From 0f7d451b18dbfbdb6060cd021dfdd56e199e98b8 Mon Sep 17 00:00:00 2001
From: "Jakob L. Kreuze" <zerodaysfordays@sdf.lonestar.org>
Date: Fri, 27 Dec 2019 17:37:47 -0500
Subject: Implement ADD instruction.

---
 asm.myr | 13 +++++++++++++
 1 file changed, 13 insertions(+)

(limited to 'asm.myr')

diff --git a/asm.myr b/asm.myr
index 0235db5..5fed9b7 100644
--- a/asm.myr
+++ b/asm.myr
@@ -199,6 +199,19 @@ const emitinstr = {p
         | _:
             -> `std.Err(std.fmt("invalid argument to LD: {}", p[1]))
         ;;
+    | "ADD":
+        if p.len < 3
+            -> `std.Err("ADD missing arguments")
+        ;;
+        match (parselit(p[1]), parselit(p[2]))
+        | (`AddressRegister, `Register(n)): b = `std.Some([0xf0 | (n & 0x0f), 0x1e])
+        | (`Register(m), `Number(n)): b = `std.Some([0x70 | (m & 0x0f), n & 0xff])
+        | (`Register(m), `Label(l)): b = `std.Some([0x70 | (m & 0x0f), 0x00])
+            mark = `std.Some(strdup(l))
+        | (`Register(m), `Register(n)): b = `std.Some([0x80 | (m & 0x0f), ((n & 0x0f) << 1) | 0x04])
+        | _:
+            -> `std.Err(std.fmt("invalid argument to ADD: {}", p[1]))
+        ;;
     | _:
         -> `std.Err(std.fmt("unrecognized instruction {}", p[0]))
     ;;
-- 
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