From 82990fdab78a01248e3a10c9ce8c44d9729ad2a1 Mon Sep 17 00:00:00 2001
From: Takashi Toyoshima <toyoshim@gmail.com>
Date: Mon, 8 Dec 2014 00:40:40 +0900
Subject: [PATCH] Bug fix: B and reserved flag should not be modified on
 updating SR

---
 6502.S | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/6502.S b/6502.S
index ef0f76d..104cce2 100644
--- a/6502.S
+++ b/6502.S
@@ -30,6 +30,8 @@
 
 #define FLAG_N (1 << 7)
 #define FLAG_V (1 << 6)
+#define FLAG_X (1 << 5)
+#define FLAG_B (1 << 4)
 #define FLAG_D (1 << 3)
 #define FLAG_I (1 << 2)
 #define FLAG_Z (1 << 1)
@@ -927,6 +929,7 @@ op26:  // ROR - Zero Page
 op28:  // PLP
   _popb
   mov  SR, r0
+  __se (FLAG_X | FLAG_B)
   adds PC, PC, #1
   _decode