@@ -18,6 +18,7 @@ #include <mgba/internal/ds/gx.h>
 #include <mgba/internal/ds/memory.h>
 #include <mgba/internal/ds/timer.h>
 #include <mgba/internal/ds/video.h>
+#include <mgba/internal/ds/wifi.h>
 
 extern const uint32_t DS_ARM946ES_FREQUENCY;
 extern const uint32_t DS_ARM7TDMI_FREQUENCY;
@@ -85,6 +86,7 @@ struct DSCommon ds9;
 	struct DSMemory memory;
 	struct DSVideo video;
 	struct DSGX gx;
+	struct DSWifi wifi;
 
 	struct mCoreSync* sync;
 	struct mTimingEvent slice;

@@ -122,6 +122,9 @@ DS7_REG_BIOSPROT_LO = 0x308,
 	DS7_REG_BIOSPROT_HI = 0x30A,
 
 	DS7_REG_MAX = 0x51E,
+
+	DS7_IO_BASE_WIFI = 0x800000,
+	DS7_IO_END_WIFI = 0x810000,
 };
 
 enum DS9IORegisters {

@@ -0,0 +1,30 @@
+/* Copyright (c) 2013-2017 Jeffrey Pfau
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+#ifndef DS_WIFI_H
+#define DS_WIFI_H
+
+#include <mgba-util/common.h>
+
+CXX_GUARD_START
+
+#include <mgba/core/log.h>
+
+mLOG_DECLARE_CATEGORY(DS_WIFI);
+
+struct DSWifi {
+	uint16_t io[0x800];
+	uint16_t wram[0x1000];
+	uint8_t baseband[0x100];
+};
+
+struct DS;
+void DSWifiReset(struct DS* ds);
+void DSWifiWriteIO(struct DS* ds, uint32_t address, uint16_t value);
+uint16_t DSWifiReadIO(struct DS* ds, uint32_t address);
+
+CXX_GUARD_END
+
+#endif

@@ -282,6 +282,10 @@ } else if (v2 & 0x20000) {
 				return;
 			}
 		}
+		if (address >= DS7_IO_BASE_WIFI && address < DS7_IO_END_WIFI) {
+			DSWifiWriteIO(ds, address & 0x7FFF, value);
+			return;
+		}
 		mLOG(DS_IO, STUB, "Stub DS7 I/O register write: %06X:%04X", address, value);
 		if (address >= DS7_REG_MAX) {
 			mLOG(DS_IO, GAME_ERROR, "Write to unused DS7 I/O register: %06X:%04X", address, value);
@@ -391,11 +395,15 @@ mLOG(DS_IO, GAME_ERROR, "Invalid cart access");
 			return 0;
 		}
 	default:
+		if (address >= DS7_IO_BASE_WIFI && address < DS7_IO_END_WIFI) {
+			return DSWifiReadIO(ds, address & 0x7FFF);
+		}
 		mLOG(DS_IO, STUB, "Stub DS7 I/O register read: %06X", address);
 	}
 	if (address < DS7_REG_MAX) {
 		return ds->memory.io7[address >> 1];
 	}
+
 	return 0;
 }
 

@@ -0,0 +1,88 @@
+/* Copyright (c) 2013-2017 Jeffrey Pfau
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+#include <mgba/internal/ds/wifi.h>
+
+#include <mgba/internal/arm/macros.h>
+#include <mgba/internal/ds/ds.h>
+
+mLOG_DEFINE_CATEGORY(DS_WIFI, "DS Wi-Fi", "ds.wifi");
+
+void DSWifiReset(struct DS* ds) {
+	memset(ds->wifi.io, 0, sizeof(ds->wifi.io));
+	memset(ds->wifi.wram, 0, sizeof(ds->wifi.wram));
+}
+
+static void DSWifiWriteBB(struct DS* ds, uint8_t address, uint8_t value) {
+	mLOG(DS_WIFI, STUB, "Stub Wi-Fi baseband register write: %02X:%02X", address, value);
+	ds->wifi.baseband[address] = value;
+}
+
+static uint8_t DSWifiReadBB(struct DS* ds, uint8_t address) {
+	mLOG(DS_WIFI, STUB, "Stub Wi-Fi baseband register read: %02X", address);
+	return ds->wifi.baseband[address];
+}
+
+static void DSWifiWriteReg(struct DS* ds, uint32_t address, uint16_t value) {
+	switch (address) {
+	case 0x158:
+		if (value & 0x1000) {
+			DSWifiWriteBB(ds, value & 0xFF, ds->wifi.io[0x15A >> 1]);
+		}
+		if (value & 0x2000) {
+			ds->wifi.io[0x15C >> 1] = DSWifiReadBB(ds, value & 0xFF);
+		}
+		break;
+	case 0x15A:
+		break;
+	default:
+		mLOG(DS_WIFI, STUB, "Stub Wi-Fi I/O register write: %06X:%04X", address, value);
+		break;
+	}
+	ds->wifi.io[address >> 1] = value;
+}
+
+static uint16_t DSWifiReadReg(struct DS* ds, uint32_t address) {
+	switch (address) {
+	case 0x15C:
+		break;
+	default:
+		mLOG(DS_WIFI, STUB, "Stub Wi-Fi I/O register read: %06X", address);
+		break;
+	}
+	return ds->wifi.io[address >> 1];
+}
+
+void DSWifiWriteIO(struct DS* ds, uint32_t address, uint16_t value) {
+	switch (address >> 12) {
+	case 0:
+	case 1:
+	case 6:
+	case 7:
+		DSWifiWriteReg(ds, address & 0xFFF, value);
+		break;
+	case 4:
+	case 5:
+		STORE_16(value, address & 0x1FFE, ds->wifi.wram);
+		break;
+	}
+}
+
+uint16_t DSWifiReadIO(struct DS* ds, uint32_t address) {
+	uint16_t value = 0;
+	switch (address >> 12) {
+	case 0:
+	case 1:
+	case 6:
+	case 7:
+		value = DSWifiReadReg(ds, address & 0xFFF);
+		break;
+	case 4:
+	case 5:
+		LOAD_16(value, address & 0x1FFE, ds->wifi.wram);
+		break;
+	}
+	return value;
+}