py/scheduler: Add "raise_exc" argument to mp_handle_pending.

Previous behaviour is when this argument is set to "true", in which case
the function will raise any pending exception.  Setting it to "false" will
cancel any pending exception.

2 files changed, 10 insertions, 6 deletions

diff --git a/py/runtime.h b/py/runtime.h
index b54b17b683..1c078ae81a 100644
--- a/py/runtime.h
+++ b/py/runtime.h
@@ -64,7 +64,7 @@ extern const byte mp_binary_op_method_name[];
 void mp_init(void);
 void mp_deinit(void);
 
-void mp_handle_pending(void);
+void mp_handle_pending(bool raise_exc);
 void mp_handle_pending_tail(mp_uint_t atomic_state);
 
 #if MICROPY_ENABLE_SCHEDULER
diff --git a/py/scheduler.c b/py/scheduler.c
index e7cbb524de..ff88be9583 100644
--- a/py/scheduler.c
+++ b/py/scheduler.c
@@ -44,7 +44,7 @@ static inline bool mp_sched_empty(void) {
 }
 
 // A variant of this is inlined in the VM at the pending exception check
-void mp_handle_pending(void) {
+void mp_handle_pending(bool raise_exc) {
     if (MP_STATE_VM(sched_state) == MP_SCHED_PENDING) {
         mp_uint_t atomic_state = MICROPY_BEGIN_ATOMIC_SECTION();
         mp_obj_t obj = MP_STATE_VM(mp_pending_exception);
@@ -53,8 +53,10 @@ void mp_handle_pending(void) {
             if (!mp_sched_num_pending()) {
                 MP_STATE_VM(sched_state) = MP_SCHED_IDLE;
             }
-            MICROPY_END_ATOMIC_SECTION(atomic_state);
-            nlr_raise(obj);
+            if (raise_exc) {
+                MICROPY_END_ATOMIC_SECTION(atomic_state);
+                nlr_raise(obj);
+            }
         }
         mp_handle_pending_tail(atomic_state);
     }
@@ -121,11 +123,13 @@ bool mp_sched_schedule(mp_obj_t function, mp_obj_t arg) {
 #else // MICROPY_ENABLE_SCHEDULER
 
 // A variant of this is inlined in the VM at the pending exception check
-void mp_handle_pending(void) {
+void mp_handle_pending(bool raise_exc) {
     if (MP_STATE_VM(mp_pending_exception) != MP_OBJ_NULL) {
         mp_obj_t obj = MP_STATE_VM(mp_pending_exception);
         MP_STATE_VM(mp_pending_exception) = MP_OBJ_NULL;
-        nlr_raise(obj);
+        if (raise_exc) {
+            nlr_raise(obj);
+        }
     }
 }