From fa35869bc4ee6dd91cff8c5635798127c6c3a17d Mon Sep 17 00:00:00 2001
From: Lior Halphon <LIJI32@gmail.com>
Date: Tue, 11 Oct 2016 13:37:43 +0300
Subject: [PATCH] Implemented DMG STAT-write interrupt bug, fixed Road Rash and
 Zero no Densetsu (These game do not work on CGBs)

---
 Core/memory.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/Core/memory.c b/Core/memory.c
index 28d2a7d..beb9a09 100644
--- a/Core/memory.c
+++ b/Core/memory.c
@@ -433,6 +433,10 @@ static void write_high_memory(GB_gameboy_t *gb, uint16_t addr, uint8_t value)
                 return;
 
             case GB_IO_STAT:
+                /* A DMG bug: http://www.devrs.com/gb/files/faqs.html#GBBugs */
+                if (!gb->is_cgb && (gb->io_registers[GB_IO_STAT] & 0x3) < 2 && (gb->io_registers[GB_IO_LCDC] & 0x80)) {
+                    gb->io_registers[GB_IO_IF] |= 2;
+                }
                 /* Delete previous R/W bits */
                 gb->io_registers[GB_IO_STAT] &= 7;
                 /* Set them by value */