From afc0a9df57907264fb7526ba9065c9e1cf944022 Mon Sep 17 00:00:00 2001
From: Jeffrey Pfau <jeffrey@endrift.com>
Date: Wed, 7 Jan 2015 22:18:08 -0800
Subject: [PATCH] GBA BIOS: Implement (most of) RegisterRamReset

---
 CHANGES            |  2 +-
 src/gba/gba-bios.c | 28 ++++++++++++++++++++++++++--
 2 files changed, 27 insertions(+), 3 deletions(-)

diff --git a/CHANGES b/CHANGES
index 57080449d..0cb62ea34 100644
--- a/CHANGES
+++ b/CHANGES
@@ -14,7 +14,7 @@ Features:
  - Support for games using the tilt sensor
  - Remappable shortcuts for keyboard and gamepad
  - Rewinding of emulation
- - Implemented BIOS routines Diff8bitUnFilterWram, Diff8bitUnFilterVram, and Diff16bitUnFilter
+ - Implemented BIOS routines RegisterRamReset, Diff8bitUnFilterWram, Diff8bitUnFilterVram, and Diff16bitUnFilter
 Bugfixes:
  - Qt: Fix issue with set frame sizes being the wrong height
  - Qt: Fix emulator crashing when full screen if a game is not running
diff --git a/src/gba/gba-bios.c b/src/gba/gba-bios.c
index 5f3ad806d..16d112138 100644
--- a/src/gba/gba-bios.c
+++ b/src/gba/gba-bios.c
@@ -19,8 +19,32 @@ static void _unFilter(struct GBA* gba, int inwidth, int outwidth);
 
 static void _RegisterRamReset(struct GBA* gba) {
 	uint32_t registers = gba->cpu->gprs[0];
-	UNUSED(registers);
-	GBALog(gba, GBA_LOG_STUB, "RegisterRamReset unimplemented");
+	struct ARMCore* cpu = gba->cpu;
+	cpu->memory.store16(cpu, BASE_IO | REG_DISPCNT, 0x0080, 0);
+	if (registers & 0x01) {
+		memset(gba->memory.wram, 0, SIZE_WORKING_RAM);
+	}
+	if (registers & 0x02) {
+		memset(gba->memory.iwram, 0, SIZE_WORKING_IRAM - 0x200);
+	}
+	if (registers & 0x04) {
+		memset(gba->video.palette, 0, SIZE_PALETTE_RAM);
+	}
+	if (registers & 0x08) {
+		memset(gba->video.renderer->vram, 0, SIZE_VRAM);
+	}
+	if (registers & 0x10) {
+		memset(gba->video.oam.raw, 0, SIZE_OAM);
+	}
+	if (registers & 0x20) {
+		GBALog(gba, GBA_LOG_STUB, "RegisterRamReset on SIO unimplemented");
+	}
+	if (registers & 0x40) {
+		GBALog(gba, GBA_LOG_STUB, "RegisterRamReset on Audio unimplemented");
+	}
+	if (registers & 0x80) {
+		GBALog(gba, GBA_LOG_STUB, "RegisterRamReset on IO unimplemented");
+	}
 }
 
 static void _BgAffineSet(struct GBA* gba) {