desktop: added attachInterrupt() support

libraries/Desktop/support/Arduino.cpp

@@ -156,3 +156,28 @@ char *ltoa(long __val, char *__s, int __radix)
 	return __s;
 }
 
+#define ARRAY_LENGTH(x) (sizeof((x))/sizeof((x)[0]))
+
+static struct {
+	void (*call)(void);
+} interrupt_table[7];
+
+void attachInterrupt(uint8_t inum, void (*call)(void), int mode)
+{
+	if (inum >= ARRAY_LENGTH(interrupt_table)) {
+		fprintf(stderr, "Bad attachInterrupt to interrupt %u\n", inum);
+		exit(1);
+	}
+	interrupt_table[inum].call = call;
+}
+
+void runInterrupt(uint8_t inum)
+{
+	if (inum >= ARRAY_LENGTH(interrupt_table)) {
+		fprintf(stderr, "Bad runInterrupt to interrupt %u\n", inum);
+		exit(1);
+	}
+	if (interrupt_table[inum].call != NULL) {
+		interrupt_table[inum].call();
+	}
+}

libraries/Desktop/support/sitl_adc.cpp

@@ -86,6 +86,7 @@ void sitl_update_adc(float roll, float pitch, float yaw,
 		UDR2.set(sensor_map[i], adc[i]);
 	}
 
+	runInterrupt(6);
 
 	// set the airspeed sensor input
 	UDR2.set(7, airspeed_sensor(airspeed));

libraries/Desktop/support/util.h

@@ -6,3 +6,4 @@
 void set_nonblocking(int fd);
 double normalise(double v, double min, double max);
 double normalise180(double v);
+void runInterrupt(uint8_t inum);