shared-bindings: Prevent check_lock from being optimized away. (adafruit#240)

tannewt · dhalbert · commit 6467e3d40b02 · 2017-09-06T17:49:30.000-04:00
Fixes adafruit#229
diff --git a/shared-bindings/busio/I2C.c b/shared-bindings/busio/I2C.c
@@ -110,6 +110,7 @@ STATIC mp_obj_t busio_i2c_obj___exit__(size_t n_args, const mp_obj_t *args) {
 STATIC MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(busio_i2c___exit___obj, 4, 4, busio_i2c_obj___exit__);
 
 static void check_lock(busio_i2c_obj_t *self) {
+    asm("");
     if (!common_hal_busio_i2c_has_lock(self)) {
         mp_raise_RuntimeError("Function requires lock.");
     }
diff --git a/shared-bindings/busio/SPI.c b/shared-bindings/busio/SPI.c
@@ -126,6 +126,7 @@ STATIC mp_obj_t busio_spi_obj___exit__(size_t n_args, const mp_obj_t *args) {
 STATIC MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(busio_spi_obj___exit___obj, 4, 4, busio_spi_obj___exit__);
 
 static void check_lock(busio_spi_obj_t *self) {
+    asm("");
     if (!common_hal_busio_spi_has_lock(self)) {
         mp_raise_RuntimeError("Function requires lock");
     }

Original file line number	Diff line number	Diff line change
`@@ -110,6 +110,7 @@ STATIC mp_obj_t busio_i2c_obj___exit__(size_t n_args, const mp_obj_t *args) {`
`110`	`110`	`STATIC MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(busio_i2c___exit___obj, 4, 4, busio_i2c_obj___exit__);`
`111`	`111`
`112`	`112`	`static void check_lock(busio_i2c_obj_t *self) {`
	`113`	`+ asm("");`
`113`	`114`	`if (!common_hal_busio_i2c_has_lock(self)) {`
`114`	`115`	`mp_raise_RuntimeError("Function requires lock.");`
`115`	`116`	`}`
Original file line number	Diff line number	Diff line change
`@@ -126,6 +126,7 @@ STATIC mp_obj_t busio_spi_obj___exit__(size_t n_args, const mp_obj_t *args) {`
`126`	`126`	`STATIC MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(busio_spi_obj___exit___obj, 4, 4, busio_spi_obj___exit__);`
`127`	`127`
`128`	`128`	`static void check_lock(busio_spi_obj_t *self) {`
	`129`	`+ asm("");`
`129`	`130`	`if (!common_hal_busio_spi_has_lock(self)) {`
`130`	`131`	`mp_raise_RuntimeError("Function requires lock");`
`131`	`132`	`}`