From 0da0a54b7404c2ad0a1a066309fa58f3dd37a559 Mon Sep 17 00:00:00 2001
From: Fey Naomi Schrewe <fey@posteo.eu>
Date: Fri, 17 Oct 2025 09:13:11 +0200
Subject: [PATCH] chore: add macro to simplify constructing opcodes

---
 host/assembler/opcodes.fnl | 28 ++++++++++++++--------------
 test.fnl                   |  5 +++++
 test/assembler/opcodes.fnl | 13 ++++++++++++-
 3 files changed, 31 insertions(+), 15 deletions(-)
 create mode 100644 test.fnl

diff --git a/host/assembler/opcodes.fnl b/host/assembler/opcodes.fnl
index c33912e..1903cf0 100644
--- a/host/assembler/opcodes.fnl
+++ b/host/assembler/opcodes.fnl
@@ -56,22 +56,22 @@
         dest (register? dest)]
     (when (not dest) (error "dest must be a register"))
     (if source-register
-      (bor 
-        (lshift cond 28)
-        (lshift 0xd 21)
-        (lshift set-flags 20)
-        (lshift dest 12)
-        source-register)
+      (construct-opcode
+        [cond 28]
+        [0xd 21]
+        [set-flags 20]
+        [dest 12]
+        [source-register 0])
       (let [rotation (calculate-rotation source)]
         (when (= nil rotation) (error "Unencodable immediate value"))
-        (bor 
-          (lshift cond 28)
-          (lshift 1 25)
-          (lshift 0xd 21)
-          (lshift set-flags 20)
-          (lshift dest 12)
-          (lshift (/ rotation 2) 8)
-          (band (util.rotate-left source rotation) 0xff))))))
+        (construct-opcode
+          (cond 28)
+          (1 25)
+          (0xd 21)
+          (set-flags 20)
+          (dest 12)
+          ((/ rotation 2) 8)
+          ((band (util.rotate-left source rotation) 0xff) 0))))))
 
 (fn branch [offset ?options]
   (let [{: cond} (parse-conditions ?options)
diff --git a/test.fnl b/test.fnl
new file mode 100644
index 0000000..7c33156
--- /dev/null
+++ b/test.fnl
@@ -0,0 +1,5 @@
+(local t (require :deps.faith))
+
+(local default-modules [:test.assembler.opcodes])
+
+(t.run (if (= 0 (length arg)) default-modules arg))
diff --git a/test/assembler/opcodes.fnl b/test/assembler/opcodes.fnl
index 841f1ea..3a510ef 100644
--- a/test/assembler/opcodes.fnl
+++ b/test/assembler/opcodes.fnl
@@ -1,2 +1,13 @@
 (local t (require :deps.faith))
-(local opcodes (require :host.assembler.opcodes))
+(local {: r : move} (require :host.assembler.opcodes))
+(fn hex [n]
+  "format a number as 32 bit hexadecimal"
+  (string.format :0x%08x n))
+
+(fn test-move []
+  (t.= 0xe1a05003
+       (move (r 5) (r 3)))
+  (t.= 0xe3a05003
+       (move (r 5) 3)))
+
+{: test-move}