diff --git a/rpcs3/Emu/SysCalls/Modules/cellGcmSys.cpp b/rpcs3/Emu/SysCalls/Modules/cellGcmSys.cpp
index 73c6065272..9c31b9130d 100644
--- a/rpcs3/Emu/SysCalls/Modules/cellGcmSys.cpp
+++ b/rpcs3/Emu/SysCalls/Modules/cellGcmSys.cpp
@@ -5,6 +5,8 @@
 #include "Emu/SysCalls/Modules.h"
 #include "Emu/SysCalls/SysCalls.h"
 #include "Emu/GS/GCM.h"
+#include "sysPrxForUser.h"
+#include "cellGcmSys.h"
 
 //void cellGcmSys_init();
 //void cellGcmSys_load();
@@ -12,48 +14,22 @@
 //Module cellGcmSys(0x0010, cellGcmSys_init, cellGcmSys_load, cellGcmSys_unload);
 Module *cellGcmSys = nullptr;
 
+const u32 tiled_pitches[] = {
+	0x00000000, 0x00000200, 0x00000300, 0x00000400,
+	0x00000500, 0x00000600, 0x00000700, 0x00000800,
+	0x00000A00, 0x00000C00, 0x00000D00, 0x00000E00,
+	0x00001000, 0x00001400, 0x00001800, 0x00001A00,
+	0x00001C00, 0x00002000, 0x00002800, 0x00003000,
+	0x00003400, 0x00003800, 0x00004000, 0x00005000,
+	0x00006000, 0x00006800, 0x00007000, 0x00008000,
+	0x0000A000, 0x0000C000, 0x0000D000, 0x0000E000,
+	0x00010000
+};
+
 u32 local_size = 0;
 u32 local_addr = 0;
 u32 system_mode = 0;
 
-enum
-{
-	CELL_GCM_ERROR_FAILURE           = 0x802100ff,
-	CELL_GCM_ERROR_NO_IO_PAGE_TABLE  = 0x80210001,
-	CELL_GCM_ERROR_INVALID_ENUM      = 0x80210002,
-	CELL_GCM_ERROR_INVALID_VALUE     = 0x80210003,
-	CELL_GCM_ERROR_INVALID_ALIGNMENT = 0x80210004,
-	CELL_GCM_ERROR_ADDRESS_OVERWRAP  = 0x80210005
-};
-
-// Function declaration 
-int cellGcmSetPrepareFlip(mem_ptr_t<CellGcmContextData> ctxt, u32 id);
-
-//----------------------------------------------------------------------------
-// Memory Mapping
-//----------------------------------------------------------------------------
-
-struct gcm_offset
-{
-	u64 io;
-	u64 ea;
-};
-
-void InitOffsetTable();
-int32_t cellGcmAddressToOffset(u64 address, mem32_t offset);
-uint32_t cellGcmGetMaxIoMapSize();
-void cellGcmGetOffsetTable(mem_ptr_t<gcm_offset> table);
-int32_t cellGcmIoOffsetToAddress(u32 ioOffset, u64 address);
-int32_t cellGcmMapEaIoAddress(const u32 ea, const u32 io, const u32 size);
-int32_t cellGcmMapEaIoAddressWithFlags(const u32 ea, const u32 io, const u32 size, const u32 flags);
-int32_t cellGcmMapMainMemory(u64 ea, u32 size, mem32_t offset);
-int32_t cellGcmReserveIoMapSize(const u32 size);
-int32_t cellGcmUnmapEaIoAddress(u64 ea);
-int32_t cellGcmUnmapIoAddress(u64 io);
-int32_t cellGcmUnreserveIoMapSize(u32 size);
-
-//----------------------------------------------------------------------------
-
 CellGcmConfig current_config;
 CellGcmContextData current_context;
 gcmInfo gcm_info;
@@ -287,10 +263,14 @@ int cellGcmGetFlipStatus()
 
 u32 cellGcmGetTiledPitchSize(u32 size)
 {
-	cellGcmSys->Warning("cellGcmGetTiledPitchSize(size=%d)", size);
-	// TODO:
+	cellGcmSys->Log("cellGcmGetTiledPitchSize(size=%d)", size);
 
-	return size;
+	for (size_t i=0; i < sizeof(tiled_pitches)/sizeof(tiled_pitches[0]) - 1; i++) {
+		if (tiled_pitches[i] < size && size <= tiled_pitches[i+1]) {
+			return tiled_pitches[i+1];
+		}
+	}
+	return 0;
 }
 
 int cellGcmInit(u32 context_addr, u32 cmdSize, u32 ioSize, u32 ioAddress)
@@ -467,7 +447,7 @@ void cellGcmSetFlipStatus()
 	Emu.GetGSManager().GetRender().m_flip_status = 0;
 }
 
-int cellGcmSetPrepareFlip(mem_ptr_t<CellGcmContextData> ctxt, u32 id)
+s32 cellGcmSetPrepareFlip(mem_ptr_t<CellGcmContextData> ctxt, u32 id)
 {
 	cellGcmSys->Log("cellGcmSetPrepareFlip(ctx=0x%x, id=0x%x)", ctxt.GetAddr(), id);
 
@@ -808,7 +788,7 @@ void InitOffsetTable()
 	}
 }
 
-int32_t cellGcmAddressToOffset(u64 address, mem32_t offset)
+s32 cellGcmAddressToOffset(u64 address, mem32_t offset)
 {
 	cellGcmSys->Log("cellGcmAddressToOffset(address=0x%x,offset_addr=0x%x)", address, offset.GetAddr());
 
@@ -827,14 +807,11 @@ int32_t cellGcmAddressToOffset(u64 address, mem32_t offset)
 	{
 		u16 upper12Bits = Memory.Read16(offsetTable.io + sizeof(u16)*(address >> 20));
 
-		if (upper12Bits != 0xFFFF)
-		{
+		if (upper12Bits != 0xFFFF) {
 			result = (((u64)upper12Bits << 20) | (address & (0xFFFFF)));
 		}
 		// address is not mapped in IO
-		else
-		{
-
+		else {
 			return CELL_GCM_ERROR_FAILURE;
 		}
 	}
@@ -843,7 +820,7 @@ int32_t cellGcmAddressToOffset(u64 address, mem32_t offset)
 	return CELL_OK;
 }
 
-uint32_t cellGcmGetMaxIoMapSize()
+u32 cellGcmGetMaxIoMapSize()
 {
 	return Memory.RSXIOMem.GetEndAddr() - Memory.RSXIOMem.GetStartAddr() - Memory.RSXIOMem.GetReservedAmount();
 }
@@ -854,7 +831,7 @@ void cellGcmGetOffsetTable(mem_ptr_t<gcm_offset> table)
 	table->ea = re(offsetTable.ea);
 }
 
-int32_t cellGcmIoOffsetToAddress(u32 ioOffset, u64 address)
+s32 cellGcmIoOffsetToAddress(u32 ioOffset, u64 address)
 {
 	u64 realAddr;
 
@@ -866,7 +843,7 @@ int32_t cellGcmIoOffsetToAddress(u32 ioOffset, u64 address)
 	return CELL_OK;
 }
 
-int32_t cellGcmMapEaIoAddress(const u32 ea, const u32 io, const u32 size)
+s32 cellGcmMapEaIoAddress(u32 ea, u32 io, u32 size)
 {
 	cellGcmSys->Warning("cellGcmMapEaIoAddress(ea=0x%x, io=0x%x, size=0x%x)", ea, io, size);
 
@@ -891,13 +868,13 @@ int32_t cellGcmMapEaIoAddress(const u32 ea, const u32 io, const u32 size)
 	return CELL_OK;
 }
 
-int32_t cellGcmMapEaIoAddressWithFlags(const u32 ea, const u32 io, const u32 size, const u32 flags)
+s32 cellGcmMapEaIoAddressWithFlags(u32 ea, u32 io, u32 size, u32 flags)
 {
 	cellGcmSys->Warning("cellGcmMapEaIoAddressWithFlags(ea=0x%x, io=0x%x, size=0x%x, flags=0x%x)", ea, io, size, flags);
 	return cellGcmMapEaIoAddress(ea, io, size); // TODO: strict ordering
 }
 
-int32_t cellGcmMapLocalMemory(u64 address, u64 size)
+s32 cellGcmMapLocalMemory(u64 address, u64 size)
 {
 	if (!local_size && !local_addr)
 	{
@@ -916,7 +893,7 @@ int32_t cellGcmMapLocalMemory(u64 address, u64 size)
 	return CELL_OK;
 }
 
-int32_t cellGcmMapMainMemory(u64 ea, u32 size, mem32_t offset)
+s32 cellGcmMapMainMemory(u64 ea, u32 size, mem32_t offset)
 {
 	cellGcmSys->Warning("cellGcmMapMainMemory(ea=0x%x,size=0x%x,offset_addr=0x%x)", ea, size, offset.GetAddr());
 
@@ -950,7 +927,7 @@ int32_t cellGcmMapMainMemory(u64 ea, u32 size, mem32_t offset)
 	return CELL_OK;
 }
 
-int32_t cellGcmReserveIoMapSize(const u32 size)
+s32 cellGcmReserveIoMapSize(u32 size)
 {
 	if (size & 0xFFFFF)
 	{
@@ -968,7 +945,7 @@ int32_t cellGcmReserveIoMapSize(const u32 size)
 	return CELL_OK;
 }
 
-int32_t cellGcmUnmapEaIoAddress(u64 ea)
+s32 cellGcmUnmapEaIoAddress(u64 ea)
 {
 	u32 size = Memory.RSXIOMem.UnmapRealAddress(ea);
 	if (size)
@@ -992,7 +969,7 @@ int32_t cellGcmUnmapEaIoAddress(u64 ea)
 	return CELL_OK;
 }
 
-int32_t cellGcmUnmapIoAddress(u64 io)
+s32 cellGcmUnmapIoAddress(u64 io)
 {
 	u32 size = Memory.RSXIOMem.UnmapAddress(io);
 	if (size)
@@ -1016,7 +993,7 @@ int32_t cellGcmUnmapIoAddress(u64 io)
 	return CELL_OK;
 }
 
-int32_t cellGcmUnreserveIoMapSize(u32 size)
+s32 cellGcmUnreserveIoMapSize(u32 size)
 {
 
 	if (size & 0xFFFFF)
@@ -1094,9 +1071,15 @@ int cellGcmSetFlipCommand(u32 ctx, u32 id)
 	return cellGcmSetPrepareFlip(ctx, id);
 }
 
-s64 cellGcmFunc15()
+s64 cellGcmFunc15(u32 unk_addr)
 {
-	cellGcmSys->Todo("cellGcmFunc15()");
+	cellGcmSys->Todo("cellGcmFunc15(unk_addr=0x%x)", unk_addr);
+
+	if (0/*TODO: If what?*/) {
+		_sys_memset(unk_addr, 0, 0x84);
+	}
+
+	// TODO
 	return 0;
 }
 
diff --git a/rpcs3/Emu/SysCalls/Modules/cellGcmSys.h b/rpcs3/Emu/SysCalls/Modules/cellGcmSys.h
new file mode 100644
index 0000000000..610b177edc
--- /dev/null
+++ b/rpcs3/Emu/SysCalls/Modules/cellGcmSys.h
@@ -0,0 +1,35 @@
+#pragma once
+
+enum
+{
+	CELL_GCM_ERROR_FAILURE           = 0x802100ff,
+	CELL_GCM_ERROR_NO_IO_PAGE_TABLE  = 0x80210001,
+	CELL_GCM_ERROR_INVALID_ENUM      = 0x80210002,
+	CELL_GCM_ERROR_INVALID_VALUE     = 0x80210003,
+	CELL_GCM_ERROR_INVALID_ALIGNMENT = 0x80210004,
+	CELL_GCM_ERROR_ADDRESS_OVERWRAP  = 0x80210005
+};
+
+struct gcm_offset
+{
+	u64 io;
+	u64 ea;
+};
+
+// Auxiliary functions
+void InitOffsetTable();
+
+// SysCalls
+s32 cellGcmSetPrepareFlip(mem_ptr_t<CellGcmContextData> ctxt, u32 id);
+
+s32 cellGcmAddressToOffset(u64 address, mem32_t offset);
+u32 cellGcmGetMaxIoMapSize();
+void cellGcmGetOffsetTable(mem_ptr_t<gcm_offset> table);
+s32 cellGcmIoOffsetToAddress(u32 ioOffset, u64 address);
+s32 cellGcmMapEaIoAddress(u32 ea, u32 io, u32 size);
+s32 cellGcmMapEaIoAddressWithFlags(u32 ea, u32 io, u32 size, u32 flags);
+s32 cellGcmMapMainMemory(u64 ea, u32 size, mem32_t offset);
+s32 cellGcmReserveIoMapSize(u32 size);
+s32 cellGcmUnmapEaIoAddress(u64 ea);
+s32 cellGcmUnmapIoAddress(u64 io);
+s32 cellGcmUnreserveIoMapSize(u32 size);
diff --git a/rpcs3/Emu/SysCalls/Modules/sysPrxForUser.cpp b/rpcs3/Emu/SysCalls/Modules/sysPrxForUser.cpp
index d114db9933..2ab01ebac4 100644
--- a/rpcs3/Emu/SysCalls/Modules/sysPrxForUser.cpp
+++ b/rpcs3/Emu/SysCalls/Modules/sysPrxForUser.cpp
@@ -10,25 +10,12 @@
 #include "Emu/SysCalls/lv2/sys_spu.h"
 #include "Loader/ELF.h"
 #include "Emu/Cell/RawSPUThread.h"
+#include "sysPrxForUser.h"
 
 //void sysPrxForUser_init();
 //Module sysPrxForUser("sysPrxForUser", sysPrxForUser_init);
 Module *sysPrxForUser = nullptr;
 
-struct HeapInfo
-{
-	u32 heap_addr;
-	u32 align;
-	u32 size;
-
-	HeapInfo(u32 _heap_addr, u32 _align, u32 _size)
-		: heap_addr(_heap_addr)
-		, align(_align)
-		, size(_size)
-	{
-	}
-};
-
 int sys_heap_create_heap(const u32 heap_addr, const u32 align, const u32 size)
 {	
 	sysPrxForUser->Warning("sys_heap_create_heap(heap_addr=0x%x, align=0x%x, size=0x%x)", heap_addr, align, size);
@@ -177,6 +164,14 @@ int sys_raw_spu_image_load(int id, mem_ptr_t<sys_spu_image> img)
 	return CELL_OK;
 }
 
+s32 _sys_memset(u32 addr, s32 value, u32 size)
+{
+	sysPrxForUser->Log("_sys_memset(addr=0x%x, value=%d, size=%d)", addr, value, size);
+
+	memset(Memory + addr, value, size);
+	return CELL_OK;
+}
+
 void sysPrxForUser_init()
 {
 	sysPrxForUser->AddFunc(0x744680a2, sys_initialize_tls);
@@ -249,4 +244,6 @@ void sysPrxForUser_init()
 
 	sysPrxForUser->AddFunc(0x67f9fedb, sys_game_process_exitspawn2);
 	sysPrxForUser->AddFunc(0xfc52a7a9, sys_game_process_exitspawn);
+
+	sysPrxForUser->AddFunc(0x68b9b011, _sys_memset);
 }
diff --git a/rpcs3/Emu/SysCalls/Modules/sysPrxForUser.h b/rpcs3/Emu/SysCalls/Modules/sysPrxForUser.h
new file mode 100644
index 0000000000..d32efb69c5
--- /dev/null
+++ b/rpcs3/Emu/SysCalls/Modules/sysPrxForUser.h
@@ -0,0 +1,18 @@
+# pragma once
+
+struct HeapInfo
+{
+	u32 heap_addr;
+	u32 align;
+	u32 size;
+
+	HeapInfo(u32 _heap_addr, u32 _align, u32 _size)
+		: heap_addr(_heap_addr)
+		, align(_align)
+		, size(_size)
+	{
+	}
+};
+
+// SysCalls
+s32 _sys_memset(u32 addr, s32 value, u32 num);
diff --git a/rpcs3/emucore.vcxproj b/rpcs3/emucore.vcxproj
index 2ed228080d..8c856e1d45 100644
--- a/rpcs3/emucore.vcxproj
+++ b/rpcs3/emucore.vcxproj
@@ -346,6 +346,7 @@
     <ClInclude Include="Emu\SysCalls\Modules\cellDmux.h" />
     <ClInclude Include="Emu\SysCalls\Modules\cellFont.h" />
     <ClInclude Include="Emu\SysCalls\Modules\cellGame.h" />
+    <ClInclude Include="Emu\SysCalls\Modules\cellGcmSys.h" />
     <ClInclude Include="Emu\SysCalls\Modules\cellGifDec.h" />
     <ClInclude Include="Emu\SysCalls\Modules\cellJpgDec.h" />
     <ClInclude Include="Emu\SysCalls\Modules\cellNetCtl.h" />
@@ -367,6 +368,7 @@
     <ClInclude Include="Emu\SysCalls\Modules\libsynth2.h" />
     <ClInclude Include="Emu\SysCalls\Modules\sceNp.h" />
     <ClInclude Include="Emu\SysCalls\Modules\sceNpTrophy.h" />
+    <ClInclude Include="Emu\SysCalls\Modules\sysPrxForUser.h" />
     <ClInclude Include="Emu\SysCalls\Modules\sys_net.h" />
     <ClInclude Include="Emu\SysCalls\SC_FUNC.h" />
     <ClInclude Include="Emu\SysCalls\Static.h" />
diff --git a/rpcs3/emucore.vcxproj.filters b/rpcs3/emucore.vcxproj.filters
index 5a9604bec4..3b692b7c0a 100644
--- a/rpcs3/emucore.vcxproj.filters
+++ b/rpcs3/emucore.vcxproj.filters
@@ -1105,5 +1105,11 @@
     <ClInclude Include="Emu\SysCalls\LogBase.h">
       <Filter>Emu\SysCalls</Filter>
     </ClInclude>
+    <ClInclude Include="Emu\SysCalls\Modules\cellGcmSys.h">
+      <Filter>Emu\SysCalls\Modules</Filter>
+    </ClInclude>
+    <ClInclude Include="Emu\SysCalls\Modules\sysPrxForUser.h">
+      <Filter>Emu\SysCalls\Modules</Filter>
+    </ClInclude>
   </ItemGroup>
 </Project>