diff --git a/Source/automap.cpp b/Source/automap.cpp
index 335d4f630..881c8b454 100644
--- a/Source/automap.cpp
+++ b/Source/automap.cpp
@@ -70,7 +70,7 @@ void __cdecl InitAutomap()
 		++v1;
 	}
 	while ( v1 < 31 );
-	memset(automaptype, 0, 0x400u);
+	memset(automaptype, 0, sizeof(automaptype));
 	switch ( leveltype )
 	{
 		case DTYPE_CATHEDRAL:
@@ -103,7 +103,7 @@ void __cdecl InitAutomap()
 		automaptype[i] = v8;
 	}
 	mem_free_dbg(v7);
-	memset(automapview, 0, 0x640u);
+	memset(automapview, 0, sizeof(automapview));
 	v13 = 0;
 	do
 	{
diff --git a/Source/codec.cpp b/Source/codec.cpp
index 416b5c090..805fd365f 100644
--- a/Source/codec.cpp
+++ b/Source/codec.cpp
@@ -38,7 +38,7 @@ int __fastcall codec_decode(void *pbSrcDst, int size, char *pszPassword)
 			}
 			while ( v7 < 64 );
 			SHA1Calculate(0, v9, 0);
-			memset(dst, 0, 0x14u);
+			memset(dst, 0, sizeof(dst));
 			memcpy(v4, v9, 0x40u);
 			v4 += 64;
 			passworda -= 64;
@@ -46,7 +46,7 @@ int __fastcall codec_decode(void *pbSrcDst, int size, char *pszPassword)
 		while ( passworda );
 		v5 = v11;
 	}
-	memset(v9, 0, 0x80u);
+	memset(v9, 0, sizeof(v9));
 	if ( !v4[4] )
 	{
 		SHA1Result(0, dst);
@@ -55,7 +55,7 @@ int __fastcall codec_decode(void *pbSrcDst, int size, char *pszPassword)
 			v8 = v5 + (unsigned char)v4[5] - 64;
 			goto LABEL_14;
 		}
-		memset(dst, 0, 0x14u);
+		memset(dst, 0, sizeof(dst));
 	}
 	v8 = 0;
 LABEL_14:
@@ -108,8 +108,8 @@ void __fastcall codec_init_key(int unused, char *pszPassword)
 		++v7;
 	}
 	while ( v7 < 0x88 );
-	memset(v10, 0, 0x40u);
-	memset(dst, 0, 0x14u);
+	memset(v10, 0, sizeof(v10));
+	memset(dst, 0, sizeof(dst));
 	v8 = 0;
 	do
 	{
@@ -117,7 +117,7 @@ void __fastcall codec_init_key(int unused, char *pszPassword)
 		SHA1Calculate(v8++, &v9[72], 0);
 	}
 	while ( v8 < 3 );
-	memset(v9, 0, 0x88u);
+	memset(v9, 0, sizeof(v9));
 }
 // 4035DB: using guessed type char var_E0[72];
 // 4035DB: using guessed type char var_58[64];
@@ -166,7 +166,7 @@ void __fastcall codec_encode(void *pbSrcDst, int size, int size_64, char *pszPas
 				++v7;
 			}
 			while ( v7 < 64 );
-			memset(dst, 0, 0x14u);
+			memset(dst, 0, sizeof(dst));
 			memcpy(v4, v9, 0x40u);
 			v4 += 64;
 			v12 -= v6;
@@ -174,7 +174,7 @@ void __fastcall codec_encode(void *pbSrcDst, int size, int size_64, char *pszPas
 		while ( v12 );
 		v5 = v6;
 	}
-	memset(v9, 0, 0x80u);
+	memset(v9, 0, sizeof(v9));
 	SHA1Result(0, v10);
 	v4[4] = 0;
 	*((_WORD *)v4 + 3) = 0;
diff --git a/Source/control.cpp b/Source/control.cpp
index 70046ac57..fbcf184ae 100644
--- a/Source/control.cpp
+++ b/Source/control.cpp
@@ -2956,7 +2956,7 @@ void __fastcall control_drop_gold(int vkey)
 		dropGoldValue = 0;
 		return;
 	}
-	memset(v6, 0, 6u);
+	memset(v6, 0, sizeof(v6));
 	_itoa(dropGoldValue, v6, 10);
 	if ( v1 != VK_RETURN )
 	{
diff --git a/Source/drlg_l3.cpp b/Source/drlg_l3.cpp
index 6abec8832..7a029919b 100644
--- a/Source/drlg_l3.cpp
+++ b/Source/drlg_l3.cpp
@@ -659,7 +659,7 @@ void __cdecl InitL3Dungeon()
 	int i; // edx
 	int j; // ecx
 
-	memset(dungeon, 0, 0x640u);
+	memset(dungeon, 0, sizeof(dungeon));
 
 	for(i = 0; i < 40; i++)
 	{
diff --git a/Source/drlg_l4.cpp b/Source/drlg_l4.cpp
index 8c646d782..5ab639be2 100644
--- a/Source/drlg_l4.cpp
+++ b/Source/drlg_l4.cpp
@@ -889,8 +889,8 @@ void __cdecl InitL4Dungeon()
 	signed int v1; // eax
 	signed int v2; // ecx
 
-	memset(dung, 0, 0x190u);
-	memset(L4dungeon, 0, 0x1900u);
+	memset(dung, 0, sizeof(dung));
+	memset(L4dungeon, 0, sizeof(L4dungeon));
 	v0 = 0;
 	do
 	{
diff --git a/Source/dx.cpp b/Source/dx.cpp
index fdd5e4d27..b9f046464 100644
--- a/Source/dx.cpp
+++ b/Source/dx.cpp
@@ -125,10 +125,10 @@ void __cdecl dx_create_back_buffer()
 		if ( v1 != DDERR_CANTLOCKSURFACE )
 			ErrDlg(IDD_DIALOG1, v1, "C:\\Src\\Diablo\\Source\\dx.cpp", 81);
 	}
-	memset(&v4, 0, 0x6Cu);
+	memset(&v4, 0, sizeof(v4));
 	v4.dwWidth = 768;
 	v4.lPitch = 768;
-	v4.dwSize = 108;
+	v4.dwSize = sizeof(v4);
 	v4.dwFlags = DDSD_PIXELFORMAT|DDSD_PITCH|DDSD_WIDTH|DDSD_HEIGHT|DDSD_CAPS;
 	v4.ddsCaps.dwCaps = DDSCAPS_SYSTEMMEMORY|DDSCAPS_OFFSCREENPLAIN;
 	v4.dwHeight = 656;
@@ -147,8 +147,8 @@ void __cdecl dx_create_primary_surface()
 	int v0; // eax
 	DDSURFACEDESC v1; // [esp+0h] [ebp-6Ch]
 
-	memset(&v1, 0, 0x6Cu);
-	v1.dwSize = 108;
+	memset(&v1, 0, sizeof(v1));
+	v1.dwSize = sizeof(v1);
 	v1.dwFlags = DDSD_CAPS;
 	v1.ddsCaps.dwCaps = DDSCAPS_PRIMARYSURFACE;
 	v0 = lpDDInterface->CreateSurface(&v1, &lpDDSPrimary, NULL);
@@ -198,7 +198,7 @@ void __cdecl lock_buf_priv()
 	{
 		if ( sgdwLockCount )
 			goto LABEL_9;
-		v2.dwSize = 108;
+		v2.dwSize = sizeof(v2);
 		v1 = lpDDSBackBuf->Lock(NULL, &v2, DDLOCK_WAIT, NULL);
 		if ( v1 )
 			DDErrMsg(v1, 235, "C:\\Src\\Diablo\\Source\\dx.cpp");
diff --git a/Source/gendung.cpp b/Source/gendung.cpp
index f43ad3754..a7c8e2811 100644
--- a/Source/gendung.cpp
+++ b/Source/gendung.cpp
@@ -78,11 +78,11 @@ void __cdecl FillSolidBlockTbls()
 	unsigned char v4; // bl
 	int size; // [esp+8h] [ebp-4h]
 
-	memset(nBlockTable, 0, 0x801u);
-	memset(nSolidTable, 0, 0x801u);
-	memset(nTransTable, 0, 0x801u);
-	memset(nMissileTable, 0, 0x801u);
-	memset(nTrapTable, 0, 0x801u);
+	memset(nBlockTable, 0, sizeof(nBlockTable));
+	memset(nSolidTable, 0, sizeof(nSolidTable));
+	memset(nTransTable, 0, sizeof(nTransTable));
+	memset(nMissileTable, 0, sizeof(nMissileTable));
+	memset(nTrapTable, 0, sizeof(nTrapTable));
 	if ( leveltype != DTYPE_TOWN )
 	{
 		switch ( leveltype )
@@ -674,8 +674,8 @@ void __cdecl SetDungeonMicros()
 
 void __cdecl DRLG_InitTrans()
 {
-	memset(dung_map, 0, 0x3100u);
-	memset(TransList, 0, 0x100u);
+	memset(dung_map, 0, sizeof(dung_map));
+	memset(TransList, 0, sizeof(TransList));
 	TransVal = 1;
 }
 // 5A5590: using guessed type char TransVal;
@@ -913,8 +913,8 @@ bool __fastcall DRLG_WillThemeRoomFit(int floor, int x, int y, int minSize, int
 		return 0;
 	if ( !SkipThemeRoom(x, y) )
 		return 0;
-	memset(xArray, 0, 0x50u);
-	memset(yArray, 0, 0x50u);
+	memset(xArray, 0, sizeof(xArray));
+	memset(yArray, 0, sizeof(yArray));
 	if ( maxSize > 0 )
 	{
 		v10 = 40 * v7;
@@ -1279,7 +1279,7 @@ void __fastcall DRLG_PlaceThemeRooms(int minSize, int maxSize, int floor, int fr
 	maxSize2 = maxSize;
 	minSize2 = minSize;
 	themeCount = 0;
-	memset(themeLoc, 0, 0x14u);
+	memset(themeLoc, 0, sizeof(*themeLoc));
 	do
 	{
 		x = 0;
diff --git a/Source/items.cpp b/Source/items.cpp
index 12fbc9009..2385f5e43 100644
--- a/Source/items.cpp
+++ b/Source/items.cpp
@@ -647,7 +647,7 @@ void __cdecl InitItemGFX()
 		++v0;
 	}
 	while ( v0 < 35 );
-	memset(UniqueItemFlag, 0, 0x200u);
+	memset(UniqueItemFlag, 0, sizeof(UniqueItemFlag));
 }
 
 bool __fastcall ItemPlace(int xp, int yp)
@@ -2914,7 +2914,7 @@ int __fastcall CheckUnique(int i, int lvl, int uper, bool recreate)
 	if ( random(28, 100) > uper )
 		return -1;
 	numu = 0;
-	memset(uok, 0, 0x80u);
+	memset(uok, 0, sizeof(uok));
 
 	if ( UniqueItemList[0].UIItemId == -1 )
 		return -1;
diff --git a/Source/lighting.cpp b/Source/lighting.cpp
index a9749e4c9..20f07eb7a 100644
--- a/Source/lighting.cpp
+++ b/Source/lighting.cpp
@@ -1373,11 +1373,11 @@ void __cdecl ToggleLighting()
 	lightflag ^= 1;
 	if ( lightflag )
 	{
-		memset(dTransVal, 0, 0x3100u);
+		memset(dTransVal, 0, sizeof(dTransVal));
 	}
 	else
 	{
-		memcpy(dTransVal, dTransVal2, 0x3100u);
+		memcpy(dTransVal, dTransVal2, sizeof(dTransVal));
 		for(i = 0; i < 4; i++)
 		{
 			if ( plr[i].plractive )
diff --git a/Source/objects.cpp b/Source/objects.cpp
index 3a1a6885b..64a2ca3df 100644
--- a/Source/objects.cpp
+++ b/Source/objects.cpp
@@ -375,7 +375,7 @@ void __cdecl InitObjectGFX()
 	unsigned char fileload[56]; // [esp+4h] [ebp-58h]
 	char filestr[32]; // [esp+3Ch] [ebp-20h]
 
-	memset(fileload, 0, 0x38u);
+	memset(fileload, 0, sizeof(fileload));
 	if ( AllObjects[0].oload != -1 )
 	{
 		v0 = AllObjects;
diff --git a/Source/pfile.cpp b/Source/pfile.cpp
index 04fea7a06..440163967 100644
--- a/Source/pfile.cpp
+++ b/Source/pfile.cpp
@@ -308,7 +308,7 @@ BOOL __stdcall pfile_ui_set_hero_infos(BOOL (__stdcall *ui_add_hero_info)(_uiher
 	LPCSTR lpSrcStr; // [esp+7C0h] [ebp-8h]
 	int save_num; // [esp+7C4h] [ebp-4h]
 
-	memset(hero_names, 0, 0x140u);
+	memset(hero_names, 0, sizeof(hero_names));
 	if ( (unsigned char)gbMaxPlayers > 1u )
 	{
 		lpSrcStr = 0;
diff --git a/Source/town.cpp b/Source/town.cpp
index 85f8fe269..0caa7da75 100644
--- a/Source/town.cpp
+++ b/Source/town.cpp
@@ -1639,13 +1639,13 @@ void __fastcall CreateTown(int entry)
 		ViewY = 68;
 	}
 	T_Pass3();
-	memset(dTransVal, 0, 0x3100u);
-	memset(dFlags, 0, 0x3100u);
-	memset(dPlayer, 0, 0x3100u);
-	memset(dMonster, 0, 0xC400u);
-	memset(dObject, 0, 0x3100u);
-	memset(dItem, 0, 0x3100u);
-	memset(dArch, 0, 0x3100u);
+	memset(dTransVal, 0, sizeof(dTransVal));
+	memset(dFlags, 0, sizeof(dFlags));
+	memset(dPlayer, 0, sizeof(dPlayer));
+	memset(dMonster, 0, sizeof(dMonster));
+	memset(dObject, 0, sizeof(dObject));
+	memset(dItem, 0, sizeof(dItem));
+	memset(dArch, 0, sizeof(dArch));
 	v2 = dPiece;
 	do
 	{