Cleanup and optimization of the internal serial retrieval routines.

Renamed ATTR_NOINLINE to ATTR_NO_INLINE to fit with the rest of the library function attribute names.

LUFA/Common/FunctionAttributes.h

@@ -87,7 +87,7 @@
 			/** Prevents the compiler from considering a specified function for inlining. When applied, the given
 			 *  function will not be inlined under any circumstances.
 			 */
-			#define ATTR_NOINLINE               __attribute__ ((noinline))
+			#define ATTR_NO_INLINE              __attribute__ ((noinline))
 
 			/** Forces the compiler to inline the specified function. When applied, the given function will be
 			 *  inlined under all circumstances.

LUFA/Drivers/USB/LowLevel/DevChapter9.c

@@ -227,6 +227,12 @@ void USB_Device_GetConfiguration(void)
 }
 
 #if !defined(NO_INTERNAL_SERIAL) && (defined(USB_SERIES_6_AVR) || defined(USB_SERIES_7_AVR))
+static char USB_Device_NibbleToASCII(uint8_t Nibble)
+{
+	Nibble = ((Nibble & 0x0F) + '0');
+	return (Nibble > '9') ? (Nibble + ('A' - '9' - 1)) : Nibble;
+}
+
 static void USB_Device_GetInternalSerialDescriptor(void)
 {
 	struct
@@ -235,9 +241,6 @@ static void USB_Device_GetInternalSerialDescriptor(void)
 		int16_t                 UnicodeString[20];
 	} SignatureDescriptor;
 
-	uint8_t SigReadAddress  = 0x0E;
-	bool    OddNibbleRead   = false;
-
 	#if defined(USE_NONSTANDARD_DESCRIPTOR_NAMES)
 		SignatureDescriptor.Header.Size            = sizeof(SignatureDescriptor);
 		SignatureDescriptor.Header.Type            = DTYPE_String;
@@ -246,28 +249,19 @@ static void USB_Device_GetInternalSerialDescriptor(void)
 		SignatureDescriptor.Header.bDescriptorType = DTYPE_String;
 	#endif
 
+	uint8_t  SigReadAddress     = 0x0E;
+
 	for (uint8_t SerialCharNum = 0; SerialCharNum < 20; SerialCharNum++)
 	{
 		uint8_t SerialByte = boot_signature_byte_get(SigReadAddress);
 		
-		if (OddNibbleRead)
+		if (SerialCharNum & 0x01)
 		{
 			SerialByte >>= 4;
 			SigReadAddress++;
 		}
-		else
-		{
-			SerialByte &= 0x0F;
-		}
-		
-		OddNibbleRead = !(OddNibbleRead);
-
-		if (SerialByte < 0x0A)
-		  SerialByte += '0';
-		else
-		  SerialByte += ('A' - 0x0A);
 		
-		SignatureDescriptor.UnicodeString[SerialCharNum] = SerialByte;
+		SignatureDescriptor.UnicodeString[SerialCharNum] = USB_Device_NibbleToASCII(SerialByte);
 	}
 	
 	Endpoint_ClearSETUP();

LUFA/Drivers/USB/LowLevel/DevChapter9.h

@@ -124,6 +124,7 @@
 				static void USB_Device_ClearSetFeature(void);
 				
 				#if !defined(NO_INTERNAL_SERIAL) && (defined(USB_SERIES_6_AVR) || defined(USB_SERIES_7_AVR))
+					static char USB_Device_NibbleToASCII(uint8_t Nibble) ATTR_ALWAYS_INLINE;
 					static void USB_Device_GetInternalSerialDescriptor(void);
 				#endif				
 			#endif