analogWriteResolution() returns prior setting

teensy3/core_pins.h

 void pinMode(uint8_t pin, uint8_t mode);
 void init_pins(void);
 void analogWrite(uint8_t pin, int val);
-void analogWriteRes(uint32_t bits);
-static inline void analogWriteResolution(uint32_t bits) { analogWriteRes(bits); }
+uint32_t analogWriteRes(uint32_t bits);
+static inline uint32_t analogWriteResolution(uint32_t bits) { return analogWriteRes(bits); }
 void analogWriteFrequency(uint8_t pin, float frequency);
 void analogWriteDAC0(int val);
 void analogWriteDAC1(int val);

teensy3/pins_teensy.c

 }
 
 
-void analogWriteRes(uint32_t bits)
+uint32_t analogWriteRes(uint32_t bits)
 {
+	uint32_t prior_res;
 	if (bits < 1) {
 		bits = 1;
 	} else if (bits > 16) {
 		bits = 16;
 	}
+	prior_res = analog_write_res;
 	analog_write_res = bits;
+	return prior_res;
 }