chore: add macro to simplify constructing opcodes

host/assembler/opcodes.fnl

@@ -77,19 +77,19 @@
   (let [{: cond} (parse-conditions ?options)
         max-immediate 0xffffff
         offset (band offset util.word-max)]
-    (bor
-      (lshift cond 28)
-      (lshift 10 24)
-      (band (rshift offset 2) 0xffffff))))
+    (construct-opcode
+      (cond 28)
+      (10 24)
+      ((band (rshift offset 2) 0xffffff) 0))))
 
 (fn branch-link [offset ?options]
   (let [{: cond} (parse-conditions ?options)
         max-immediate 0xffffff
         offset (band offset util.word-max)]
-    (bor
-      (lshift cond 28)
-      (lshift 11 24)
-      (band (rshift offset 2) 0xffffff))))
+    (construct-opcode
+      (cond 28)
+      (11 24)
+      ((band (rshift offset 2) 0xffffff) 0))))
 
 {: r
  : move

test/assembler/opcodes.fnl

@@ -1,6 +1,5 @@
 (local t (require :deps.faith))
-(local {: r : move} (require :host.assembler.opcodes))
-
+(local {: r : move : branch : branch-link} (require :host.assembler.opcodes))
 (fn hex [n]
   "format a number as 32 bit hexadecimal"
   (string.format :0x%08x n))
@@ -11,4 +10,12 @@
   (t.= 0xe3a05003
        (move (r 5) 3)))
 
-{: test-move}
+(fn test-branch []
+  (t.= 0xea000021
+       (branch 132)))
+
+(fn test-branch-link []
+  (t.= 0xeb000021
+       (branch-link 132)))
+
+{: test-move : test-branch : test-branch-link}