diff --git a/beautiful-racket/br/demo/hdl/tst.rkt b/beautiful-racket/br/demo/hdl-tst.rkt
similarity index 53%
rename from beautiful-racket/br/demo/hdl/tst.rkt
rename to beautiful-racket/br/demo/hdl-tst.rkt
index 3afdaf3..eeca7a3 100644
--- a/beautiful-racket/br/demo/hdl/tst.rkt
+++ b/beautiful-racket/br/demo/hdl-tst.rkt
@@ -1,7 +1,7 @@
 #lang br
 
 (module reader br
-  (require br/reader-utils "tst/parser.rkt" "tst/tokenizer.rkt")
+  (require br/reader-utils "hdl-tst/parser.rkt" "hdl-tst/tokenizer.rkt")
   (define-read-and-read-syntax (source-path input-port)
-    #`(module hdl-mod br/demo/hdl/tst/expander
+    #`(module hdl-mod br/demo/hdl-tst/expander
         #,(parse source-path (tokenize input-port)))))
diff --git a/beautiful-racket/br/demo/hdl/tst/expander.rkt b/beautiful-racket/br/demo/hdl-tst/expander.rkt
similarity index 94%
rename from beautiful-racket/br/demo/hdl/tst/expander.rkt
rename to beautiful-racket/br/demo/hdl-tst/expander.rkt
index 17e189d..3639879 100644
--- a/beautiful-racket/br/demo/hdl/tst/expander.rkt
+++ b/beautiful-racket/br/demo/hdl-tst/expander.rkt
@@ -19,7 +19,7 @@
                   [#'output (shared-syntax 'output)])
     #'(begin
         (provide (all-defined-out))
-        (define shared-procname (dynamic-require _filename-string 'shared-procname))
+        (define shared-procname (dynamic-require (findf file-exists? (list _filename-string (format "~a.rkt" _filename-string))) 'shared-procname))
         (display-header '_colid ... '_outid)
         (define _colid (make-parameter 0)) ...
         (define (_outid)
diff --git a/beautiful-racket/br/demo/hdl-tst/hdlprint.rkt b/beautiful-racket/br/demo/hdl-tst/hdlprint.rkt
new file mode 100644
index 0000000..cf1c527
--- /dev/null
+++ b/beautiful-racket/br/demo/hdl-tst/hdlprint.rkt
@@ -0,0 +1,19 @@
+#lang racket
+
+
+(define (hdlprint val fmt)
+  (match-define (list _ radix-letter number-strings) (regexp-match #px"^%(.)(.*)$" fmt)) ; like %B1.16.1
+  (match-define (list left-margin width right-margin) (map string->number (string-split number-strings ".")))
+  (define radix (case radix-letter
+                  [("B") 2]))
+  (string-append (make-string left-margin #\space)
+                 (if (number? val)
+                     (~r val #:min-width width #:pad-string "0" #:base radix)
+                     (~a val #:min-width width #:pad-string " " #:align 'center))
+                 (make-string right-margin #\space)))
+
+(module+ test
+(require rackunit)
+(define a 123)
+(check-equal? (hdlprint a "%B1.16.1") " 0000000001111011 ")
+(check-equal? (hdlprint "out" "%B1.16.1") "       out        "))
diff --git a/beautiful-racket/br/demo/hdl/tst/parser.rkt b/beautiful-racket/br/demo/hdl-tst/parser.rkt
similarity index 100%
rename from beautiful-racket/br/demo/hdl/tst/parser.rkt
rename to beautiful-racket/br/demo/hdl-tst/parser.rkt
diff --git a/beautiful-racket/br/demo/hdl/tst/tokenizer.rkt b/beautiful-racket/br/demo/hdl-tst/tokenizer.rkt
similarity index 100%
rename from beautiful-racket/br/demo/hdl/tst/tokenizer.rkt
rename to beautiful-racket/br/demo/hdl-tst/tokenizer.rkt
diff --git a/beautiful-racket/br/demo/hdl/And.hdl b/beautiful-racket/br/demo/hdl/And.hdl.rkt
similarity index 100%
rename from beautiful-racket/br/demo/hdl/And.hdl
rename to beautiful-racket/br/demo/hdl/And.hdl.rkt
diff --git a/beautiful-racket/br/demo/hdl/And.tst b/beautiful-racket/br/demo/hdl/And.tst
index 9e35d74..0eed34b 100644
--- a/beautiful-racket/br/demo/hdl/And.tst
+++ b/beautiful-racket/br/demo/hdl/And.tst
@@ -1,4 +1,4 @@
-#lang br/demo/hdl/tst
+#lang br/demo/hdl-tst
 
 /* and */