From cfeb4a3bceef95268b4aad38eb245b18df15f24e Mon Sep 17 00:00:00 2001
From: "David A. Mellis" <d.mellis@arduino.cc>
Date: Fri, 12 Jan 2007 21:27:18 +0000
Subject: [PATCH] Fixed bug in Serial.available() causing it to return
 incorrect values when the head wrapped around.  Thanks to Don Cross.

---
 targets/arduino/wiring.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/targets/arduino/wiring.c b/targets/arduino/wiring.c
index 7b9123665..52bac34d4 100755
--- a/targets/arduino/wiring.c
+++ b/targets/arduino/wiring.c
@@ -291,7 +291,7 @@ void serialWrite(unsigned char c)
 
 int serialAvailable()
 {
-	return (rx_buffer_head - rx_buffer_tail) % RX_BUFFER_SIZE;
+	return (RX_BUFFER_SIZE + rx_buffer_head - rx_buffer_tail) % RX_BUFFER_SIZE;
 }
 
 int serialRead()