From 82954f823bc83c193be8c4d63c4bb2928b471a22 Mon Sep 17 00:00:00 2001
From: Andrew Tridgell <tridge@samba.org>
Date: Thu, 16 Aug 2012 15:18:17 +1000
Subject: [PATCH] SITL: make abs() 16 bit in SITL

this will help us find abs() bugs in autotest
---
 libraries/Desktop/include/wiring.h    | 3 ++-
 libraries/Desktop/support/Arduino.cpp | 9 +++++++++
 2 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/libraries/Desktop/include/wiring.h b/libraries/Desktop/include/wiring.h
index 0b8710eef7..8cf2fd7023 100644
--- a/libraries/Desktop/include/wiring.h
+++ b/libraries/Desktop/include/wiring.h
@@ -74,7 +74,6 @@ extern "C"{
 
 #define min(a,b) ((a)<(b)?(a):(b))
 #define max(a,b) ((a)>(b)?(a):(b))
-#define abs(x) ((x)>0?(x):-(x))
 #define constrain(amt,low,high) ((amt)<(low)?(low):((amt)>(high)?(high):(amt)))
 //#define round(x)     ((x)>=0?(long)((x)+0.5):(long)((x)-0.5))
 #define radians(deg) ((deg)*DEG_TO_RAD)
@@ -124,6 +123,8 @@ uint8_t shiftIn(uint8_t dataPin, uint8_t clockPin, uint8_t bitOrder);
 void attachInterrupt(uint8_t, void (*)(void), int mode);
 void detachInterrupt(uint8_t);
 
+int abs(int v);
+
 #ifdef __cplusplus
 } // extern "C"
 #endif
diff --git a/libraries/Desktop/support/Arduino.cpp b/libraries/Desktop/support/Arduino.cpp
index f82cc37e7c..a0c6c8e017 100644
--- a/libraries/Desktop/support/Arduino.cpp
+++ b/libraries/Desktop/support/Arduino.cpp
@@ -208,3 +208,12 @@ void runInterrupt(uint8_t inum)
 		interrupt_table[inum].call();
 	}
 }
+
+// this version of abs() is here to ensure it is 16 bit
+// which allows us to find abs() bugs in SITL
+int abs(int v)
+{
+	int16_t v16 = (int16_t)v;
+	if (v16 >= 0) return v16;
+	return -v16;
+}