From 76cb3b36be85667750fca6ce15dd5661b4abe47e Mon Sep 17 00:00:00 2001
From: Rerumu <rerumu@protonmail.com>
Date: Wed, 29 Jun 2022 23:55:08 -0400
Subject: [PATCH] Add `i64` sign extension for `i8` and `i16`

---
 codegen/luau/runtime/runtime.lua | 32 ++++++++++++++++++++++++++++++--
 1 file changed, 30 insertions(+), 2 deletions(-)

diff --git a/codegen/luau/runtime/runtime.lua b/codegen/luau/runtime/runtime.lua
index b64820b..c032476 100644
--- a/codegen/luau/runtime/runtime.lua
+++ b/codegen/luau/runtime/runtime.lua
@@ -14,8 +14,8 @@ local function to_i32(num)
 	if num >= 0x80000000 then
 		return num - 0x100000000
 	else
-	return num
-end
+		return num
+	end
 end
 
 local function no_op(num)
@@ -442,6 +442,34 @@ do
 		end
 	end
 
+	function extend.i64_i8(num)
+		local data_1, _ = num_into_u32(num)
+
+		data_1 = bit_and(data_1, 0xFF)
+
+		if data_1 >= 0x80 then
+			local temp = num_from_u32(-data_1 + 0x100, 0)
+
+			return num_negate(temp)
+		else
+			return num_from_u32(data_1, 0)
+		end
+	end
+
+	function extend.i64_i16(num)
+		local data_1, _ = num_into_u32(num)
+
+		data_1 = bit_and(data_1, 0xFFFF)
+
+		if data_1 >= 0x8000 then
+			local temp = num_from_u32(-data_1 + 0x10000, 0)
+
+			return num_negate(temp)
+		else
+			return num_from_u32(data_1, 0)
+		end
+	end
+
 	function extend.i64_i32(num)
 		if num >= 0x80000000 then
 			local temp = num_from_u32(-num + 0x100000000, 0)