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-rw-r--r--hdl/core.sv246
-rw-r--r--hdl/jtag_uart.sv21
2 files changed, 219 insertions, 48 deletions
diff --git a/hdl/core.sv b/hdl/core.sv
index 34a1e44..2e278f3 100644
--- a/hdl/core.sv
+++ b/hdl/core.sv
@@ -49,6 +49,32 @@ module core
49 // verilator lint_on UNDRIVEN 49 // verilator lint_on UNDRIVEN
50 ); 50 );
51 51
52`ifndef SYNTHESIS
53integer pctrace;
54initial pctrace = $fopen("trace.pcs", "w");
55
56integer eventtrace;
57initial eventtrace = $fopen("trace.events", "r");
58
59// Event trace file format: lines of the form
60// instruction-count skip interrupt
61// Events are triggered before the corresponding instruction
62// Skip opcodes:
63// 0 Do not override skip behaviour of this instruction
64// 1 Force this instruction to "not skip"
65// 2 Force this instruction to "skip"
66// Interrupt opcodes:
67// 0 Do not force an interrupt this instruction
68// 1 Force an interrupt this instruction
69// The first instruction has instruction count 1
70
71integer unsigned nextevent = ~0;
72integer force_skip = 0;
73bit force_interrupt = 0;
74initial if (eventtrace != 0) $fscanf(eventtrace, "%d %d %d", nextevent, force_skip, force_interrupt);
75initial $display("nextevent=%d force_skip=%d force_interrupt=%d", nextevent, force_skip, force_interrupt);
76`endif
77
52bit run; 78bit run;
53bit int_enable; 79bit int_enable;
54bit int_delay; 80bit int_delay;
@@ -126,6 +152,7 @@ bit [2:0] inst_field;
126bit [2:0] inst_field_buffer; 152bit [2:0] inst_field_buffer;
127bit [2:0] inst_field_saved; 153bit [2:0] inst_field_saved;
128bit [ADDR_BITS-3-1:0] pc; 154bit [ADDR_BITS-3-1:0] pc;
155bit [ADDR_BITS-3-1:0] next_pc;
129assign led_pc = pc; 156assign led_pc = pc;
130bit [2:0] opcode; 157bit [2:0] opcode;
131bit [8:0] operand; 158bit [8:0] operand;
@@ -151,13 +178,27 @@ bit tti_int_enable;
151bit tti_valid; 178bit tti_valid;
152bit [DATA_BITS-1:0] tti_data; 179bit [DATA_BITS-1:0] tti_data;
153 180
181bit [15:0] tto_delay;
182bit tto_int_enable;
183bit tto_flag;
184bit tto_flag_old;
185
154bit i; 186bit i;
155bit z; 187bit z;
156bit [6:0] wip; 188bit [6:0] wip;
157bit [ADDR_BITS-1:0] address; 189bit [ADDR_BITS-1:0] address;
158 190
159assign int_request = 191bit can_skip;
160 (tti_int_enable && tti_valid) 192bit skip;
193bit injected_instruction;
194
195`ifndef SYNTHESIS
196integer unsigned instcount = 1;
197`endif
198
199assign int_request = 0
200 || (tti_int_enable && tti_valid)
201 || (tto_int_enable && tto_flag && !tto_flag_old)
161 ; 202 ;
162 203
163enum 204enum
@@ -171,6 +212,7 @@ enum
171 , MEMWAIT 212 , MEMWAIT
172 , HALT 213 , HALT
173 , DEPOSIT 214 , DEPOSIT
215 , RETIRE
174 } state; 216 } state;
175 217
176assign led_fetch = state == FETCH; 218assign led_fetch = state == FETCH;
@@ -195,6 +237,9 @@ always_ff @(posedge clk) begin
195 mem_valid = 0; 237 mem_valid = 0;
196 rx_ready = 0; 238 rx_ready = 0;
197 tx_valid = 0; 239 tx_valid = 0;
240 tto_delay = 0;
241 tto_flag = 1;
242 tto_flag_old = 1;
198 tx_data = 0; 243 tx_data = 0;
199 data_field = 0; 244 data_field = 0;
200 data_field_saved = 0; 245 data_field_saved = 0;
@@ -204,7 +249,8 @@ always_ff @(posedge clk) begin
204 pc = 'o200; 249 pc = 'o200;
205 acc = 0; 250 acc = 0;
206 link = 1; 251 link = 1;
207 tti_int_enable = 0; 252 tti_int_enable = 1;
253 tto_int_enable = 1;
208 tti_valid = 0; 254 tti_valid = 0;
209 state = state.first; 255 state = state.first;
210 end else begin 256 end else begin
@@ -276,22 +322,37 @@ always_ff @(posedge clk) begin
276 if (switch_stop) 322 if (switch_stop)
277 run = 0; 323 run = 0;
278 324
279 if (`lag(tx_ready)) tx_valid = 0; 325 if (`lag(tx_ready)) begin
326 if (tx_valid)
327 tto_flag = 1;
328 tx_valid = 0;
329 end
330 if (tto_delay == 1)
331 tx_valid = 1;
332 if (tto_delay != 0)
333 --tto_delay;
280 if (rx_ready && `lag(rx_valid)) begin 334 if (rx_ready && `lag(rx_valid)) begin
281 tti_valid = 1; 335 tti_valid = 1;
282 tti_data = {4'b0, 1'b1, `lag(rx_data[6:0])}; 336 tti_data = {4'b0, 1'b1, `lag(rx_data[6:0])};
337 if (tti_data[6:0] == 7'h0a)
338 tti_data[6:0] = 7'h0d;
339 else if (tti_data[6:0] == 7'h1b)
340 tti_data[6:0] = 7'h03;
283 end 341 end
284 342
285 if (run) begin 343 if (run) begin
286 case (state) 344 case (state)
287 FETCH: begin 345 FETCH: begin
346 can_skip = 0;
347 skip = 0;
348 injected_instruction = 0;
288 mem_valid = 1; 349 mem_valid = 1;
289 mem_address = {inst_field, pc}; 350 mem_address = {inst_field, pc};
290 mem_write = 0; 351 mem_write = 0;
291 if (`lag(mem_ready)) begin 352 if (`lag(mem_ready)) begin
292 state = DECODE; 353 state = DECODE;
293 page = pc[ADDR_BITS-3-1:7]; 354 page = pc[ADDR_BITS-3-1:7];
294 ++pc; 355 next_pc = pc + 1;
295 end 356 end
296 end 357 end
297 358
@@ -300,7 +361,14 @@ always_ff @(posedge clk) begin
300 go = 0; 361 go = 0;
301 mem_valid = 0; 362 mem_valid = 0;
302 mem_write = 0; 363 mem_write = 0;
364`ifdef SYNTHESIS
303 if (!switch_exam_observed && (int_enable && int_request)) begin 365 if (!switch_exam_observed && (int_enable && int_request)) begin
366`else
367 if (!switch_exam_observed && ((nextevent == ~0 && int_enable && int_request) || (instcount == nextevent && force_interrupt))) begin
368 if (! int_enable)
369 $display("ERROR: forced interrupt at a point where architecturally interrupts are disabled");
370`endif
371 $display("taking interrupt at instcount=%d", instcount);
304 int_enable = 0; 372 int_enable = 0;
305 int_delay = 0; 373 int_delay = 0;
306 data_field_saved = data_field; 374 data_field_saved = data_field;
@@ -308,12 +376,14 @@ always_ff @(posedge clk) begin
308 data_field = 0; 376 data_field = 0;
309 inst_field = 0; 377 inst_field = 0;
310 inst_field_buffer = 0; 378 inst_field_buffer = 0;
311 --pc; 379 tto_flag_old = tto_flag;
312 opcode = 'b100; 380 opcode = 'o4;
313 operand = 'b000000000; 381 operand = 'o000;
382 next_pc = pc;
383 injected_instruction = 1;
314 go = 1; 384 go = 1;
315 end else if (`lag(mem_read_valid)) begin 385 end else if (`lag(mem_read_valid)) begin
316 state = FETCH; 386 state = RETIRE;
317 led_memdata = `lag(mem_read_data); 387 led_memdata = `lag(mem_read_data);
318 {opcode, operand} = `lag(mem_read_data); 388 {opcode, operand} = `lag(mem_read_data);
319 if (switch_exam_observed) begin 389 if (switch_exam_observed) begin
@@ -324,15 +394,12 @@ always_ff @(posedge clk) begin
324 end 394 end
325 if (go) begin 395 if (go) begin
326 int_enable = int_delay; 396 int_enable = int_delay;
327 // $display("%o: decode %o %o", pc-1, opcode, operand);
328 // verilator lint_off WIDTH
329 // $display("%o %b %o 0000", 14'(pc-1), link, acc);
330 // verilator lint_on WIDTH
331 {i, z, wip} = operand; 397 {i, z, wip} = operand;
332 if (z) 398 if (z)
333 address = {inst_field, page, wip}; 399 address = {inst_field, page, wip};
334 else 400 else
335 address = {inst_field, 5'b0, wip}; 401 address = {inst_field, 5'b0, wip};
402 $display("%d %o: %o%o", instcount, pc, opcode, operand);
336 case (opcode) 403 case (opcode)
337 'o0, 'o1, 'o2: state = i ? INDIRECT : AGEN; 404 'o0, 'o1, 'o2: state = i ? INDIRECT : AGEN;
338 'o3, 'o4: state = i ? INDIRECT : EXEC; 405 'o3, 'o4: state = i ? INDIRECT : EXEC;
@@ -340,7 +407,7 @@ always_ff @(posedge clk) begin
340 if (i) begin 407 if (i) begin
341 state = INDIRECT; 408 state = INDIRECT;
342 end else begin 409 end else begin
343 pc = address[ADDR_BITS-3-1:0]; 410 next_pc = address[ADDR_BITS-3-1:0];
344 inst_field = inst_field_buffer; 411 inst_field = inst_field_buffer;
345 end 412 end
346 end 413 end
@@ -366,13 +433,11 @@ always_ff @(posedge clk) begin
366 end 433 end
367 'b1????0??0: begin 434 'b1????0??0: begin
368 automatic bit cla, sma, sza, snl, osr, hlt; 435 automatic bit cla, sma, sza, snl, osr, hlt;
369 automatic bit skip; 436 can_skip = 1;
370 {cla, sma, sza, snl, osr, hlt} = {operand[7:4], operand[2:1]}; 437 {cla, sma, sza, snl, osr, hlt} = {operand[7:4], operand[2:1]};
371 skip = 0;
372 if (sma && acc[11]) skip = 1; 438 if (sma && acc[11]) skip = 1;
373 if (sza && acc == 0) skip = 1; 439 if (sza && acc == 0) skip = 1;
374 if (snl && link != 0) skip = 1; 440 if (snl && link != 0) skip = 1;
375 if (skip) pc++;
376 if (cla) acc = 0; 441 if (cla) acc = 0;
377 if (osr) begin 442 if (osr) begin
378 $display("%o: unsupported front panel switch test", pc); 443 $display("%o: unsupported front panel switch test", pc);
@@ -382,13 +447,12 @@ always_ff @(posedge clk) begin
382 end 447 end
383 'b1????1??0: begin 448 'b1????1??0: begin
384 automatic bit cla, spa, sna, szl, osr, hlt; 449 automatic bit cla, spa, sna, szl, osr, hlt;
385 automatic bit skip; 450 can_skip = 1;
386 {cla, spa, sna, szl, osr, hlt} = {operand[7:4], operand[2:1]};
387 skip = 1; 451 skip = 1;
452 {cla, spa, sna, szl, osr, hlt} = {operand[7:4], operand[2:1]};
388 if (spa && acc[11]) skip = 0; 453 if (spa && acc[11]) skip = 0;
389 if (sna && acc == 0) skip = 0; 454 if (sna && acc == 0) skip = 0;
390 if (szl && link != 0) skip = 0; 455 if (szl && link != 0) skip = 0;
391 if (skip) pc++;
392 if (cla) acc = 0; 456 if (cla) acc = 0;
393 if (osr) begin 457 if (osr) begin
394 $display("%o: unsupported front panel switch test", pc); 458 $display("%o: unsupported front panel switch test", pc);
@@ -397,7 +461,7 @@ always_ff @(posedge clk) begin
397 if (hlt) state = HALT; 461 if (hlt) state = HALT;
398 end 462 end
399 default: begin 463 default: begin
400 $display("%o: decoded unknown opcode %o %o", pc-1, opcode, operand); 464 $display("%o: decoded unknown opcode %o %o", pc, opcode, operand);
401 $finish; 465 $finish;
402 end 466 end
403 endcase 467 endcase
@@ -409,8 +473,9 @@ always_ff @(posedge clk) begin
409 'o0: begin 473 'o0: begin
410 case (operand[2:0]) 474 case (operand[2:0])
411 'o0: begin 475 'o0: begin
476 can_skip = 1;
412 if (int_enable) 477 if (int_enable)
413 ++pc; 478 skip = 1;
414 int_enable = 0; 479 int_enable = 0;
415 int_delay = 0; 480 int_delay = 0;
416 end 481 end
@@ -420,8 +485,9 @@ always_ff @(posedge clk) begin
420 int_delay = 0; 485 int_delay = 0;
421 end 486 end
422 'o3: begin 487 'o3: begin
488 can_skip = 1;
423 if (int_request) 489 if (int_request)
424 ++pc; 490 skip = 1;
425 end 491 end
426 'o4: acc = {link, 1'b0/*gt*/, int_request, 1'b0/*ii*/, int_enable, 1'b0/*u*/, 3'b0/*if*/, 3'b0/*df*/}; 492 'o4: acc = {link, 1'b0/*gt*/, int_request, 1'b0/*ii*/, int_enable, 1'b0/*u*/, 3'b0/*if*/, 3'b0/*df*/};
427 'o5: begin 493 'o5: begin
@@ -439,14 +505,27 @@ always_ff @(posedge clk) begin
439 acc = 0; 505 acc = 0;
440 link = 1; 506 link = 1;
441 tx_valid = 0; 507 tx_valid = 0;
508 tto_flag = 1;
509 tto_flag_old = 1;
442 tti_valid = 0; 510 tti_valid = 0;
443 end 511 end
444 default: $display("%o: unsupported 600%o op", pc-1, operand[2:0]); 512 default: $display("%o: unsupported 600%o op", pc, operand[2:0]);
445 endcase 513 endcase
446 end 514 end
447 'o3: begin 515 'o3: begin
448 case (operand[2:0]) 516 case (operand[2:0])
449 'o1: if (tti_valid) pc++; 517 'o0: tti_valid = 0;
518 'o1: begin
519 can_skip = 1;
520 if (tti_valid) skip = 1;
521 end
522 'o2: begin
523 acc = 0;
524 tti_valid = 0;
525 end
526 'o4: begin
527 acc |= tti_data;
528 end
450 'o5: begin 529 'o5: begin
451 tti_int_enable = acc[0]; 530 tti_int_enable = acc[0];
452 end 531 end
@@ -455,26 +534,54 @@ always_ff @(posedge clk) begin
455 tti_valid = 0; 534 tti_valid = 0;
456 end 535 end
457 default: begin 536 default: begin
458 $display("%o: unsupported keyboard op %o", pc-1, operand[2:0]); 537 $display("%o: unsupported keyboard op %o", pc, operand[2:0]);
459 $finish; 538 $finish;
460 end 539 end
461 endcase 540 endcase
462 end 541 end
463 'o4: begin 542 'o4: begin
464 case (operand[2:0]) 543 case (operand[2:0])
465 'o1: if (!tx_valid) pc++; 544 'o0: begin
545 tto_flag = 1;
546 tto_flag_old = 1;
547 end
548 'o1: begin
549 can_skip = 1;
550 if (tto_flag) skip = 1;
551 end
552 'o2: begin
553 tto_flag = 0;
554 tto_flag_old = 0;
555 end
556 'o4: begin
557 tto_delay = 100;
558 $display("[%o] write %o", pc, acc[6:0]);
559 tx_data = {1'b0, acc[6:0]};
560 if (tx_data == 'h8d)
561 tx_data = 'h8a;
562 end
563 'o5: begin
564 can_skip = 1;
565 if (tto_flag || tti_valid) skip = 1;
566 end
466 'o6: begin 567 'o6: begin
467 tx_valid = 1; 568 tto_delay =100;
569 tto_flag = 0;
570 tto_flag_old = 0;
571 $display("[%o] write %o", pc, acc[6:0]);
468 tx_data = {1'b0, acc[6:0]}; 572 tx_data = {1'b0, acc[6:0]};
573 if (tx_data == 'h8d)
574 tx_data = 'h8a;
469 end 575 end
470 default: begin 576 default: begin
471 $display("%o: unsupported tty op %o", pc-1, operand[2:0]); 577 $display("%o: unsupported tty op %o", pc, operand[2:0]);
472 $finish; 578 $finish;
473 end 579 end
474 endcase 580 endcase
475 end 581 end
476 default: begin 582 default: begin
477 $display("%o: unsupported device %o (operation %o)", pc-1, operand[8:3], operand[2:0]); 583 $display("%o: unsupported device %o (operation %o)", pc, operand[8:3], operand[2:0]);
584 can_skip = 1;
478 end 585 end
479 endcase 586 endcase
480 end 587 end
@@ -497,12 +604,13 @@ always_ff @(posedge clk) begin
497 end 604 end
498 end 605 end
499 default: begin 606 default: begin
500 $display("%o: unsupported device %o (operation %o)", pc-1, operand[8:3], operand[2:0]); 607 $display("%o: unsupported device %o (operation %o)", pc, operand[8:3], operand[2:0]);
608 can_skip = 1;
501 end 609 end
502 endcase 610 endcase
503 end 611 end
504 default: begin 612 default: begin
505 $display("%o: decoded unknown opcode %o %o", pc-1, opcode, operand); 613 $display("%o: decoded unknown opcode %o %o", pc, opcode, operand);
506 $finish; 614 $finish;
507 end 615 end
508 endcase 616 endcase
@@ -522,7 +630,7 @@ always_ff @(posedge clk) begin
522 mem_write = 0; 630 mem_write = 0;
523 end 631 end
524 if (`lag(mem_read_valid)) begin 632 if (`lag(mem_read_valid)) begin
525 if (address[7:3] == 5'b00001) begin 633 if (opcode != 'o5 && address[7:3] == 5'b00001) begin
526 led_memdata = `lag(mem_read_data); 634 led_memdata = `lag(mem_read_data);
527 address = {3'b0, `lag(mem_read_data)}; 635 address = {3'b0, `lag(mem_read_data)};
528 address += 1; 636 address += 1;
@@ -535,9 +643,10 @@ always_ff @(posedge clk) begin
535 'o0, 'o1, 'o2: state = AGEN; 643 'o0, 'o1, 'o2: state = AGEN;
536 'o3, 'o4: state = EXEC; 644 'o3, 'o4: state = EXEC;
537 'o5: begin 645 'o5: begin
538 pc = address[ADDR_BITS-3-1:0]; 646 next_pc = address[ADDR_BITS-3-1:0];
647 $display("indirect jump to %o", next_pc);
539 inst_field = inst_field_buffer; 648 inst_field = inst_field_buffer;
540 state = FETCH; 649 state = RETIRE;
541 end 650 end
542 endcase 651 endcase
543 end 652 end
@@ -549,6 +658,7 @@ always_ff @(posedge clk) begin
549 mem_write = 1; 658 mem_write = 1;
550 mem_write_data = address[DATA_BITS-1:0]; 659 mem_write_data = address[DATA_BITS-1:0];
551 led_memdata = mem_write_data; 660 led_memdata = mem_write_data;
661 $display("preinc [%o] <- %o", mem_address, mem_write_data);
552 case (opcode) 662 case (opcode)
553 'o0, 'o1, 'o2: state = `lag(mem_ready) ? AGEN : PREINC; 663 'o0, 'o1, 'o2: state = `lag(mem_ready) ? AGEN : PREINC;
554 'o3, 'o4, 'o5: state = `lag(mem_ready) ? EXEC : PREINC; 664 'o3, 'o4, 'o5: state = `lag(mem_ready) ? EXEC : PREINC;
@@ -576,7 +686,7 @@ always_ff @(posedge clk) begin
576 'o0, 'o1, 'o2: if (! `lag(mem_read_valid)) stall = 1; 686 'o0, 'o1, 'o2: if (! `lag(mem_read_valid)) stall = 1;
577 endcase 687 endcase
578 if (! stall) begin 688 if (! stall) begin
579 state = FETCH; 689 state = RETIRE;
580 case (opcode) 690 case (opcode)
581 'o0: begin led_memdata = `lag(mem_read_data); acc &= `lag(mem_read_data); end 691 'o0: begin led_memdata = `lag(mem_read_data); acc &= `lag(mem_read_data); end
582 'o1: begin led_memdata = `lag(mem_read_data); {link, acc} += {1'b0, `lag(mem_read_data)}; end 692 'o1: begin led_memdata = `lag(mem_read_data); {link, acc} += {1'b0, `lag(mem_read_data)}; end
@@ -586,7 +696,9 @@ always_ff @(posedge clk) begin
586 mem_write = 1; 696 mem_write = 1;
587 mem_write_data = `lag(mem_read_data) + 1; 697 mem_write_data = `lag(mem_read_data) + 1;
588 led_memdata = mem_write_data; 698 led_memdata = mem_write_data;
589 if (mem_write_data == 0) ++pc; 699 $display("store [%o] <- %o", mem_address, mem_write_data);
700 can_skip = 1;
701 if (mem_write_data == 0) skip = 1;
590 state = MEMWAIT; 702 state = MEMWAIT;
591 end 703 end
592 'o3: begin 704 'o3: begin
@@ -595,6 +707,7 @@ always_ff @(posedge clk) begin
595 mem_write = 1; 707 mem_write = 1;
596 mem_write_data = acc; 708 mem_write_data = acc;
597 led_memdata = mem_write_data; 709 led_memdata = mem_write_data;
710 $display("store [%o] <- %o", mem_address, mem_write_data);
598 acc = 0; 711 acc = 0;
599 state = MEMWAIT; 712 state = MEMWAIT;
600 end 713 end
@@ -602,21 +715,22 @@ always_ff @(posedge clk) begin
602 mem_valid = 1; 715 mem_valid = 1;
603 mem_address = address; 716 mem_address = address;
604 mem_write = 1; 717 mem_write = 1;
605 mem_write_data = pc[DATA_BITS-1:0]; 718 mem_write_data = next_pc[DATA_BITS-1:0];
606 led_memdata = mem_write_data; 719 led_memdata = mem_write_data;
607 pc = address[ADDR_BITS-3-1:0] + 1; 720 $display("store [%o] <- %o", mem_address, mem_write_data);
721 next_pc = address[ADDR_BITS-3-1:0] + 1;
608 inst_field = inst_field_buffer; 722 inst_field = inst_field_buffer;
609 state = MEMWAIT; 723 state = MEMWAIT;
610 end 724 end
611 'o5: begin 725 'o5: begin
612 pc = address[ADDR_BITS-3-1:0]; 726 next_pc = address[ADDR_BITS-3-1:0];
613 inst_field = inst_field_buffer; 727 inst_field = inst_field_buffer;
614 end 728 end
615 endcase 729 endcase
616 end 730 end
617 end 731 end
618 732
619 MEMWAIT: state = `lag(mem_ready) ? FETCH : MEMWAIT; 733 MEMWAIT: state = `lag(mem_ready) ? RETIRE : MEMWAIT;
620 734
621 HALT: begin 735 HALT: begin
622 run = 0; 736 run = 0;
@@ -626,14 +740,60 @@ always_ff @(posedge clk) begin
626 740
627 DEPOSIT: begin 741 DEPOSIT: begin
628 if (`lag(mem_ready)) begin 742 if (`lag(mem_ready)) begin
629 state = FETCH; 743 state = FETCH; // Not a retired instruction; go directly to decode
630 page = pc[ADDR_BITS-3-1:7]; 744 page = pc[ADDR_BITS-3-1:7];
631 ++pc; 745 ++pc; // Not a skip; normal part of panel deposit (because we are skipping RETIRE)
632 run = 0; 746 run = 0;
633 end 747 end
634 end 748 end
635 endcase 749 endcase
636 750
751 if (state == RETIRE) begin
752`ifndef SYNTHESIS
753 if (!injected_instruction) begin
754 $display("retiring pc=%o%o", inst_field, pc);
755 $fdisplay(pctrace, "%o%o", inst_field, pc);
756 end
757`endif
758
759 state = FETCH;
760 pc = next_pc;
761
762 if (can_skip) begin
763`ifndef SYNTHESIS
764 if (instcount == nextevent) begin
765 $display("checking instcount=%d force_skip=%d against inferred skip=%d", instcount, force_skip, skip);
766 if (force_skip == 1)
767 skip = 0;
768 else if (force_skip == 2)
769 skip = 1;
770 end
771`endif
772 if (skip) begin
773 $display("skip at instcount=%d pc=%o", instcount, pc);
774 ++pc;
775 end
776 end
777`ifndef SYNTHESIS
778 else if (instcount == nextevent && force_skip != 0) begin
779 $display("Error: forced skip at impossible boundary instcount=%d nextpc=%o", instcount, pc);
780 $finish;
781 end
782`endif
783
784`ifndef SYNTHESIS
785 if (instcount == nextevent) begin
786 nextevent = ~0;
787 if (eventtrace != 0) $fscanf(eventtrace, "%d %d %d", nextevent, force_skip, force_interrupt);
788 $display("nextevent=%d force_skip=%d force_interrupt=%d", nextevent, force_skip, force_interrupt);
789 end
790 if (!injected_instruction) begin
791 ++instcount;
792 if (instcount >= 26000) $finish;
793 end
794`endif
795 end
796
637 if (switch_sing_step) 797 if (switch_sing_step)
638 run = 0; 798 run = 0;
639 799
diff --git a/hdl/jtag_uart.sv b/hdl/jtag_uart.sv
index 096b1c9..ec39c37 100644
--- a/hdl/jtag_uart.sv
+++ b/hdl/jtag_uart.sv
@@ -38,6 +38,9 @@ alt_jtag_atlantic
38 38
39`else 39`else
40 40
41`define DELAY_BITS 16
42bit [`DELAY_BITS-1:0] delay;
43
41bit [7:0] sim_rx_rom [0:(1<<16)-1]; 44bit [7:0] sim_rx_rom [0:(1<<16)-1];
42initial $readmemh("mem/jtag_uart.hex", sim_rx_rom); 45initial $readmemh("mem/jtag_uart.hex", sim_rx_rom);
43 46
@@ -48,6 +51,7 @@ bit [7:0] tx_b_data;
48 51
49always_ff @(posedge clk) begin 52always_ff @(posedge clk) begin
50 if (reset) begin 53 if (reset) begin
54 delay = {(`DELAY_BITS){1'b1}};
51 rx_valid = 0; 55 rx_valid = 0;
52 tx_ready = 0; 56 tx_ready = 0;
53 sim_rx_addr = 0; 57 sim_rx_addr = 0;
@@ -57,13 +61,19 @@ always_ff @(posedge clk) begin
57 61
58 // RX logic 62 // RX logic
59 if (`lag(rx_ready)) rx_valid = 0; 63 if (`lag(rx_ready)) rx_valid = 0;
60 if (!rx_valid && (sim_rx_data != 0)) begin 64 if (delay == 0) begin
65 delay = {(`DELAY_BITS){1'b1}};
66 if (!rx_valid && (sim_rx_data != 8'hff)) begin
61`ifdef JTAG_UART_LOCAL_ECHO 67`ifdef JTAG_UART_LOCAL_ECHO
62 $write("%s", sim_rx_data); 68 $write("%s", sim_rx_data);
69 $fflush();
63`endif 70`endif
64 rx_valid = 1; 71 rx_valid = 1;
65 rx_data = sim_rx_data; 72 rx_data = sim_rx_data;
66 ++sim_rx_addr; 73 ++sim_rx_addr;
74 end
75 end else begin
76 --delay;
67 end 77 end
68 78
69 // TX logic 79 // TX logic
@@ -73,6 +83,7 @@ always_ff @(posedge clk) begin
73 end 83 end
74 if (tx_b_valid) begin 84 if (tx_b_valid) begin
75 $write("%s", tx_b_data); 85 $write("%s", tx_b_data);
86 $fflush();
76 tx_b_valid = 0; 87 tx_b_valid = 0;
77 end 88 end
78 tx_ready = !tx_b_valid; 89 tx_ready = !tx_b_valid;
generated by cgit v1.2.3 (git 2.51.0) at 2026-04-18 19:07:27 -0700