-
Notifications
You must be signed in to change notification settings - Fork 11
/
Copy pathICFP2020_Bluespec_Tutorial_BH.html
5038 lines (5017 loc) · 199 KB
/
ICFP2020_Bluespec_Tutorial_BH.html
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<!--[if IE]><meta http-equiv="X-UA-Compatible" content="IE=edge"><![endif]-->
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta name="generator" content="Asciidoctor 1.5.5">
<meta name="description" content="Bluespec Tutorial">
<meta name="keywords" content="Bluespec, BH, BSV, Bluespec Classic, HLHDL, High-Level Hardware Design, RISC-V">
<meta name="author" content="Rishiyur S. Nikhil, Bluespec, Inc. (c) 2020">
<title>Designing Hardware Systems and Accelerators with Open-Source BH (Bluespec Haskell)</title>
<link rel="stylesheet" href="https://fonts.googleapis.com/css?family=Open+Sans:300,300italic,400,400italic,600,600italic%7CNoto+Serif:400,400italic,700,700italic%7CDroid+Sans+Mono:400,700">
<style>
/* Asciidoctor default stylesheet | MIT License | http://asciidoctor.org */
/* Remove comment around @import statement below when using as a custom stylesheet */
/*@import "https://fonts.googleapis.com/css?family=Open+Sans:300,300italic,400,400italic,600,600italic%7CNoto+Serif:400,400italic,700,700italic%7CDroid+Sans+Mono:400,700";*/
article,aside,details,figcaption,figure,footer,header,hgroup,main,nav,section,summary{display:block}
audio,canvas,video{display:inline-block}
audio:not([controls]){display:none;height:0}
[hidden],template{display:none}
script{display:none!important}
html{font-family:sans-serif;-ms-text-size-adjust:100%;-webkit-text-size-adjust:100%}
a{background:transparent}
a:focus{outline:thin dotted}
a:active,a:hover{outline:0}
h1{font-size:2em;margin:.67em 0}
abbr[title]{border-bottom:1px dotted}
b,strong{font-weight:bold}
dfn{font-style:italic}
hr{-moz-box-sizing:content-box;box-sizing:content-box;height:0}
mark{background:#ff0;color:#000}
code,kbd,pre,samp{font-family:monospace;font-size:1em}
pre{white-space:pre-wrap}
q{quotes:"\201C" "\201D" "\2018" "\2019"}
small{font-size:80%}
sub,sup{font-size:75%;line-height:0;position:relative;vertical-align:baseline}
sup{top:-.5em}
sub{bottom:-.25em}
img{border:0}
svg:not(:root){overflow:hidden}
figure{margin:0}
fieldset{border:1px solid silver;margin:0 2px;padding:.35em .625em .75em}
legend{border:0;padding:0}
button,input,select,textarea{font-family:inherit;font-size:100%;margin:0}
button,input{line-height:normal}
button,select{text-transform:none}
button,html input[type="button"],input[type="reset"],input[type="submit"]{-webkit-appearance:button;cursor:pointer}
button[disabled],html input[disabled]{cursor:default}
input[type="checkbox"],input[type="radio"]{box-sizing:border-box;padding:0}
input[type="search"]{-webkit-appearance:textfield;-moz-box-sizing:content-box;-webkit-box-sizing:content-box;box-sizing:content-box}
input[type="search"]::-webkit-search-cancel-button,input[type="search"]::-webkit-search-decoration{-webkit-appearance:none}
button::-moz-focus-inner,input::-moz-focus-inner{border:0;padding:0}
textarea{overflow:auto;vertical-align:top}
table{border-collapse:collapse;border-spacing:0}
*,*:before,*:after{-moz-box-sizing:border-box;-webkit-box-sizing:border-box;box-sizing:border-box}
html,body{font-size:100%}
body{background:#fff;color:rgba(0,0,0,.8);padding:0;margin:0;font-family:"Noto Serif","DejaVu Serif",serif;font-weight:400;font-style:normal;line-height:1;position:relative;cursor:auto;tab-size:4;-moz-osx-font-smoothing:grayscale;-webkit-font-smoothing:antialiased}
a:hover{cursor:pointer}
img,object,embed{max-width:100%;height:auto}
object,embed{height:100%}
img{-ms-interpolation-mode:bicubic}
.left{float:left!important}
.right{float:right!important}
.text-left{text-align:left!important}
.text-right{text-align:right!important}
.text-center{text-align:center!important}
.text-justify{text-align:justify!important}
.hide{display:none}
img,object,svg{display:inline-block;vertical-align:middle}
textarea{height:auto;min-height:50px}
select{width:100%}
.center{margin-left:auto;margin-right:auto}
.spread{width:100%}
p.lead,.paragraph.lead>p,#preamble>.sectionbody>.paragraph:first-of-type p{font-size:1.21875em;line-height:1.6}
.subheader,.admonitionblock td.content>.title,.audioblock>.title,.exampleblock>.title,.imageblock>.title,.listingblock>.title,.literalblock>.title,.stemblock>.title,.openblock>.title,.paragraph>.title,.quoteblock>.title,table.tableblock>.title,.verseblock>.title,.videoblock>.title,.dlist>.title,.olist>.title,.ulist>.title,.qlist>.title,.hdlist>.title{line-height:1.45;color:#7a2518;font-weight:400;margin-top:0;margin-bottom:.25em}
div,dl,dt,dd,ul,ol,li,h1,h2,h3,#toctitle,.sidebarblock>.content>.title,h4,h5,h6,pre,form,p,blockquote,th,td{margin:0;padding:0;direction:ltr}
a{color:#2156a5;text-decoration:underline;line-height:inherit}
a:hover,a:focus{color:#1d4b8f}
a img{border:none}
p{font-family:inherit;font-weight:400;font-size:1em;line-height:1.6;margin-bottom:1.25em;text-rendering:optimizeLegibility}
p aside{font-size:.875em;line-height:1.35;font-style:italic}
h1,h2,h3,#toctitle,.sidebarblock>.content>.title,h4,h5,h6{font-family:"Open Sans","DejaVu Sans",sans-serif;font-weight:300;font-style:normal;color:#ba3925;text-rendering:optimizeLegibility;margin-top:1em;margin-bottom:.5em;line-height:1.0125em}
h1 small,h2 small,h3 small,#toctitle small,.sidebarblock>.content>.title small,h4 small,h5 small,h6 small{font-size:60%;color:#e99b8f;line-height:0}
h1{font-size:2.125em}
h2{font-size:1.6875em}
h3,#toctitle,.sidebarblock>.content>.title{font-size:1.375em}
h4,h5{font-size:1.125em}
h6{font-size:1em}
hr{border:solid #ddddd8;border-width:1px 0 0;clear:both;margin:1.25em 0 1.1875em;height:0}
em,i{font-style:italic;line-height:inherit}
strong,b{font-weight:bold;line-height:inherit}
small{font-size:60%;line-height:inherit}
code{font-family:"Droid Sans Mono","DejaVu Sans Mono",monospace;font-weight:400;color:rgba(0,0,0,.9)}
ul,ol,dl{font-size:1em;line-height:1.6;margin-bottom:1.25em;list-style-position:outside;font-family:inherit}
ul,ol,ul.no-bullet,ol.no-bullet{margin-left:1.5em}
ul li ul,ul li ol{margin-left:1.25em;margin-bottom:0;font-size:1em}
ul.square li ul,ul.circle li ul,ul.disc li ul{list-style:inherit}
ul.square{list-style-type:square}
ul.circle{list-style-type:circle}
ul.disc{list-style-type:disc}
ul.no-bullet{list-style:none}
ol li ul,ol li ol{margin-left:1.25em;margin-bottom:0}
dl dt{margin-bottom:.3125em;font-weight:bold}
dl dd{margin-bottom:1.25em}
abbr,acronym{text-transform:uppercase;font-size:90%;color:rgba(0,0,0,.8);border-bottom:1px dotted #ddd;cursor:help}
abbr{text-transform:none}
blockquote{margin:0 0 1.25em;padding:.5625em 1.25em 0 1.1875em;border-left:1px solid #ddd}
blockquote cite{display:block;font-size:.9375em;color:rgba(0,0,0,.6)}
blockquote cite:before{content:"\2014 \0020"}
blockquote cite a,blockquote cite a:visited{color:rgba(0,0,0,.6)}
blockquote,blockquote p{line-height:1.6;color:rgba(0,0,0,.85)}
@media only screen and (min-width:768px){h1,h2,h3,#toctitle,.sidebarblock>.content>.title,h4,h5,h6{line-height:1.2}
h1{font-size:2.75em}
h2{font-size:2.3125em}
h3,#toctitle,.sidebarblock>.content>.title{font-size:1.6875em}
h4{font-size:1.4375em}}
table{background:#fff;margin-bottom:1.25em;border:solid 1px #dedede}
table thead,table tfoot{background:#f7f8f7;font-weight:bold}
table thead tr th,table thead tr td,table tfoot tr th,table tfoot tr td{padding:.5em .625em .625em;font-size:inherit;color:rgba(0,0,0,.8);text-align:left}
table tr th,table tr td{padding:.5625em .625em;font-size:inherit;color:rgba(0,0,0,.8)}
table tr.even,table tr.alt,table tr:nth-of-type(even){background:#f8f8f7}
table thead tr th,table tfoot tr th,table tbody tr td,table tr td,table tfoot tr td{display:table-cell;line-height:1.6}
h1,h2,h3,#toctitle,.sidebarblock>.content>.title,h4,h5,h6{line-height:1.2;word-spacing:-.05em}
h1 strong,h2 strong,h3 strong,#toctitle strong,.sidebarblock>.content>.title strong,h4 strong,h5 strong,h6 strong{font-weight:400}
.clearfix:before,.clearfix:after,.float-group:before,.float-group:after{content:" ";display:table}
.clearfix:after,.float-group:after{clear:both}
*:not(pre)>code{font-size:.9375em;font-style:normal!important;letter-spacing:0;padding:.1em .5ex;word-spacing:-.15em;background-color:#f7f7f8;-webkit-border-radius:4px;border-radius:4px;line-height:1.45;text-rendering:optimizeSpeed;word-wrap:break-word}
*:not(pre)>code.nobreak{word-wrap:normal}
*:not(pre)>code.nowrap{white-space:nowrap}
pre,pre>code{line-height:1.45;color:rgba(0,0,0,.9);font-family:"Droid Sans Mono","DejaVu Sans Mono",monospace;font-weight:400;text-rendering:optimizeSpeed}
em em{font-style:normal}
strong strong{font-weight:400}
.keyseq{color:rgba(51,51,51,.8)}
kbd{font-family:"Droid Sans Mono","DejaVu Sans Mono",monospace;display:inline-block;color:rgba(0,0,0,.8);font-size:.65em;line-height:1.45;background-color:#f7f7f7;border:1px solid #ccc;-webkit-border-radius:3px;border-radius:3px;-webkit-box-shadow:0 1px 0 rgba(0,0,0,.2),0 0 0 .1em white inset;box-shadow:0 1px 0 rgba(0,0,0,.2),0 0 0 .1em #fff inset;margin:0 .15em;padding:.2em .5em;vertical-align:middle;position:relative;top:-.1em;white-space:nowrap}
.keyseq kbd:first-child{margin-left:0}
.keyseq kbd:last-child{margin-right:0}
.menuseq,.menu{color:rgba(0,0,0,.8)}
b.button:before,b.button:after{position:relative;top:-1px;font-weight:400}
b.button:before{content:"[";padding:0 3px 0 2px}
b.button:after{content:"]";padding:0 2px 0 3px}
p a>code:hover{color:rgba(0,0,0,.9)}
#header,#content,#footnotes,#footer{width:100%;margin-left:auto;margin-right:auto;margin-top:0;margin-bottom:0;max-width:62.5em;*zoom:1;position:relative;padding-left:.9375em;padding-right:.9375em}
#header:before,#header:after,#content:before,#content:after,#footnotes:before,#footnotes:after,#footer:before,#footer:after{content:" ";display:table}
#header:after,#content:after,#footnotes:after,#footer:after{clear:both}
#content{margin-top:1.25em}
#content:before{content:none}
#header>h1:first-child{color:rgba(0,0,0,.85);margin-top:2.25rem;margin-bottom:0}
#header>h1:first-child+#toc{margin-top:8px;border-top:1px solid #ddddd8}
#header>h1:only-child,body.toc2 #header>h1:nth-last-child(2){border-bottom:1px solid #ddddd8;padding-bottom:8px}
#header .details{border-bottom:1px solid #ddddd8;line-height:1.45;padding-top:.25em;padding-bottom:.25em;padding-left:.25em;color:rgba(0,0,0,.6);display:-ms-flexbox;display:-webkit-flex;display:flex;-ms-flex-flow:row wrap;-webkit-flex-flow:row wrap;flex-flow:row wrap}
#header .details span:first-child{margin-left:-.125em}
#header .details span.email a{color:rgba(0,0,0,.85)}
#header .details br{display:none}
#header .details br+span:before{content:"\00a0\2013\00a0"}
#header .details br+span.author:before{content:"\00a0\22c5\00a0";color:rgba(0,0,0,.85)}
#header .details br+span#revremark:before{content:"\00a0|\00a0"}
#header #revnumber{text-transform:capitalize}
#header #revnumber:after{content:"\00a0"}
#content>h1:first-child:not([class]){color:rgba(0,0,0,.85);border-bottom:1px solid #ddddd8;padding-bottom:8px;margin-top:0;padding-top:1rem;margin-bottom:1.25rem}
#toc{border-bottom:1px solid #efefed;padding-bottom:.5em}
#toc>ul{margin-left:.125em}
#toc ul.sectlevel0>li>a{font-style:italic}
#toc ul.sectlevel0 ul.sectlevel1{margin:.5em 0}
#toc ul{font-family:"Open Sans","DejaVu Sans",sans-serif;list-style-type:none}
#toc li{line-height:1.3334;margin-top:.3334em}
#toc a{text-decoration:none}
#toc a:active{text-decoration:underline}
#toctitle{color:#7a2518;font-size:1.2em}
@media only screen and (min-width:768px){#toctitle{font-size:1.375em}
body.toc2{padding-left:15em;padding-right:0}
#toc.toc2{margin-top:0!important;background-color:#f8f8f7;position:fixed;width:15em;left:0;top:0;border-right:1px solid #efefed;border-top-width:0!important;border-bottom-width:0!important;z-index:1000;padding:1.25em 1em;height:100%;overflow:auto}
#toc.toc2 #toctitle{margin-top:0;margin-bottom:.8rem;font-size:1.2em}
#toc.toc2>ul{font-size:.9em;margin-bottom:0}
#toc.toc2 ul ul{margin-left:0;padding-left:1em}
#toc.toc2 ul.sectlevel0 ul.sectlevel1{padding-left:0;margin-top:.5em;margin-bottom:.5em}
body.toc2.toc-right{padding-left:0;padding-right:15em}
body.toc2.toc-right #toc.toc2{border-right-width:0;border-left:1px solid #efefed;left:auto;right:0}}
@media only screen and (min-width:1280px){body.toc2{padding-left:20em;padding-right:0}
#toc.toc2{width:20em}
#toc.toc2 #toctitle{font-size:1.375em}
#toc.toc2>ul{font-size:.95em}
#toc.toc2 ul ul{padding-left:1.25em}
body.toc2.toc-right{padding-left:0;padding-right:20em}}
#content #toc{border-style:solid;border-width:1px;border-color:#e0e0dc;margin-bottom:1.25em;padding:1.25em;background:#f8f8f7;-webkit-border-radius:4px;border-radius:4px}
#content #toc>:first-child{margin-top:0}
#content #toc>:last-child{margin-bottom:0}
#footer{max-width:100%;background-color:rgba(0,0,0,.8);padding:1.25em}
#footer-text{color:rgba(255,255,255,.8);line-height:1.44}
.sect1{padding-bottom:.625em}
@media only screen and (min-width:768px){.sect1{padding-bottom:1.25em}}
.sect1+.sect1{border-top:1px solid #efefed}
#content h1>a.anchor,h2>a.anchor,h3>a.anchor,#toctitle>a.anchor,.sidebarblock>.content>.title>a.anchor,h4>a.anchor,h5>a.anchor,h6>a.anchor{position:absolute;z-index:1001;width:1.5ex;margin-left:-1.5ex;display:block;text-decoration:none!important;visibility:hidden;text-align:center;font-weight:400}
#content h1>a.anchor:before,h2>a.anchor:before,h3>a.anchor:before,#toctitle>a.anchor:before,.sidebarblock>.content>.title>a.anchor:before,h4>a.anchor:before,h5>a.anchor:before,h6>a.anchor:before{content:"\00A7";font-size:.85em;display:block;padding-top:.1em}
#content h1:hover>a.anchor,#content h1>a.anchor:hover,h2:hover>a.anchor,h2>a.anchor:hover,h3:hover>a.anchor,#toctitle:hover>a.anchor,.sidebarblock>.content>.title:hover>a.anchor,h3>a.anchor:hover,#toctitle>a.anchor:hover,.sidebarblock>.content>.title>a.anchor:hover,h4:hover>a.anchor,h4>a.anchor:hover,h5:hover>a.anchor,h5>a.anchor:hover,h6:hover>a.anchor,h6>a.anchor:hover{visibility:visible}
#content h1>a.link,h2>a.link,h3>a.link,#toctitle>a.link,.sidebarblock>.content>.title>a.link,h4>a.link,h5>a.link,h6>a.link{color:#ba3925;text-decoration:none}
#content h1>a.link:hover,h2>a.link:hover,h3>a.link:hover,#toctitle>a.link:hover,.sidebarblock>.content>.title>a.link:hover,h4>a.link:hover,h5>a.link:hover,h6>a.link:hover{color:#a53221}
.audioblock,.imageblock,.literalblock,.listingblock,.stemblock,.videoblock{margin-bottom:1.25em}
.admonitionblock td.content>.title,.audioblock>.title,.exampleblock>.title,.imageblock>.title,.listingblock>.title,.literalblock>.title,.stemblock>.title,.openblock>.title,.paragraph>.title,.quoteblock>.title,table.tableblock>.title,.verseblock>.title,.videoblock>.title,.dlist>.title,.olist>.title,.ulist>.title,.qlist>.title,.hdlist>.title{text-rendering:optimizeLegibility;text-align:left;font-family:"Noto Serif","DejaVu Serif",serif;font-size:1rem;font-style:italic}
table.tableblock>caption.title{white-space:nowrap;overflow:visible;max-width:0}
.paragraph.lead>p,#preamble>.sectionbody>.paragraph:first-of-type p{color:rgba(0,0,0,.85)}
table.tableblock #preamble>.sectionbody>.paragraph:first-of-type p{font-size:inherit}
.admonitionblock>table{border-collapse:separate;border:0;background:none;width:100%}
.admonitionblock>table td.icon{text-align:center;width:80px}
.admonitionblock>table td.icon img{max-width:none}
.admonitionblock>table td.icon .title{font-weight:bold;font-family:"Open Sans","DejaVu Sans",sans-serif;text-transform:uppercase}
.admonitionblock>table td.content{padding-left:1.125em;padding-right:1.25em;border-left:1px solid #ddddd8;color:rgba(0,0,0,.6)}
.admonitionblock>table td.content>:last-child>:last-child{margin-bottom:0}
.exampleblock>.content{border-style:solid;border-width:1px;border-color:#e6e6e6;margin-bottom:1.25em;padding:1.25em;background:#fff;-webkit-border-radius:4px;border-radius:4px}
.exampleblock>.content>:first-child{margin-top:0}
.exampleblock>.content>:last-child{margin-bottom:0}
.sidebarblock{border-style:solid;border-width:1px;border-color:#e0e0dc;margin-bottom:1.25em;padding:1.25em;background:#f8f8f7;-webkit-border-radius:4px;border-radius:4px}
.sidebarblock>:first-child{margin-top:0}
.sidebarblock>:last-child{margin-bottom:0}
.sidebarblock>.content>.title{color:#7a2518;margin-top:0;text-align:center}
.exampleblock>.content>:last-child>:last-child,.exampleblock>.content .olist>ol>li:last-child>:last-child,.exampleblock>.content .ulist>ul>li:last-child>:last-child,.exampleblock>.content .qlist>ol>li:last-child>:last-child,.sidebarblock>.content>:last-child>:last-child,.sidebarblock>.content .olist>ol>li:last-child>:last-child,.sidebarblock>.content .ulist>ul>li:last-child>:last-child,.sidebarblock>.content .qlist>ol>li:last-child>:last-child{margin-bottom:0}
.literalblock pre,.listingblock pre:not(.highlight),.listingblock pre[class="highlight"],.listingblock pre[class^="highlight "],.listingblock pre.CodeRay,.listingblock pre.prettyprint{background:#f7f7f8}
.sidebarblock .literalblock pre,.sidebarblock .listingblock pre:not(.highlight),.sidebarblock .listingblock pre[class="highlight"],.sidebarblock .listingblock pre[class^="highlight "],.sidebarblock .listingblock pre.CodeRay,.sidebarblock .listingblock pre.prettyprint{background:#f2f1f1}
.literalblock pre,.literalblock pre[class],.listingblock pre,.listingblock pre[class]{-webkit-border-radius:4px;border-radius:4px;word-wrap:break-word;padding:1em;font-size:.8125em}
.literalblock pre.nowrap,.literalblock pre[class].nowrap,.listingblock pre.nowrap,.listingblock pre[class].nowrap{overflow-x:auto;white-space:pre;word-wrap:normal}
@media only screen and (min-width:768px){.literalblock pre,.literalblock pre[class],.listingblock pre,.listingblock pre[class]{font-size:.90625em}}
@media only screen and (min-width:1280px){.literalblock pre,.literalblock pre[class],.listingblock pre,.listingblock pre[class]{font-size:1em}}
.literalblock.output pre{color:#f7f7f8;background-color:rgba(0,0,0,.9)}
.listingblock pre.highlightjs{padding:0}
.listingblock pre.highlightjs>code{padding:1em;-webkit-border-radius:4px;border-radius:4px}
.listingblock pre.prettyprint{border-width:0}
.listingblock>.content{position:relative}
.listingblock code[data-lang]:before{display:none;content:attr(data-lang);position:absolute;font-size:.75em;top:.425rem;right:.5rem;line-height:1;text-transform:uppercase;color:#999}
.listingblock:hover code[data-lang]:before{display:block}
.listingblock.terminal pre .command:before{content:attr(data-prompt);padding-right:.5em;color:#999}
.listingblock.terminal pre .command:not([data-prompt]):before{content:"$"}
table.pyhltable{border-collapse:separate;border:0;margin-bottom:0;background:none}
table.pyhltable td{vertical-align:top;padding-top:0;padding-bottom:0;line-height:1.45}
table.pyhltable td.code{padding-left:.75em;padding-right:0}
pre.pygments .lineno,table.pyhltable td:not(.code){color:#999;padding-left:0;padding-right:.5em;border-right:1px solid #ddddd8}
pre.pygments .lineno{display:inline-block;margin-right:.25em}
table.pyhltable .linenodiv{background:none!important;padding-right:0!important}
.quoteblock{margin:0 1em 1.25em 1.5em;display:table}
.quoteblock>.title{margin-left:-1.5em;margin-bottom:.75em}
.quoteblock blockquote,.quoteblock blockquote p{color:rgba(0,0,0,.85);font-size:1.15rem;line-height:1.75;word-spacing:.1em;letter-spacing:0;font-style:italic;text-align:justify}
.quoteblock blockquote{margin:0;padding:0;border:0}
.quoteblock blockquote:before{content:"\201c";float:left;font-size:2.75em;font-weight:bold;line-height:.6em;margin-left:-.6em;color:#7a2518;text-shadow:0 1px 2px rgba(0,0,0,.1)}
.quoteblock blockquote>.paragraph:last-child p{margin-bottom:0}
.quoteblock .attribution{margin-top:.5em;margin-right:.5ex;text-align:right}
.quoteblock .quoteblock{margin-left:0;margin-right:0;padding:.5em 0;border-left:3px solid rgba(0,0,0,.6)}
.quoteblock .quoteblock blockquote{padding:0 0 0 .75em}
.quoteblock .quoteblock blockquote:before{display:none}
.verseblock{margin:0 1em 1.25em 1em}
.verseblock pre{font-family:"Open Sans","DejaVu Sans",sans;font-size:1.15rem;color:rgba(0,0,0,.85);font-weight:300;text-rendering:optimizeLegibility}
.verseblock pre strong{font-weight:400}
.verseblock .attribution{margin-top:1.25rem;margin-left:.5ex}
.quoteblock .attribution,.verseblock .attribution{font-size:.9375em;line-height:1.45;font-style:italic}
.quoteblock .attribution br,.verseblock .attribution br{display:none}
.quoteblock .attribution cite,.verseblock .attribution cite{display:block;letter-spacing:-.025em;color:rgba(0,0,0,.6)}
.quoteblock.abstract{margin:0 0 1.25em 0;display:block}
.quoteblock.abstract blockquote,.quoteblock.abstract blockquote p{text-align:left;word-spacing:0}
.quoteblock.abstract blockquote:before,.quoteblock.abstract blockquote p:first-of-type:before{display:none}
table.tableblock{max-width:100%;border-collapse:separate}
table.tableblock td>.paragraph:last-child p>p:last-child,table.tableblock th>p:last-child,table.tableblock td>p:last-child{margin-bottom:0}
table.tableblock,th.tableblock,td.tableblock{border:0 solid #dedede}
table.grid-all th.tableblock,table.grid-all td.tableblock{border-width:0 1px 1px 0}
table.grid-all tfoot>tr>th.tableblock,table.grid-all tfoot>tr>td.tableblock{border-width:1px 1px 0 0}
table.grid-cols th.tableblock,table.grid-cols td.tableblock{border-width:0 1px 0 0}
table.grid-all *>tr>.tableblock:last-child,table.grid-cols *>tr>.tableblock:last-child{border-right-width:0}
table.grid-rows th.tableblock,table.grid-rows td.tableblock{border-width:0 0 1px 0}
table.grid-all tbody>tr:last-child>th.tableblock,table.grid-all tbody>tr:last-child>td.tableblock,table.grid-all thead:last-child>tr>th.tableblock,table.grid-rows tbody>tr:last-child>th.tableblock,table.grid-rows tbody>tr:last-child>td.tableblock,table.grid-rows thead:last-child>tr>th.tableblock{border-bottom-width:0}
table.grid-rows tfoot>tr>th.tableblock,table.grid-rows tfoot>tr>td.tableblock{border-width:1px 0 0 0}
table.frame-all{border-width:1px}
table.frame-sides{border-width:0 1px}
table.frame-topbot{border-width:1px 0}
th.halign-left,td.halign-left{text-align:left}
th.halign-right,td.halign-right{text-align:right}
th.halign-center,td.halign-center{text-align:center}
th.valign-top,td.valign-top{vertical-align:top}
th.valign-bottom,td.valign-bottom{vertical-align:bottom}
th.valign-middle,td.valign-middle{vertical-align:middle}
table thead th,table tfoot th{font-weight:bold}
tbody tr th{display:table-cell;line-height:1.6;background:#f7f8f7}
tbody tr th,tbody tr th p,tfoot tr th,tfoot tr th p{color:rgba(0,0,0,.8);font-weight:bold}
p.tableblock>code:only-child{background:none;padding:0}
p.tableblock{font-size:1em}
td>div.verse{white-space:pre}
ol{margin-left:1.75em}
ul li ol{margin-left:1.5em}
dl dd{margin-left:1.125em}
dl dd:last-child,dl dd:last-child>:last-child{margin-bottom:0}
ol>li p,ul>li p,ul dd,ol dd,.olist .olist,.ulist .ulist,.ulist .olist,.olist .ulist{margin-bottom:.625em}
ul.unstyled,ol.unnumbered,ul.checklist,ul.none{list-style-type:none}
ul.unstyled,ol.unnumbered,ul.checklist{margin-left:.625em}
ul.checklist li>p:first-child>.fa-square-o:first-child,ul.checklist li>p:first-child>.fa-check-square-o:first-child{width:1em;font-size:.85em}
ul.checklist li>p:first-child>input[type="checkbox"]:first-child{width:1em;position:relative;top:1px}
ul.inline{margin:0 auto .625em auto;margin-left:-1.375em;margin-right:0;padding:0;list-style:none;overflow:hidden}
ul.inline>li{list-style:none;float:left;margin-left:1.375em;display:block}
ul.inline>li>*{display:block}
.unstyled dl dt{font-weight:400;font-style:normal}
ol.arabic{list-style-type:decimal}
ol.decimal{list-style-type:decimal-leading-zero}
ol.loweralpha{list-style-type:lower-alpha}
ol.upperalpha{list-style-type:upper-alpha}
ol.lowerroman{list-style-type:lower-roman}
ol.upperroman{list-style-type:upper-roman}
ol.lowergreek{list-style-type:lower-greek}
.hdlist>table,.colist>table{border:0;background:none}
.hdlist>table>tbody>tr,.colist>table>tbody>tr{background:none}
td.hdlist1,td.hdlist2{vertical-align:top;padding:0 .625em}
td.hdlist1{font-weight:bold;padding-bottom:1.25em}
.literalblock+.colist,.listingblock+.colist{margin-top:-.5em}
.colist>table tr>td:first-of-type{padding:0 .75em;line-height:1}
.colist>table tr>td:last-of-type{padding:.25em 0}
.thumb,.th{line-height:0;display:inline-block;border:solid 4px #fff;-webkit-box-shadow:0 0 0 1px #ddd;box-shadow:0 0 0 1px #ddd}
.imageblock.left,.imageblock[style*="float: left"]{margin:.25em .625em 1.25em 0}
.imageblock.right,.imageblock[style*="float: right"]{margin:.25em 0 1.25em .625em}
.imageblock>.title{margin-bottom:0}
.imageblock.thumb,.imageblock.th{border-width:6px}
.imageblock.thumb>.title,.imageblock.th>.title{padding:0 .125em}
.image.left,.image.right{margin-top:.25em;margin-bottom:.25em;display:inline-block;line-height:0}
.image.left{margin-right:.625em}
.image.right{margin-left:.625em}
a.image{text-decoration:none;display:inline-block}
a.image object{pointer-events:none}
sup.footnote,sup.footnoteref{font-size:.875em;position:static;vertical-align:super}
sup.footnote a,sup.footnoteref a{text-decoration:none}
sup.footnote a:active,sup.footnoteref a:active{text-decoration:underline}
#footnotes{padding-top:.75em;padding-bottom:.75em;margin-bottom:.625em}
#footnotes hr{width:20%;min-width:6.25em;margin:-.25em 0 .75em 0;border-width:1px 0 0 0}
#footnotes .footnote{padding:0 .375em 0 .225em;line-height:1.3334;font-size:.875em;margin-left:1.2em;text-indent:-1.05em;margin-bottom:.2em}
#footnotes .footnote a:first-of-type{font-weight:bold;text-decoration:none}
#footnotes .footnote:last-of-type{margin-bottom:0}
#content #footnotes{margin-top:-.625em;margin-bottom:0;padding:.75em 0}
.gist .file-data>table{border:0;background:#fff;width:100%;margin-bottom:0}
.gist .file-data>table td.line-data{width:99%}
div.unbreakable{page-break-inside:avoid}
.big{font-size:larger}
.small{font-size:smaller}
.underline{text-decoration:underline}
.overline{text-decoration:overline}
.line-through{text-decoration:line-through}
.aqua{color:#00bfbf}
.aqua-background{background-color:#00fafa}
.black{color:#000}
.black-background{background-color:#000}
.blue{color:#0000bf}
.blue-background{background-color:#0000fa}
.fuchsia{color:#bf00bf}
.fuchsia-background{background-color:#fa00fa}
.gray{color:#606060}
.gray-background{background-color:#7d7d7d}
.green{color:#006000}
.green-background{background-color:#007d00}
.lime{color:#00bf00}
.lime-background{background-color:#00fa00}
.maroon{color:#600000}
.maroon-background{background-color:#7d0000}
.navy{color:#000060}
.navy-background{background-color:#00007d}
.olive{color:#606000}
.olive-background{background-color:#7d7d00}
.purple{color:#600060}
.purple-background{background-color:#7d007d}
.red{color:#bf0000}
.red-background{background-color:#fa0000}
.silver{color:#909090}
.silver-background{background-color:#bcbcbc}
.teal{color:#006060}
.teal-background{background-color:#007d7d}
.white{color:#bfbfbf}
.white-background{background-color:#fafafa}
.yellow{color:#bfbf00}
.yellow-background{background-color:#fafa00}
span.icon>.fa{cursor:default}
.admonitionblock td.icon [class^="fa icon-"]{font-size:2.5em;text-shadow:1px 1px 2px rgba(0,0,0,.5);cursor:default}
.admonitionblock td.icon .icon-note:before{content:"\f05a";color:#19407c}
.admonitionblock td.icon .icon-tip:before{content:"\f0eb";text-shadow:1px 1px 2px rgba(155,155,0,.8);color:#111}
.admonitionblock td.icon .icon-warning:before{content:"\f071";color:#bf6900}
.admonitionblock td.icon .icon-caution:before{content:"\f06d";color:#bf3400}
.admonitionblock td.icon .icon-important:before{content:"\f06a";color:#bf0000}
.conum[data-value]{display:inline-block;color:#fff!important;background-color:rgba(0,0,0,.8);-webkit-border-radius:100px;border-radius:100px;text-align:center;font-size:.75em;width:1.67em;height:1.67em;line-height:1.67em;font-family:"Open Sans","DejaVu Sans",sans-serif;font-style:normal;font-weight:bold}
.conum[data-value] *{color:#fff!important}
.conum[data-value]+b{display:none}
.conum[data-value]:after{content:attr(data-value)}
pre .conum[data-value]{position:relative;top:-.125em}
b.conum *{color:inherit!important}
.conum:not([data-value]):empty{display:none}
dt,th.tableblock,td.content,div.footnote{text-rendering:optimizeLegibility}
h1,h2,p,td.content,span.alt{letter-spacing:-.01em}
p strong,td.content strong,div.footnote strong{letter-spacing:-.005em}
p,blockquote,dt,td.content,span.alt{font-size:1.0625rem}
p{margin-bottom:1.25rem}
.sidebarblock p,.sidebarblock dt,.sidebarblock td.content,p.tableblock{font-size:1em}
.exampleblock>.content{background-color:#fffef7;border-color:#e0e0dc;-webkit-box-shadow:0 1px 4px #e0e0dc;box-shadow:0 1px 4px #e0e0dc}
.print-only{display:none!important}
@media print{@page{margin:1.25cm .75cm}
*{-webkit-box-shadow:none!important;box-shadow:none!important;text-shadow:none!important}
a{color:inherit!important;text-decoration:underline!important}
a.bare,a[href^="#"],a[href^="mailto:"]{text-decoration:none!important}
a[href^="http:"]:not(.bare):after,a[href^="https:"]:not(.bare):after{content:"(" attr(href) ")";display:inline-block;font-size:.875em;padding-left:.25em}
abbr[title]:after{content:" (" attr(title) ")"}
pre,blockquote,tr,img,object,svg{page-break-inside:avoid}
thead{display:table-header-group}
svg{max-width:100%}
p,blockquote,dt,td.content{font-size:1em;orphans:3;widows:3}
h2,h3,#toctitle,.sidebarblock>.content>.title{page-break-after:avoid}
#toc,.sidebarblock,.exampleblock>.content{background:none!important}
#toc{border-bottom:1px solid #ddddd8!important;padding-bottom:0!important}
.sect1{padding-bottom:0!important}
.sect1+.sect1{border:0!important}
#header>h1:first-child{margin-top:1.25rem}
body.book #header{text-align:center}
body.book #header>h1:first-child{border:0!important;margin:2.5em 0 1em 0}
body.book #header .details{border:0!important;display:block;padding:0!important}
body.book #header .details span:first-child{margin-left:0!important}
body.book #header .details br{display:block}
body.book #header .details br+span:before{content:none!important}
body.book #toc{border:0!important;text-align:left!important;padding:0!important;margin:0!important}
body.book #toc,body.book #preamble,body.book h1.sect0,body.book .sect1>h2{page-break-before:always}
.listingblock code[data-lang]:before{display:block}
#footer{background:none!important;padding:0 .9375em}
#footer-text{color:rgba(0,0,0,.6)!important;font-size:.9em}
.hide-on-print{display:none!important}
.print-only{display:block!important}
.hide-for-print{display:none!important}
.show-for-print{display:inherit!important}}
</style>
</head>
<body class="article toc2 toc-left">
<div id="header">
<h1>Designing Hardware Systems and Accelerators with Open-Source BH (Bluespec Haskell)</h1>
<div class="details">
<span id="author" class="author">Rishiyur S. Nikhil, Bluespec, Inc. (c) 2020</span><br>
<span id="revnumber">version v0.1,</span>
<span id="revdate">2020-08-10</span>
<br><span id="revremark">First draft</span>
</div>
<div id="toc" class="toc2">
<div id="toctitle">Contents</div>
<ul class="sectlevel1">
<li><a href="#_abstract">1. ABSTRACT</a></li>
<li><a href="#_please_install_the_following">2. Please install the following.</a></li>
<li><a href="#_introduction">3. Introduction</a>
<ul class="sectlevel2">
<li><a href="#_why_should_one_design_and_create_hardware">3.1. Why Should One Design and Create Hardware?</a></li>
<li><a href="#_why_em_shouldn_t_em_one_design_and_create_hardware">3.2. Why <em>Shouldn’t</em> One Design and Create Hardware?</a></li>
<li><a href="#_the_flows_processes_for_developing_hardware">3.3. The flows/processes for developing hardware</a></li>
<li><a href="#_what_is_an_fpga">3.4. What is an FPGA?</a></li>
<li><a href="#_how_where_can_i_get_an_fpga_and_fpga_asic_tools">3.5. How/Where can I get an FPGA and FPGA/ASIC tools?</a></li>
<li><a href="#_plan_for_this_tutorial">3.6. Plan for this tutorial</a></li>
<li><a href="#_a_note_on_the_em_bsc_em_tool_and_bluespec_bh_and_bsv_code_syntax">3.7. A note on the <em>bsc</em> tool and Bluespec BH and BSV code syntax</a></li>
</ul>
</li>
<li><a href="#_limbering_up_hello_world">4. Limbering up: “Hello World!”</a>
<ul class="sectlevel2">
<li><a href="#_the_code">4.1. The code</a>
<ul class="sectlevel3">
<li><a href="#_structure_executing_a_bh_bsv_program_describes_a_piece_of_hardware">4.1.1. STRUCTURE: executing a BH/BSV program describes a piece of hardware</a></li>
<li><a href="#_behavior_executing_the_hardware">4.1.2. BEHAVIOR: executing the hardware</a></li>
<li><a href="#_let_s_do_it_bluesim_compile_link_and_simulate">4.1.3. Let’s do it! Bluesim compile, link and simulate</a></li>
<li><a href="#_a_fanciful_visualization_of_verilog_hardware_described_by_the_code">4.1.4. A (fanciful) visualization of Verilog hardware described by the code</a></li>
<li><a href="#_let_s_do_it_verilog_compile_link_and_simulate">4.1.5. Let’s do it! Verilog compile, link and simulate</a></li>
</ul>
</li>
<li><a href="#_stepping_back_for_some_perspective_haskell_or_pls_in_general_vs_bh_bsv">4.2. Stepping back for some perspective: Haskell (or PLs in general) vs. BH/BSV</a></li>
<li><a href="#_hello_world_version_b_packages_and_modules">4.3. Hello World! Version (b): Packages and Modules</a>
<ul class="sectlevel3">
<li><a href="#_interfaces_and_interface_types">4.3.1. Interfaces and interface types</a></li>
<li><a href="#_synthesis_boundaries">4.3.2. Synthesis boundaries</a></li>
<li><a href="#_packages_imports_and_files">4.3.3. Packages, imports, and files</a></li>
<li><a href="#_separate_compilation">4.3.4. Separate compilation</a></li>
<li><a href="#_instantiating_modules_and_invoking_their_methods">4.3.5. Instantiating modules and invoking their methods</a></li>
<li><a href="#_let_s_do_it_compile_link_and_simulate_the_example">4.3.6. Let’s do it! Compile, link and simulate the example:</a></li>
</ul>
</li>
<li><a href="#_hello_world_version_c_state_and_time">4.4. Hello World! Version (c): State and Time</a>
<ul class="sectlevel3">
<li><a href="#_action_actionvalue_and_value_interface_methods">4.4.1. Action, ActionValue and Value interface methods</a></li>
<li><a href="#_algebraic_types">4.4.2. Algebraic types</a></li>
<li><a href="#_registers_instantiation_initializing_and_operations">4.4.3. Registers: Instantiation, initializing, and operations</a></li>
<li><a href="#_local_values_bit_selection_and_combinational_circuits">4.4.4. Local values, bit selection and combinational circuits</a></li>
<li><a href="#_interface_method_conditions_and_actions">4.4.5. Interface method conditions and actions</a></li>
<li><a href="#_rule_conditions">4.4.6. Rule conditions</a></li>
<li><a href="#_let_s_do_it_compile_link_and_simulate_the_example_2">4.4.7. Let’s do it! Compile, link and simulate the example:</a></li>
<li><a href="#_visualizing_the_hardware_for_code_mktop_code_rule_level_view">4.4.8. Visualizing the hardware for <code>mkTop</code>: rule-level view</a></li>
<li><a href="#_visualizing_the_hardware_for_code_mktop_code_verilog_rtl_view">4.4.9. Visualizing the hardware for <code>mkTop</code>: Verilog RTL view</a></li>
<li><a href="#_visualizing_the_hardware_for_code_mkdeepthought_code_rule_level_view">4.4.10. Visualizing the hardware for <code>mkDeepThought</code>: rule-level view</a></li>
<li><a href="#_visualizing_the_hardware_for_code_mkdeepthought_code_verilog_rtl_view">4.4.11. Visualizing the hardware for <code>mkDeepThought</code>: Verilog RTL view</a></li>
<li><a href="#_waveforms_vcd_files_and_waveform_viewers">4.4.12. Waveforms: VCD files and Waveform viewers</a></li>
</ul>
</li>
<li><a href="#_simulation_and_synthesis_semantics_are_the_same_in_bh_bsv">4.5. Simulation and Synthesis semantics are the same in BH/BSV</a></li>
<li><a href="#HDLS_vs_HLS">4.6. HLHDLs vs. HLS: precise specification of micro-architecture</a></li>
<li><a href="#_numeric_types_and_kinds_in_bh_bsv">4.7. Numeric types and kinds in BH/BSV</a></li>
</ul>
</li>
<li><a href="#_introducing_concurrency_with_bubblesort_as_example">5. Introducing Concurrency with Bubblesort as Example</a>
<ul class="sectlevel2">
<li><a href="#_bubblesort_version_a_sequential_a_finite_state_machine">5.1. Bubblesort Version (a): Sequential (a finite state machine)</a>
<ul class="sectlevel3">
<li><a href="#__code_mkbubblesort_code_interface">5.1.1. <code>mkBubblesort</code>: interface</a></li>
<li><a href="#__code_mkbubblesort_code_state_elements">5.1.2. <code>mkBubblesort</code>: state elements</a></li>
<li><a href="#__code_mkbubblesort_code_input">5.1.3. <code>mkBubblesort</code>: input</a></li>
<li><a href="#__code_mkbubblesort_code_sorting">5.1.4. <code>mkBubblesort</code>: sorting</a></li>
<li><a href="#__code_mkbubblesort_code_termination">5.1.5. <code>mkBubblesort</code>: termination</a></li>
<li><a href="#__code_mkbubblesort_code_output">5.1.6. <code>mkBubblesort</code>: output</a></li>
<li><a href="#__code_mktop_code_the_driver_testbench_in_file_code_top_bs_code">5.1.7. <code>mkTop</code>, the driver “testbench” (in file <code>Top.bs</code>)</a></li>
<li><a href="#_let_s_do_it_compile_link_and_simulate_the_example_3">5.1.8. Let’s do it! Compile, link and simulate the example</a></li>
<li><a href="#_waveforms_code_gtkwave_dump_vcd_code">5.1.9. Waveforms (<code>$ gtkwave dump.vcd</code>)</a></li>
</ul>
</li>
<li><a href="#_bubblesort_version_b_with_concurrency">5.2. Bubblesort Version (b): with concurrency</a>
<ul class="sectlevel3">
<li><a href="#_bubblesort_with_concurrency">5.2.1. Bubblesort with concurrency</a></li>
<li><a href="#_swapping">5.2.2. Swapping</a></li>
<li><a href="#_swapping_and_concurrency">5.2.3. Swapping and concurrency</a></li>
<li><a href="#_input">5.2.4. Input</a></li>
<li><a href="#_output">5.2.5. Output</a></li>
<li><a href="#_let_s_do_it_compile_link_and_simulate_the_example_and_look_at_waves">5.2.6. Let’s do it! Compile, link and simulate the example, and look at waves</a></li>
</ul>
</li>
<li><a href="#_bubblesort_versions_c_d_and_e_generalizations">5.3. Bubblesort Versions (c), (d) and (e): generalizations</a>
<ul class="sectlevel3">
<li><a href="#_bubblesort_version_e_highlights">5.3.1. Bubblesort Version (e): highlights</a></li>
</ul>
</li>
<li><a href="#_an_aside_on_style">5.4. An Aside on Style</a></li>
</ul>
</li>
<li><a href="#_pipelining_memory_access_and_accelerators_example_mergesort">6. Pipelining, memory access and accelerators (example: “Mergesort”)</a>
<ul class="sectlevel2">
<li><a href="#_where_do_accelerators_fit_into_a_computer_system">6.1. Where do Accelerators Fit into a Computer System?</a></li>
<li><a href="#_our_example_a_memory_to_memory_mergesort_accelerator">6.2. Our example: a memory-to-memory “mergesort” accelerator</a></li>
<li><a href="#_mergesort_source_codes">6.3. Mergesort: source codes</a></li>
<li><a href="#_mergesort_algorithm">6.4. Mergesort algorithm</a></li>
<li><a href="#_mergesort_visualizing_the_merge_step">6.5. Mergesort: visualizing the merge step</a></li>
<li><a href="#_the_merge_engine_sorts_two_input_segments_into_1_output_segment">6.6. The Merge Engine (sorts two input segments into 1 output segment)</a></li>
<li><a href="#_the_merge_engine_interface">6.7. The Merge Engine: interface</a></li>
<li><a href="#_the_merge_engine_talking_to_the_axi4_interconnect_bus">6.8. The Merge Engine: Talking to the AXI4 interconnect (bus)</a></li>
<li><a href="#_the_merge_engine_flow">6.9. The Merge Engine: Flow</a></li>
<li><a href="#_the_merge_engine_avoiding_deadlock_in_the_pipeline">6.10. The Merge Engine: Avoiding Deadlock in the Pipeline</a></li>
<li><a href="#_the_mergesort_module_code_mkaxi4_accel_code_in_file_code_axi4_accel_bs_code">6.11. The Mergesort Module (<code>mkAXI4_Accel</code> in file <code>AXI4_Accel.bs</code>)</a></li>
<li><a href="#_the_mergesort_module_code_code_mkaxi4_accel_code_in_file_code_axi4_accel_bs_code">6.12. The Mergesort Module Code (<code>mkAXI4_Accel</code> in file <code>AXI4_Accel.bs</code>)</a></li>
<li><a href="#_let_s_do_it_compile_link_the_example_but_don_t_try_simulating_yet">6.13. Let’s do it! Compile, link the example (but don’t try simulating yet)</a></li>
<li><a href="#_for_simulation_risc_v_machine_code_for_flute_execution">6.14. For simulation: RISC-V machine-code for Flute execution</a></li>
<li><a href="#_let_s_do_it_run_the_hello_world_risc_v_binary">6.15. Let’s do it! Run the “Hello, World!” RISC-V binary.</a></li>
<li><a href="#_c_code_to_test_the_mergesort_accelerator">6.16. C code to test the mergesort accelerator</a></li>
<li><a href="#_let_s_do_it_run_the_code_mergesort_code_risc_v_binary">6.17. Let’s do it! Run the <code>mergesort</code> RISC-V binary.</a></li>
<li><a href="#_mergesort_possible_improvements_suggested_exercise">6.18. Mergesort: Possible Improvements (suggested exercise!)</a></li>
</ul>
</li>
<li><a href="#_clocks_concurrency_semantics_performance_and_concurrent_registers">7. Clocks, Concurrency Semantics, Performance, and Concurrent Registers</a>
<ul class="sectlevel2">
<li><a href="#_concurrency_and_parallelism_in_em_bsc_em_generated_hardware_for_rules">7.1. Concurrency and Parallelism in <em>bsc</em>-generated Hardware for Rules</a></li>
<li><a href="#_parallelism_simultaneity_of_actions_in_a_rule">7.2. Parallelism (Simultaneity) of Actions in a Rule</a></li>
<li><a href="#_concurrency_of_rules_within_a_clock">7.3. Concurrency of Rules Within a Clock</a></li>
<li><a href="#_method_ordering_constraints_inducing_conflicts">7.4. Method-ordering Constraints (Inducing “Conflicts”)</a></li>
<li><a href="#_example_of_method_ordering_constraints_on_primitive_registers">7.5. Example of Method-ordering Constraints on Primitive Registers</a></li>
<li><a href="#_from_method_ordering_to_rule_conflicts">7.6. From Method Ordering to Rule Conflicts</a></li>
<li><a href="#_for_conflicts_the_earlier_rule_disables_the_later_rule">7.7. For Conflicts, the Earlier Rule Disables the Later Rule</a></li>
<li><a href="#_summary_of_rule_semantics">7.8. Summary of Rule Semantics</a></li>
<li><a href="#_concurrent_registers_cregs_motivation">7.9. Concurrent Registers (CRegs): Motivation</a></li>
<li><a href="#_concurrent_registers_cregs">7.10. Concurrent Registers (CRegs)</a></li>
<li><a href="#_concurrent_registers_cregs_hardware_implemntation">7.11. Concurrent Registers (CRegs): Hardware Implemntation</a></li>
</ul>
</li>
<li><a href="#_a_word_about_multiple_clocks_and_resets_and_clock_domains_and_reset_domains">8. A Word About Multiple Clocks (and Resets) and Clock Domains (and Reset Domains)</a></li>
<li><a href="#_quality_metrics_for_hardware">9. Quality metrics for hardware</a>
<ul class="sectlevel2">
<li><a href="#_formal_verification">9.1. Formal Verification</a></li>
</ul>
</li>
<li><a href="#_endnote_comparison_with_other_approaches_to_hardware_design">10. Endnote: Comparison with other approaches to hardware-design</a></li>
<li><a href="#_bibliography">11. Bibliography</a></li>
</ul>
</div>
</div>
<div id="content">
<div id="preamble">
<div class="sectionbody">
<div class="paragraph">
<p>Tutorial at ICFP 2020 (25th ACM SIGPLAN International Conference on Functional Programming)</p>
</div>
<div class="paragraph">
<p>Online, August 23, 2020, 14:00h-17:00h EDT</p>
</div>
<hr>
<div class="paragraph">
<p>Tutorial materials at: <a href="https://github.com/rsnikhil/ICFP2020_Bluespec_Tutorial" class="bare">https://github.com/rsnikhil/ICFP2020_Bluespec_Tutorial</a></p>
</div>
<div class="admonitionblock note">
<table>
<tr>
<td class="icon">
<div class="title">Note</div>
</td>
<td class="content">
<strong>Viewing this document</strong>
The source for this document is:<br>
<code>ICFP2020_Bluespec_Tutorial.adoc</code><br>
and there is also an HTML version:<br>
<code>ICFP2020_Bluespec_Tutorial_BH.html</code><br>
The latter is produced from the former using <code>asciidoctor</code>, which is
available in most package installers (e.g., <code>apt-get install asciidoctor</code>).
GitHub and some browsers with <code>asciidoc</code> plug-ins will automatically
process and display the <code>.adoc</code> version when you click to open.
Otherwise, please have your browser display the <code>.html</code> version.
</td>
</tr>
</table>
</div>
<hr>
</div>
</div>
<div class="sect1 center">
<h2 id="_abstract">1. ABSTRACT</h2>
<div class="sectionbody">
<div class="paragraph">
<p>Have you ever considered designing and implementing a piece of digital
hardware, such as an accelerator on an attached FPGA for a complex
computation (Machine Learning, Computer Vision, …​), or just for fun,
but were afraid that hardware design was too far from your wheelhouse?</p>
</div>
<div class="paragraph">
<p>In this tutorial we hope to leverage your knowledge of Haskell to
demystify this, using a lecture + demonstration format which you can
follow along on your laptop during the tutorial. We will use Bluespec
BH, which is a high-level hardware design language using Haskell
syntax and types. BH and its sibling BSV are mature,
industrial-strength hardware design languages, with over 20 years of
development; they have been used to design complex components in
commercial shipping chips. The <code>bsc</code> tool for compiling BH and BSV to
Verilog was open-sourced in January 2020.</p>
</div>
<div class="paragraph">
<p>For background preparation we only assume you know Haskell, and
perhaps nothing about hardware design.</p>
</div>
<div class="paragraph">
<p>We will start with a simple “Hello World!” example, but rapidly climb
through the gears to end with a complete, Linux-capable RISC-V CPU
controlling a pipelined memory-to-memory array-sorting accelerator
(all the materials for this are open-source).</p>
</div>
<div class="paragraph">
<p>At the end of the tutorial, we hope you will:</p>
</div>
<div class="ulist">
<ul>
<li>
<p>Understand how a Haskell-based language (Haskell syntax, Haskell
types) can be used to describe complex hardware system <strong>STRUCTURE</strong>,
and how <em>Guarded Atomic Actions</em> (rewrite rules) can be used to
describe complex hardware system <strong>BEHAVIOR</strong> in a composable way (and
also enabling formal verification).</p>
</li>
<li>
<p>Feel: “I can do this!”, i.e., that you can read and modify the
open-source designs shown in the tutorial, or even create your own
hardware designs.</p>
</li>
</ul>
</div>
<hr>
</div>
</div>
<div class="sect1">
<h2 id="_please_install_the_following">2. Please install the following.</h2>
<div class="sectionbody">
<div class="paragraph">
<p>To study the code and run all the examples in this tutorial, please
install the following (everything here is free and open-source):</p>
</div>
<div class="ulist">
<ul>
<li>
<p>The <code>bsc</code> compiler from <a href="https://github.com/B-Lang-org/bsc" class="bare">https://github.com/B-Lang-org/bsc</a>.</p>
</li>
<li>
<p>The open-source Verilog simulator <code>verilator</code> from
<a href="https://www.veripool.org" class="bare">https://www.veripool.org</a><br></p>
<div class="ulist">
<ul>
<li>
<p>Alternatively, you can install the open-source Verilog
simulator <code>iverilog</code>, available standardly in common package
installers. IVerilog is much slower; it is fine for small
examples, but simulation of large designs is not so pleasant.</p>
</li>
</ul>
</div>
</li>
<li>
<p>The open-source waveform viewer <code>gtkwave</code> (available standardly in
common package installers)</p>
</li>
<li>
<p>Materials for this tutorial, from <a href="https://github.com/rsnikhil/ICFP2020_Bluespec_Tutorial" class="bare">https://github.com/rsnikhil/ICFP2020_Bluespec_Tutorial</a>.</p>
</li>
<li>
<p>The Bluespec <em>Flute</em> open-source RISC-V CPU and <em>WindSoC</em> SoC,
from <a href="https://github.com/bluespec/Flute" class="bare">https://github.com/bluespec/Flute</a>.</p>
</li>
</ul>
</div>
<div class="paragraph">
<p>Ubuntu and Debian Linux are the preferred platforms, but people also use MacOS.</p>
</div>
<hr>
</div>
</div>
<div class="sect1">
<h2 id="_introduction">3. Introduction</h2>
<div class="sectionbody">
<hr>
<div class="sect2">
<h3 id="_why_should_one_design_and_create_hardware">3.1. Why Should One Design and Create Hardware?</h3>
<div class="paragraph">
<p>Any computation can be coded in a programming language and executed on
a general-purpose computing platform (from small single-chip embedded
computers to rack-mounted servers). Much of the world’s hardware
design activity is perhaps indeed about general-purpose computing
platforms.</p>
</div>
<div class="paragraph">
<p>But any computation can also be implemented directly in hardware,
typically with <em>orders of magnitude</em> (often several) advantage in
speed and energy efficiency. Why?</p>
</div>
<div class="ulist">
<ul>
<li>
<p>Removal of one or more layers of interpretation (starting with the
fetch-execute loop of a general-purpose CPU, and possibly more
layers above that)</p>
</li>
<li>
<p>Exploit massive, fine-grain (temporal and spatial) parallelism</p>
</li>
<li>
<p>Exploit massive memory bandwidth due to multiple, distributed, custom memories</p>
</li>
</ul>
</div>
<hr>
<div class="paragraph">
<p><strong>Why Should One Design and Create Hardware?</strong> (Contd.)</p>
</div>
<div class="paragraph">
<p>You servers, laptops and mobile devices already exploit this. Examples:</p>
</div>
<div class="ulist">
<ul>
<li>
<p>Virtual memory address translation and protection</p>
</li>
<li>
<p>Floating point units</p>
</li>
<li>
<p>Graphics</p>
</li>
<li>
<p>Video encoders/decoders</p>
</li>
<li>
<p>Network protocol offload engines (TCP, UDP, …​)</p>
</li>
<li>
<p>Signal processing for wireless communcation, GPS</p>
</li>
</ul>
</div>
<div class="paragraph">
<p><em>Each of these computations can of course be coded in software, but that would not meet speed and/or energy targets.</em></p>
</div>
<div class="paragraph">
<p>More recently, as it becomes increasingly difficult to maintain
Moore’s Law and Dennard Law scaling in silicon we are seeing more and
more “accelerators”:</p>
</div>
<div class="ulist">
<ul>
<li>
<p>Neural nets, Computer Vision, Crypto, Radar/Lidar, …​</p>
</li>
</ul>
</div>
<hr>
</div>
<div class="sect2">
<h3 id="_why_em_shouldn_t_em_one_design_and_create_hardware">3.2. Why <em>Shouldn’t</em> One Design and Create Hardware?</h3>
<div class="paragraph">
<p>It takes a lot of time and effort, and possibly expense; and they’re a lot less flexible:</p>
</div>
<div class="ulist">
<ul>
<li>
<p>ASIC<sup>1</sup> designs take months-to-years to develop, with multi-person teams and millions of dollars.</p>
<div class="ulist">
<ul>
<li>
<p>Only high volume and frequent use justify this.</p>
</li>
</ul>
</div>
</li>
<li>
<p>FPGA<sup>1</sup> designs can take hours-to-months to develop.</p>
<div class="ulist">
<ul>
<li>
<p>(Mostly because their tools are not as highly developed as software compilers and debuggers.)</p>
</li>
</ul>
</div>
</li>
<li>
<p>Hardware designs are typically single-purpose; they’re wasted if not in (frequent) use!</p>
</li>
</ul>
</div>
<div class="paragraph">
<p><sup>1</sup> <em>We’ll demystify “ASIC” and “FPGA” shortly.</em></p>
</div>
<hr>
</div>
<div class="sect2">
<h3 id="_the_flows_processes_for_developing_hardware">3.3. The flows/processes for developing hardware</h3>
<div id="Fig_HW_Dev_Flows" class="imageblock" style="text-align: center">
<div class="content">
<img src="Figures/HW_Dev_Flows.png" alt="HW Dev Flows">
</div>
<div class="title">Figure 1. In this tutorial, we will focus on BH → Simulator, and also describe → FPGA</div>
</div>
<hr>
</div>
<div class="sect2">
<h3 id="_what_is_an_fpga">3.4. What is an FPGA?</h3>
<div id="Fig_FPGA_Model" class="imageblock" style="text-align: center">
<div class="content">
<img src="Figures/FPGA_Model.png" alt="FPGA Model" width="400">
</div>
<div class="title">Figure 2. Simplified model of an FPGA</div>
</div>
<div class="paragraph">
<p>Imagine an FPGA as a pre-built set of components laid out like “Manhattan city blocks”.</p>
</div>
<div class="ulist">
<ul>
<li>
<p>Each block has a collection of AND gates, OR gates, multiplexers (“muxes”), …​<sup>1</sup></p>
</li>
<li>
<p>The “streets” and “avenues” are laid out with wires (“utility cables and pipes”)</p>
</li>
<li>
<p>By making certain connections (red dots in figure), we can connect
an output from one city block to an input in another city block.</p>
</li>
<li>
<p>By choosing these connections, we can make the FPGA look like any circuit we want</p>
</li>
</ul>
</div>
<div class="paragraph">
<p>FPGA tools produce a “bitfile”; each bit is a red dot, i.e., it
controls whether connection is made or not.<br></p>
</div>
<div class="paragraph">
<p><sup>1</sup><strong><em>But don’t worry: we are not going to descend to this ``machine language'' level;
bitfiles are produced for us by FPGA tools (compilers)!</em></strong></p>
</div>
<div class="paragraph">
<p><sup>2</sup><em>More generally, rather than gates, FPGAs provide “LUTs”
(Lookup-Tables) which can themselves be programmed to act like
specific gates or combinational circuits. Other resources include
registers, SRAMs (memories), DSPs (digital signal processors), and
more.</em></p>
</div>
<hr>
</div>
<div class="sect2">
<h3 id="_how_where_can_i_get_an_fpga_and_fpga_asic_tools">3.5. How/Where can I get an FPGA and FPGA/ASIC tools?</h3>
<div class="ulist">
<ul>
<li>
<p>You can buy off-the-shelf “development boards” from FPGA vendors,
which are complete circuit boards containing an FPGA and lots of
surrounding circuitry (DRAM, connectivity such as USB cables, PCIe
connectors, Ethernet, …​)</p>
<div class="ulist">
<ul>
<li>
<p>Boards range from a few tens of dollars to thousands of
dollars, depending on capacity of the FPGA, speed of the FPGA,
resources on the FPGA, resources on the board, etc.</p>
</li>
</ul>
</div>
</li>
<li>
<p>Nowadays cloud-computing providers (e.g., Amazon AWS, Google) allow
you to select “FPGA instances” in the cloud, so that you are
connected to servers that have attached FPGA boards (typically
over PCIe connectors).</p>
</li>
<li>
<p>Sadly, FPGA and ASIC tools are still mostly vendor-proprietary</p>
<div class="ulist">
<ul>
<li>
<p>FPGA tools are often available for free for evaluation, and
with FPGA purchases, and free on cloud platforms.</p>
</li>
<li>
<p>ASIC tools and libraries are expensive, but can be free/cheap for academia.</p>
</li>
<li>
<p><a href="https://www.symbioticeda.com">Symbiotic EDA</a> is one company that
trying to change this (free and open-source tools)</p>
<div class="ulist">
<ul>
<li>
<p>They also do tools and service for <em>formal verification</em> of hardware systems.</p>
</li>
</ul>
</div>
</li>
</ul>
</div>
</li>
</ul>
</div>
<hr>
</div>
<div class="sect2">
<h3 id="_plan_for_this_tutorial">3.6. Plan for this tutorial</h3>
<div class="ulist">
<ul>
<li>
<p>We will start with a simple "Hello World!" example. Like all
Hello-World examples, the purpose is actually to familiarize you
with the “look and feel” of the language, tools and flow.</p>
</li>
<li>
<p>We’ll do a hardware concurrent “Bubblesort” example. Bubblesort
is not a good sorting algorithm, but the purpose here is to
familiarize you with parallelism and concurrency in hardware.</p>
</li>
<li>
<p>We’ll do a hardware, concurrent, highly pipelined, memory-to-memory
“Mergesort” example. Being memory-to-memory, it is capable of
sorting large arrays. We’ll connect this as an “accelerator” in a
small, but complete, Linux-capable, RISC-V CPU-based, “SoC”
(System on a Chip). The CPU is <em>Flute</em> and the SoC is <em>WindSoC</em>.</p>
</li>
</ul>
</div>
<div class="paragraph">
<p><em>All the tools and materials in this tutorial are free and open-source.</em></p>
</div>
<hr>
</div>
<div class="sect2">
<h3 id="_a_note_on_the_em_bsc_em_tool_and_bluespec_bh_and_bsv_code_syntax">3.7. A note on the <em>bsc</em> tool and Bluespec BH and BSV code syntax</h3>
<div class="paragraph">
<p>The central tool we use is <em>bsc</em>, a compiler that converts our source
code into Verilog RTL. It was released as a
<a href="https://github.com/B-Lang-org/bsc">free and open-source tool</a>
in January 2020..</p>
</div>
<div class="paragraph">
<p>The <em>bsc</em> compiler supports two equivalent and interchangeable
source-code syntaxes:</p>
</div>
<div class="dlist">
<dl>
<dt class="hdlist1">BH</dt>
<dd>
<p>Bluespec Haskell, also known as Bluesepec Classic</p>
</dd>
<dt class="hdlist1">BSV</dt>
<dd>
<p>Bluespec SystemVerilog</p>
</dd>
</dl>
</div>
<div class="paragraph">
<p>In this tutorial we use BH, since the ICFP audience is familiar with
Haskell. All the code we show can also be done in BSV.</p>
</div>
<div class="paragraph">
<p>Some of the code we use (in particular the RISC-V CPU and components)
were written in BSV.</p>
</div>
<hr>
</div>
</div>
</div>
<div class="sect1">
<h2 id="_limbering_up_hello_world">4. Limbering up: “Hello World!”</h2>
<div class="sectionbody">
<hr>
<div class="sect2">