From a3519baa935ea9c26cec2ab838b0e38b7a1d8070 Mon Sep 17 00:00:00 2001
From: EkeEke <ekeeke31@gmail.com>
Date: Sat, 2 Feb 2013 02:32:40 +0100
Subject: [PATCH] [SCD] fixed & improved emulation of PRG-RAM write protection
 register (broken by previous revision): fixes Lunar - Eternal Blue (J)

---
 source/cd_hw/scd.c | 6 ++++++
 source/mem68k.c    | 6 ++++++
 2 files changed, 12 insertions(+)

diff --git a/source/cd_hw/scd.c b/source/cd_hw/scd.c
index c8b6574..8ec9347 100644
--- a/source/cd_hw/scd.c
+++ b/source/cd_hw/scd.c
@@ -92,6 +92,12 @@ void prg_ram_dma_w(unsigned int words)
   /* update DMA source address */
   cdc.dac.w += (words << 1);
 
+  /* check PRG-RAM write protected area */
+  if (dst_index < (scd.regs[0x02>>1].byte.h << 9))
+  {
+    return;
+  }
+
   /* DMA transfer */
   while (words--)
   {
diff --git a/source/mem68k.c b/source/mem68k.c
index 499cceb..5798d75 100644
--- a/source/mem68k.c
+++ b/source/mem68k.c
@@ -650,6 +650,12 @@ void ctrl_io_write_byte(unsigned int address, unsigned int data)
             return;
           }
 
+          case 0x02:  /* PRG-RAM Write Protection */
+          {
+            scd.regs[0x02>>1].byte.h = data;
+            return;
+          }
+
           case 0x03:  /* Memory mode */
           {
             m68k_poll_sync(0x02);