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1`ifdef SYNTHESIS
2`define lag(x) x
3`else
4`define lag(x) $past(x)
5`endif
6
7module mem
8 ( input bit clk
9 , input bit reset
10
11 , output bit ready
12 , input bit valid
13 , input bit write
14 , input bit [ADDR_BITS-1:0] address
15 , input bit [DATA_BITS-1:0] write_data
16
17 , output bit read_valid
18 , output bit [DATA_BITS-1:0] read_data
19 );
20
21parameter ADDR_BITS;
22parameter DATA_BITS;
23parameter INIT_FILE;
24
25bit [DATA_BITS-1:0] storage [0:(1<<ADDR_BITS)-1];
26initial $readmemh(INIT_FILE, storage);
27
28always_ff @(posedge clk) begin
29 if (reset) begin
30 ready = 0;
31 read_valid = 0;
32 end else begin
33 read_valid = 0;
34 if (ready && `lag(valid)) begin
35 if (`lag(write)) begin
36 storage[`lag(address)] = `lag(write_data);
37 end else begin
38 read_valid = 1;
39 read_data = storage[`lag(address)];
40 end
41 end
42 ready = 1;
43 end
44end
45
46endmodule
47
48module core
49 #( ADDR_BITS = 15
50 , DATA_BITS = 12
51 )
52 ( input bit clk
53 , input bit reset
54
55 , input bit [2:0] switch_df
56 , input bit [2:0] switch_if
57 , input bit [ADDR_BITS-3-1:0] switch_sr
58 , input bit switch_start
59 , input bit switch_load_add
60 , input bit switch_dep
61 , input bit switch_exam
62 , input bit switch_cont
63 , input bit switch_stop
64 , input bit switch_sing_step
65 , input bit switch_sing_inst
66
67 // verilator lint_off UNDRIVEN
68 , output bit [ADDR_BITS-3-1:0] led_pc
69 , output bit [ADDR_BITS-3-1:0] led_memaddr
70 , output bit [DATA_BITS-1:0] led_memdata
71 , output bit [DATA_BITS-1:0] led_acc
72 , output bit [DATA_BITS-1:0] led_mq
73 , output bit led_and
74 , output bit led_tad
75 , output bit led_isz
76 , output bit led_dca
77 , output bit led_jms
78 , output bit led_jmp
79 , output bit led_iot
80 , output bit led_opr
81 , output bit led_fetch
82 , output bit led_execute
83 , output bit led_defer
84 , output bit led_word_count
85 , output bit led_current_address
86 , output bit led_break
87 , output bit led_ion
88 , output bit led_pause
89 , output bit led_run
90 , output bit [4:0] led_step_counter
91 , output bit [2:0] led_df
92 , output bit [2:0] led_if
93 , output bit led_link
94 // verilator lint_on UNDRIVEN
95 );
96
97`ifndef SYNTHESIS
98integer pctrace;
99initial pctrace = $fopen("trace.pcs", "w");
100
101integer eventtrace;
102initial eventtrace = $fopen("trace.events", "r");
103
104// Event trace file format: lines of the form
105// instruction-count skip interrupt
106// Events are triggered before the corresponding instruction
107// Skip opcodes:
108// 0 Do not override skip behaviour of this instruction
109// 1 Force this instruction to "not skip"
110// 2 Force this instruction to "skip"
111// Interrupt opcodes:
112// 0 Do not force an interrupt this instruction
113// 1 Force an interrupt this instruction
114// The first instruction has instruction count 1
115
116integer unsigned nextevent = ~0;
117integer force_skip = 0;
118bit force_interrupt = 0;
119initial if (eventtrace != 0) $fscanf(eventtrace, "%d %d %d", nextevent, force_skip, force_interrupt);
120initial $display("nextevent=%d force_skip=%d force_interrupt=%d", nextevent, force_skip, force_interrupt);
121`endif
122
123bit run;
124bit int_enable;
125bit int_delay;
126bit int_request;
127
128bit switch_start_observed;
129bit switch_load_add_observed;
130bit switch_dep_observed;
131bit switch_exam_observed;
132bit switch_cont_observed;
133
134assign led_run = run;
135assign led_ion = int_enable;
136
137bit mem_ready;
138bit mem_valid;
139bit mem_write;
140bit [ADDR_BITS-1:0] mem_address;
141bit [DATA_BITS-1:0] mem_write_data;
142assign led_current_address = mem_valid;
143
144assign led_memaddr = mem_address[ADDR_BITS-3-1:0];
145
146bit mem_read_valid;
147bit [DATA_BITS-1:0] mem_read_data;
148
149mem
150 #( .ADDR_BITS(ADDR_BITS)
151 , .DATA_BITS(DATA_BITS)
152// , .INIT_FILE("mem/focal69.loaded.hex")
153 , .INIT_FILE("build/mem/hello.hex")
154 )
155 memory
156 ( .clk(clk)
157 , .reset(reset)
158
159 , .ready(mem_ready)
160 , .valid(mem_valid)
161 , .address(mem_address)
162 , .write(mem_write)
163 , .write_data(mem_write_data)
164
165 , .read_valid(mem_read_valid)
166 , .read_data(mem_read_data)
167 );
168
169bit rx_ready;
170bit rx_valid;
171bit [7:0] rx_data;
172
173bit tx_ready;
174bit tx_valid;
175bit [7:0] tx_data;
176
177alt_jtag_atlantic
178 #( .INSTANCE_ID(1)
179 , .LOG2_RXFIFO_DEPTH(6)
180 , .LOG2_TXFIFO_DEPTH(6)
181 , .SLD_AUTO_INSTANCE_INDEX("NO")
182 ) uart
183 ( .clk(clk)
184 , .rst_n(!reset)
185
186 , .r_dat(tx_data)
187 , .r_val(tx_valid)
188 , .r_ena(tx_ready)
189
190 , .t_dat(rx_data)
191 , .t_dav(rx_data)
192 , .t_ena(rx_valid)
193 );
194
195bit [ADDR_BITS-3-1:7] page;
196
197bit [2:0] data_field;
198bit [2:0] data_field_saved;
199bit [2:0] inst_field;
200bit [2:0] inst_field_buffer;
201bit [2:0] inst_field_saved;
202bit [ADDR_BITS-3-1:0] pc;
203bit [ADDR_BITS-3-1:0] next_pc;
204assign led_pc = pc;
205bit [2:0] opcode;
206bit [8:0] operand;
207bit [DATA_BITS-1:0] acc;
208bit link;
209
210assign led_df = data_field;
211assign led_if = inst_field;
212
213assign led_acc = acc;
214assign led_link = link;
215
216assign led_and = opcode == 0;
217assign led_tad = opcode == 1;
218assign led_isz = opcode == 2;
219assign led_dca = opcode == 3;
220assign led_jms = opcode == 4;
221assign led_jmp = opcode == 5;
222assign led_iot = opcode == 6;
223assign led_opr = opcode == 7;
224
225bit tti_int_enable;
226bit tti_valid;
227bit [DATA_BITS-1:0] tti_data;
228
229bit [15:0] tto_delay;
230bit tto_int_enable;
231bit tto_flag;
232bit tto_flag_old;
233
234bit i;
235bit z;
236bit [6:0] wip;
237bit [ADDR_BITS-1:0] address;
238
239bit can_skip;
240bit skip;
241bit injected_instruction;
242
243`ifndef SYNTHESIS
244integer unsigned instcount = 1;
245`endif
246
247assign int_request = 0
248 || (tti_int_enable && tti_valid)
249 || (tto_int_enable && tto_flag && !tto_flag_old)
250 ;
251
252enum
253 { FETCH
254 , DECODE
255 , INDIRECT
256 , INDIRECTED
257 , PREINC
258 , AGEN
259 , EXEC
260 , MEMWAIT
261 , HALT
262 , DEPOSIT
263 , RETIRE
264 } state;
265
266assign led_fetch = state == FETCH;
267assign led_execute = state == DECODE || state == AGEN || state == EXEC;
268assign led_defer = state == INDIRECT || state == INDIRECTED || state == PREINC;
269assign led_pause = state == MEMWAIT || state == HALT;
270
271always_ff @(posedge clk) begin
272 if (reset) begin
273`ifdef SYNTHESIS
274 run = 0;
275`else
276 run = 1;
277`endif
278 int_enable = 0;
279 int_delay = 0;
280 switch_start_observed = 0;
281 switch_load_add_observed = 0;
282 switch_dep_observed = 0;
283 switch_exam_observed = 0;
284 switch_cont_observed = 0;
285 mem_valid = 0;
286 rx_ready = 0;
287 tx_valid = 0;
288 tto_delay = 0;
289 tto_flag = 1;
290 tto_flag_old = 1;
291 tx_data = 0;
292 data_field = 0;
293 data_field_saved = 0;
294 inst_field = 0;
295 inst_field_buffer = 0;
296 inst_field_saved = 0;
297 pc = 'o200;
298 acc = 0;
299 link = 1;
300 tti_int_enable = 1;
301 tto_int_enable = 1;
302 tti_valid = 0;
303 state = state.first;
304 end else begin
305 if (switch_start && !switch_start_observed) begin
306 switch_start_observed = 1;
307 run = 1;
308 int_enable = 0;
309 int_delay = 0;
310 mem_valid = 0;
311 acc = 0;
312 link = 1;
313 state = state.first;
314 end
315
316 if (!switch_start)
317 switch_start_observed = 0;
318
319 if (switch_load_add && !switch_load_add_observed) begin
320 switch_load_add_observed = 1;
321 data_field = switch_df;
322 inst_field = switch_if;
323 inst_field_buffer = switch_if;
324 pc = switch_sr;
325 end
326
327 if (!switch_load_add)
328 switch_load_add_observed = 0;
329
330`ifdef HISTORIC_SWITCH_BEHAVIOUR
331 if (switch_dep)
332 switch_dep_observed = 1;
333
334 if (!switch_dep && switch_dep_observed) begin
335`else
336 if (switch_dep && !switch_dep_observed) begin
337 switch_dep_observed = 1;
338`endif
339 state = DEPOSIT;
340 mem_valid = 1;
341 mem_address = {inst_field, pc};
342 mem_write = 1;
343 mem_write_data = switch_sr;
344 led_memdata = mem_write_data;
345 run = 1;
346 end
347
348 if (!switch_dep)
349 switch_dep_observed = 0;
350
351 if (switch_exam && !switch_exam_observed) begin
352 if (!run) begin
353 switch_exam_observed = 1;
354 state = FETCH;
355 run = 1;
356 end
357 end
358
359 if (!switch_exam)
360 switch_exam_observed = 0;
361
362 if (switch_cont && !switch_cont_observed) begin
363 switch_cont_observed = 1;
364 run = 1;
365 end
366
367 if (!switch_cont)
368 switch_cont_observed = 0;
369
370 if (switch_stop)
371 run = 0;
372
373 if (`lag(tx_ready)) begin
374 if (tx_valid)
375 tto_flag = 1;
376 tx_valid = 0;
377 end
378 if (tto_delay == 1)
379 tx_valid = 1;
380 if (tto_delay != 0)
381 --tto_delay;
382 if (rx_ready && `lag(rx_valid)) begin
383 tti_valid = 1;
384 tti_data = {4'b0, 1'b1, `lag(rx_data[6:0])};
385 if (tti_data[6:0] == 7'h0a)
386 tti_data[6:0] = 7'h0d;
387 else if (tti_data[6:0] == 7'h1b)
388 tti_data[6:0] = 7'h03;
389 end
390
391 if (run) begin
392 case (state)
393 FETCH: begin
394 can_skip = 0;
395 skip = 0;
396 injected_instruction = 0;
397 mem_valid = 1;
398 mem_address = {inst_field, pc};
399 mem_write = 0;
400 if (`lag(mem_ready)) begin
401 state = DECODE;
402 page = pc[ADDR_BITS-3-1:7];
403 next_pc = pc + 1;
404 end
405 end
406
407 DECODE: begin
408 automatic bit go;
409 go = 0;
410 mem_valid = 0;
411 mem_write = 0;
412`ifdef SYNTHESIS
413 if (!switch_exam_observed && (int_enable && int_request)) begin
414`else
415 if (!switch_exam_observed && ((nextevent == ~0 && int_enable && int_request) || (instcount == nextevent && force_interrupt))) begin
416 if (! int_enable)
417 $display("ERROR: forced interrupt at a point where architecturally interrupts are disabled");
418`endif
419 $display("taking interrupt at instcount=%d", instcount);
420 int_enable = 0;
421 int_delay = 0;
422 data_field_saved = data_field;
423 inst_field_saved = inst_field;
424 data_field = 0;
425 inst_field = 0;
426 inst_field_buffer = 0;
427 tto_flag_old = tto_flag;
428 opcode = 'o4;
429 operand = 'o000;
430 next_pc = pc;
431 injected_instruction = 1;
432 go = 1;
433 end else if (`lag(mem_read_valid)) begin
434 state = RETIRE;
435 led_memdata = `lag(mem_read_data);
436 {opcode, operand} = `lag(mem_read_data);
437 if (switch_exam_observed) begin
438 run = 0;
439 end else begin
440 go = 1;
441 end
442 end
443 if (go) begin
444 int_enable = int_delay;
445 {i, z, wip} = operand;
446 if (z)
447 address = {inst_field, page, wip};
448 else
449 address = {inst_field, 5'b0, wip};
450 $display("%d %o: %o%o", instcount, pc, opcode, operand);
451 case (opcode)
452 'o0, 'o1, 'o2: state = i ? INDIRECT : AGEN;
453 'o3, 'o4: state = i ? INDIRECT : EXEC;
454 'o5: begin
455 if (i) begin
456 state = INDIRECT;
457 end else begin
458 next_pc = address[ADDR_BITS-3-1:0];
459 inst_field = inst_field_buffer;
460 end
461 end
462 'o7: begin
463 casez (operand)
464 'b0????????: begin
465 automatic bit cla, cll, cma, cml, rar, ral, bsw, iac;
466 {cla, cll, cma, cml, rar, ral, bsw, iac} = operand[7:0];
467 if (cla) acc = 0;
468 if (cll) link = 0;
469 if (cma) acc = ~acc;
470 if (cml) link = ~link;
471 if (iac) {link, acc} += 1;
472 if (rar && !ral) begin
473 {link, acc} = {acc[0], link, acc[11:1]};
474 if (bsw) {link, acc} = {acc[0], link, acc[11:1]};
475 end
476 if (ral && !rar) begin
477 {link, acc} = {acc, link};
478 if (bsw) {link, acc} = {acc, link};
479 end
480 if (bsw && !(rar || ral)) acc = {acc[5:0], acc[11:6]};
481 end
482 'b1????0??0: begin
483 automatic bit cla, sma, sza, snl, osr, hlt;
484 can_skip = 1;
485 {cla, sma, sza, snl, osr, hlt} = {operand[7:4], operand[2:1]};
486 if (sma && acc[11]) skip = 1;
487 if (sza && acc == 0) skip = 1;
488 if (snl && link != 0) skip = 1;
489 if (cla) acc = 0;
490 if (osr) begin
491 $display("%o: unsupported front panel switch test", pc);
492 $finish;
493 end
494 if (hlt) state = HALT;
495 end
496 'b1????1??0: begin
497 automatic bit cla, spa, sna, szl, osr, hlt;
498 can_skip = 1;
499 skip = 1;
500 {cla, spa, sna, szl, osr, hlt} = {operand[7:4], operand[2:1]};
501 if (spa && acc[11]) skip = 0;
502 if (sna && acc == 0) skip = 0;
503 if (szl && link != 0) skip = 0;
504 if (cla) acc = 0;
505 if (osr) begin
506 $display("%o: unsupported front panel switch test", pc);
507 $finish;
508 end
509 if (hlt) state = HALT;
510 end
511 default: begin
512 $display("%o: decoded unknown opcode %o %o", pc, opcode, operand);
513 $finish;
514 end
515 endcase
516 end
517 'o6: begin
518 case (operand[8:6])
519 'o0: begin
520 case (operand[5:3])
521 'o0: begin
522 case (operand[2:0])
523 'o0: begin
524 can_skip = 1;
525 if (int_enable)
526 skip = 1;
527 int_enable = 0;
528 int_delay = 0;
529 end
530 'o1: int_delay = 1;
531 'o2: begin
532 int_enable = 0;
533 int_delay = 0;
534 end
535 'o3: begin
536 can_skip = 1;
537 if (int_request)
538 skip = 1;
539 end
540 'o4: acc = {link, 1'b0/*gt*/, int_request, 1'b0/*ii*/, int_enable, 1'b0/*u*/, 3'b0/*if*/, 3'b0/*df*/};
541 'o5: begin
542 link = acc[11];
543 if (acc[7]) begin
544 int_delay = 1;
545 end else begin
546 int_enable = 0;
547 int_delay = 0;
548 end
549 end
550 'o7: begin
551 int_enable = 0;
552 int_delay = 0;
553 acc = 0;
554 link = 1;
555 tx_valid = 0;
556 tto_flag = 1;
557 tto_flag_old = 1;
558 tti_valid = 0;
559 end
560 default: $display("%o: unsupported 600%o op", pc, operand[2:0]);
561 endcase
562 end
563 'o3: begin
564 case (operand[2:0])
565 'o0: tti_valid = 0;
566 'o1: begin
567 can_skip = 1;
568 if (tti_valid) skip = 1;
569 end
570 'o2: begin
571 acc = 0;
572 tti_valid = 0;
573 end
574 'o4: begin
575 acc |= tti_data;
576 end
577 'o5: begin
578 tti_int_enable = acc[0];
579 end
580 'o6: begin
581 acc = tti_data;
582 tti_valid = 0;
583 end
584 default: begin
585 $display("%o: unsupported keyboard op %o", pc, operand[2:0]);
586 $finish;
587 end
588 endcase
589 end
590 'o4: begin
591 case (operand[2:0])
592 'o0: begin
593 tto_flag = 1;
594 tto_flag_old = 1;
595 end
596 'o1: begin
597 can_skip = 1;
598 if (tto_flag) skip = 1;
599 end
600 'o2: begin
601 tto_flag = 0;
602 tto_flag_old = 0;
603 end
604 'o4: begin
605 tto_delay = 100;
606 $display("[%o] write %o", pc, acc[6:0]);
607 tx_data = {1'b0, acc[6:0]};
608 if (tx_data == 'h8d)
609 tx_data = 'h8a;
610 end
611 'o5: begin
612 can_skip = 1;
613 if (tto_flag || tti_valid) skip = 1;
614 end
615 'o6: begin
616 tto_delay =100;
617 tto_flag = 0;
618 tto_flag_old = 0;
619 $display("[%o] write %o", pc, acc[6:0]);
620 tx_data = {1'b0, acc[6:0]};
621 if (tx_data == 'h8d)
622 tx_data = 'h8a;
623 end
624 default: begin
625 $display("%o: unsupported tty op %o", pc, operand[2:0]);
626 $finish;
627 end
628 endcase
629 end
630 default: begin
631 $display("%o: unsupported device %o (operation %o)", pc, operand[8:3], operand[2:0]);
632 can_skip = 1;
633 end
634 endcase
635 end
636 'o2: begin
637 if (operand[0])
638 data_field = operand[5:3];
639 if (operand[1])
640 inst_field_buffer = operand[5:3];
641 if (operand[2]) begin
642 if (operand[3] && operand[4])
643 acc = acc | {6'b0, inst_field_saved, data_field_saved};
644 else if (operand[3])
645 acc = acc | {6'b0, data_field, 3'b0};
646 else if (operand[4])
647 acc = acc | {6'b0, inst_field, 3'b0};
648 if (operand[5]) begin
649 data_field = data_field_saved;
650 inst_field_buffer = inst_field_saved;
651 end
652 end
653 end
654 default: begin
655 $display("%o: unsupported device %o (operation %o)", pc, operand[8:3], operand[2:0]);
656 can_skip = 1;
657 end
658 endcase
659 end
660 default: begin
661 $display("%o: decoded unknown opcode %o %o", pc, opcode, operand);
662 $finish;
663 end
664 endcase
665 end
666 end
667
668 INDIRECT: begin
669 mem_valid = 1;
670 mem_write = 0;
671 mem_address = address;
672 state = `lag(mem_ready) ? INDIRECTED : INDIRECT;
673 end
674
675 INDIRECTED: begin
676 if (`lag(mem_ready)) begin
677 mem_valid = 0;
678 mem_write = 0;
679 end
680 if (`lag(mem_read_valid)) begin
681 if (opcode != 'o5 && address[7:3] == 5'b00001) begin
682 led_memdata = `lag(mem_read_data);
683 address = {3'b0, `lag(mem_read_data)};
684 address += 1;
685 address[ADDR_BITS-1:ADDR_BITS-3] = data_field;
686 state = PREINC;
687 end else begin
688 led_memdata = `lag(mem_read_data);
689 address = {data_field, `lag(mem_read_data)};
690 case (opcode)
691 'o0, 'o1, 'o2: state = AGEN;
692 'o3, 'o4: state = EXEC;
693 'o5: begin
694 next_pc = address[ADDR_BITS-3-1:0];
695 $display("indirect jump to %o", next_pc);
696 inst_field = inst_field_buffer;
697 state = RETIRE;
698 end
699 endcase
700 end
701 end
702 end
703
704 PREINC: begin
705 mem_valid = 1;
706 mem_write = 1;
707 mem_write_data = address[DATA_BITS-1:0];
708 led_memdata = mem_write_data;
709 $display("preinc [%o] <- %o", mem_address, mem_write_data);
710 case (opcode)
711 'o0, 'o1, 'o2: state = `lag(mem_ready) ? AGEN : PREINC;
712 'o3, 'o4, 'o5: state = `lag(mem_ready) ? EXEC : PREINC;
713 endcase
714 end
715
716 AGEN: begin
717 mem_valid = 1;
718 case (opcode)
719 'o0, 'o1, 'o2: mem_write = 0;
720 endcase
721 mem_address = address;
722 state = `lag(mem_ready) ? EXEC : AGEN;
723 end
724
725 EXEC: begin
726 automatic bit stall = 0;
727 if (`lag(mem_ready)) begin
728 mem_valid = 0;
729 mem_write = 0;
730 end else if (mem_valid) begin
731 stall = 1;
732 end
733 case (opcode)
734 'o0, 'o1, 'o2: if (! `lag(mem_read_valid)) stall = 1;
735 endcase
736 if (! stall) begin
737 state = RETIRE;
738 case (opcode)
739 'o0: begin led_memdata = `lag(mem_read_data); acc &= `lag(mem_read_data); end
740 'o1: begin led_memdata = `lag(mem_read_data); {link, acc} += {1'b0, `lag(mem_read_data)}; end
741 'o2: begin
742 mem_valid = 1;
743 mem_address = address;
744 mem_write = 1;
745 mem_write_data = `lag(mem_read_data) + 1;
746 led_memdata = mem_write_data;
747 $display("store [%o] <- %o", mem_address, mem_write_data);
748 can_skip = 1;
749 if (mem_write_data == 0) skip = 1;
750 state = MEMWAIT;
751 end
752 'o3: begin
753 mem_valid = 1;
754 mem_address = address;
755 mem_write = 1;
756 mem_write_data = acc;
757 led_memdata = mem_write_data;
758 $display("store [%o] <- %o", mem_address, mem_write_data);
759 acc = 0;
760 state = MEMWAIT;
761 end
762 'o4: begin
763 mem_valid = 1;
764 mem_address = address;
765 mem_write = 1;
766 mem_write_data = next_pc[DATA_BITS-1:0];
767 led_memdata = mem_write_data;
768 $display("store [%o] <- %o", mem_address, mem_write_data);
769 next_pc = address[ADDR_BITS-3-1:0] + 1;
770 inst_field = inst_field_buffer;
771 state = MEMWAIT;
772 end
773 'o5: begin
774 next_pc = address[ADDR_BITS-3-1:0];
775 inst_field = inst_field_buffer;
776 end
777 endcase
778 end
779 end
780
781 MEMWAIT: state = `lag(mem_ready) ? RETIRE : MEMWAIT;
782
783 HALT: begin
784 run = 0;
785 $display("\nhalt state reached");
786 $finish;
787 end
788
789 DEPOSIT: begin
790 if (`lag(mem_ready)) begin
791 state = FETCH; // Not a retired instruction; go directly to decode
792 page = pc[ADDR_BITS-3-1:7];
793 ++pc; // Not a skip; normal part of panel deposit (because we are skipping RETIRE)
794 run = 0;
795 end
796 end
797 endcase
798
799 if (state == RETIRE) begin
800`ifndef SYNTHESIS
801 if (!injected_instruction) begin
802 $display("retiring pc=%o%o", inst_field, pc);
803 $fdisplay(pctrace, "%o%o", inst_field, pc);
804 end
805`endif
806
807 state = FETCH;
808 pc = next_pc;
809
810 if (can_skip) begin
811`ifndef SYNTHESIS
812 if (instcount == nextevent) begin
813 $display("checking instcount=%d force_skip=%d against inferred skip=%d", instcount, force_skip, skip);
814 if (force_skip == 1)
815 skip = 0;
816 else if (force_skip == 2)
817 skip = 1;
818 end
819`endif
820 if (skip) begin
821 $display("skip at instcount=%d pc=%o", instcount, pc);
822 ++pc;
823 end
824 end
825`ifndef SYNTHESIS
826 else if (instcount == nextevent && force_skip != 0) begin
827 $display("Error: forced skip at impossible boundary instcount=%d nextpc=%o", instcount, pc);
828 $finish;
829 end
830`endif
831
832`ifndef SYNTHESIS
833 if (instcount == nextevent) begin
834 nextevent = ~0;
835 if (eventtrace != 0) $fscanf(eventtrace, "%d %d %d", nextevent, force_skip, force_interrupt);
836 $display("nextevent=%d force_skip=%d force_interrupt=%d", nextevent, force_skip, force_interrupt);
837 end
838 if (!injected_instruction) begin
839 ++instcount;
840 if (instcount >= 26000) $finish;
841 end
842`endif
843 end
844
845 if (switch_sing_step)
846 run = 0;
847
848 if (state == FETCH && switch_sing_inst)
849 run = 0;
850
851 rx_ready = !tti_valid;
852 end
853 end
854end
855
856endmodule
generated by cgit v1.2.3 (git 2.51.0) at 2026-04-19 00:49:22 -0700