diff --git a/Source/inv.cpp b/Source/inv.cpp
index dc7a2cc6f..e6f2c98f0 100644
--- a/Source/inv.cpp
+++ b/Source/inv.cpp
@@ -114,35 +114,60 @@ void __cdecl InitInv()
 
 void __fastcall InvDrawSlotBack(int X, int Y, int W, int H)
 {
-	unsigned char *v4; // edi
-	int v5;            // edx
-	int v6;            // ecx
-	unsigned char v7;  // al
-	unsigned char v8;  // al
-
-	v4 = (unsigned char *)gpBuffer + screen_y_times_768[Y] + X;
-	v5 = (unsigned short)H;
-	do {
-		v6 = (unsigned short)W;
-		do {
-			v7 = *v4;
-			if (*v4 < 0xB0u)
-				goto LABEL_9;
-			if (v7 > 0xBFu) {
-				if (v7 < 0xF0u)
-					goto LABEL_9;
-				v8 = v7 - 80;
-			} else {
-				v8 = v7 - 16;
+	BYTE *dst;
+
+	/// ASSERT: assert(gpBuffer);
+
+	dst = &gpBuffer[X + screen_y_times_768[Y]];
+
+#if (_MSC_VER >= 800) && (_MSC_VER <= 1200)
+	__asm {
+		mov		edi, dst
+		xor		edx, edx
+		xor		ebx, ebx
+		mov		dx, word ptr H
+		mov		bx, word ptr W
+	label1:
+		mov		ecx, ebx
+	label2:
+		mov		al, [edi]
+		cmp		al, PAL16_BLUE
+		jb		label5
+		cmp		al, PAL16_BLUE + 15
+		ja		label3
+		sub		al, PAL16_BLUE - PAL16_BEIGE
+		jmp		label4
+	label3:
+		cmp		al, PAL16_GRAY
+		jb		label5
+		sub		al, PAL16_GRAY - PAL16_BEIGE
+	label4:
+		mov		[edi], al
+	label5:
+		inc		edi
+		loop	label2
+		sub		edi, 768
+		sub		edi, ebx
+		dec		edx
+		jnz		label1
+	}
+#else
+	int wdt, hgt;
+	BYTE pix;
+
+	for(hgt = H; hgt; hgt--, dst -= 768 + W) {
+		for(wdt = W; wdt; wdt--) {
+			pix = *dst;
+			if(pix >= PAL16_BLUE) {
+				if(pix <= PAL16_BLUE + 15)
+					pix -= PAL16_BLUE - PAL16_BEIGE;
+				else if(pix >= PAL16_GRAY)
+					pix -= PAL16_GRAY - PAL16_BEIGE;
 			}
-			*v4 = v8;
-		LABEL_9:
-			++v4;
-			--v6;
-		} while (v6);
-		v4 = &v4[-(unsigned short)W - 768];
-		--v5;
-	} while (v5);
+			*dst++ = pix;
+		}
+	}
+#endif
 }
 
 void __cdecl DrawInv()