From efc5c9354f36e164f614299a770f2ea2b21d11bd Mon Sep 17 00:00:00 2001
From: Rerumu <rerumu@protonmail.com>
Date: Sat, 25 Jun 2022 22:51:45 -0400
Subject: [PATCH] Fix copysign

---
 codegen/luau/runtime/runtime.lua | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/codegen/luau/runtime/runtime.lua b/codegen/luau/runtime/runtime.lua
index d1dc423..5812e1f 100644
--- a/codegen/luau/runtime/runtime.lua
+++ b/codegen/luau/runtime/runtime.lua
@@ -43,6 +43,7 @@ do
 	local nearest = {}
 
 	local assert = assert
+
 	local math_abs = math.abs
 	local math_floor = math.floor
 	local math_round = math.round
@@ -50,6 +51,9 @@ do
 	local math_max = math.max
 	local math_min = math.min
 
+	local string_byte = string.byte
+	local string_pack = string.pack
+
 	function add.i32(a, b)
 		return to_u32(a + b)
 	end
@@ -108,8 +112,11 @@ do
 	end
 
 	function copysign.f32(lhs, rhs)
-		if rhs >= 0 then
-			return (math_abs(lhs))
+		local packed = string_pack("d", rhs)
+		local sign = string_byte(packed, 8)
+
+		if sign < 0x80 then
+			return math_abs(lhs)
 		else
 			return -math_abs(lhs)
 		end