
359 | next_write_data = rd_data; | |
360 | end | |
361 | if (rw_wait) begin | |
362 | next_regs = regs; | |
363 | cur_reg = prev_reg; /* whoops, do this one again */ | |
364 | end | |
365 | ||
366 | st_read = cur_reg; | |
367 | wr_data = (cur_reg == 4'hF) ? (pc + 12) : st_data; | |
368 | busaddr = raddr; | |
369 | ||
370 | $display("LDMSTM: Stage 2: Writing: regs %b, next_regs %b, reg %d, wr_data %08x, addr %08x", regs, next_regs, cur_reg, wr_data, busaddr); | |
371 | ||
372 | outstall = 1'b1; | |
373 | ||
374 | if(next_regs == 16'b0) begin | |
375 | next_lsm_state = 3'b100; | |
376 | end | |
377 | end | |
378 | 3'b100: begin | |
379 | next_write_reg = insn[21] /* writeback */; | |
380 | next_write_num = insn[19:16]; | |
381 | next_write_data = insn[23] ? op0 + {26'b0, prev_offset} : op0 - {26'b0, prev_offset}; | |
382 | next_lsm_state = 3'b001; | |
383 | $display("LDMSTM: Stage 3: Writing back"); | |
384 | end | |
385 | default: $stop; | |
386 | endcase | |
387 | $display("LDMSTM: Decoded, bubble %d, insn %08x, lsm state %b -> %b, stall %d", inbubble, insn, lsm_state, next_lsm_state, outstall); | |
388 | end | |
389 | `DECODE_LDCSTC: if(!inbubble) begin | |
390 | $display("WARNING: Unimplemented LDCSTC"); | |
391 | end | |
392 | `DECODE_CDP: if(!inbubble) begin | |
393 | cp_req = 1; | |
394 | if (cp_busy) begin | |
395 | outstall = 1; | |
396 | next_outbubble = 1; | |
397 | end | |
398 | if (!cp_ack) begin | |
399 | /* XXX undefined instruction trap */ | |
400 | $display("WARNING: Possible CDP undefined instruction"); | |
401 | end | |
402 | end | |
403 | `DECODE_MRCMCR: if(!inbubble) begin | |
404 | cp_req = 1; | |
405 | cp_rnw = insn[20] /* L */; | |
406 | if (insn[20] == 0 /* store to coprocessor */) | |
407 | cp_write = op0; | |
408 | else begin | |
409 | if (insn[15:12] != 4'hF /* Fuck you ARM */) begin | |
410 | next_write_reg = 1'b1; | |
411 | next_write_num = insn[15:12]; | |
412 | next_write_data = cp_read; | |
413 | end else | |
414 | next_outcpsr = {cp_read[31:28], cpsr[27:0]}; | |
415 | end | |
416 | if (cp_busy) begin | |
417 | outstall = 1; | |
418 | next_outbubble = 1; | |
419 | end | |
420 | if (!cp_ack) begin | |
421 | $display("WARNING: Possible MRCMCR undefined instruction: cp_ack %d, cp_busy %d",cp_ack, cp_busy); | |
422 | end | |
423 | $display("MRCMCR: ack %d, busy %d", cp_ack, cp_busy); | |
424 | end | |
425 | default: begin end | |
426 | endcase | |
427 | ||
428 | if ((flush || delayedflush) && !outstall) | |
429 | next_outbubble = 1'b1; | |
430 | end | |
431 | endmodule |