+#define BIT(a,b) ((a) | ((b) << 1))
+#define STATE(old_a, old_b, new_a, new_b) (((BIT(old_a, old_b) << 2) | BIT(new_a, new_b)))
+
+#define port(q) AO_QUADRATURE_ ## q ## _PORT
+#define bita(q) AO_QUADRATURE_ ## q ## _A
+#define bitb(q) AO_QUADRATURE_ ## q ## _B
+#define pina(q) AO_QUADRATURE_ ## q ## _A ## _PIN
+#define pinb(q) AO_QUADRATURE_ ## q ## _B ## _PIN
+#define isr(q) ao_quadrature_isr_ ## q
+
+static inline uint16_t
+ao_quadrature_read(struct stm_gpio *gpio, uint8_t pin_a, uint8_t pin_b) {
+ uint16_t v = stm_gpio_get_all(gpio);
+
+ return ~((((v >> pin_a) & 1) | (((v >> pin_b) & 1) << 1))) & 3;
+}
+
+#define _ao_quadrature_get(q) ao_quadrature_read(port(q), bita(q), bitb(q))