From 2817db4e1c587c89be683b79f1fbbe01a06693b5 Mon Sep 17 00:00:00 2001
From: Michel Heily <michelheily@gmail.com>
Date: Tue, 9 Jul 2019 00:30:23 +0300
Subject: [PATCH] alu: Fix carry detection for subtraction

Former-commit-id: c9d8612f72ce4a002ea33446209bd7e6da0eb5aa
---
 src/arm7tdmi/alu.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/arm7tdmi/alu.rs b/src/arm7tdmi/alu.rs
index 4598a85..7ab9ead 100644
--- a/src/arm7tdmi/alu.rs
+++ b/src/arm7tdmi/alu.rs
@@ -201,7 +201,7 @@ impl Core {
 
     fn alu_sub_flags(a: i32, b: i32, carry: &mut bool, overflow: &mut bool) -> i32 {
         let res = a.wrapping_sub(b);
-        *carry = res > a;
+        *carry = b <= a;
         let (_, would_overflow) = a.overflowing_sub(b);
         *overflow = would_overflow;
         res