ARMmbed
/
mbed-os
mirror of https://github.com/ARMmbed/mbed-os.git
1
0
Fork 0
Code Issues Projects Releases Wiki Activity

equeue: avoid non-standard bit shifts 

Shifting negative numbers right is implementation-defined, and shifting
positive signed numbers left and exceeding positive range is undefined.

Take care to make sure we always shift unsigned values.
pull/11782/head
Kevin Bracey 2019-10-31 12:56:27 +02:00
parent 8637069b36
commit aad7d9183b
1 changed files with 7 additions and 7 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

14
events/source/equeue.c
View File

@ -36,14 +36,14 @@ static inline int equeue_tickdiff(unsigned a, unsigned b)
static inline int equeue_clampdiff(unsigned a, unsigned b)
{
int diff = equeue_tickdiff(a, b);
return ~(diff >> (8 * sizeof(int) -1)) & diff;
return diff > 0 ? diff : 0;
}
// Increment the unique id in an event, hiding the event from cancel
static inline void equeue_incid(equeue_t *q, struct equeue_event *e)
{
e->id += 1;
if ((e->id << q->npw2) == 0) {
if (((unsigned)e->id << q->npw2) == 0) {
e->id = 1;
}
}
@ -280,7 +280,7 @@ void equeue_enqueue(equeue_t *q, struct equeue_event *e, unsigned tick)
static int equeue_event_id(equeue_t *q, struct equeue_event *e)
{
// setup event and hash local id with buffer offset for unique id
return ((e->id << q->npw2) | ((unsigned char *)e - q->buffer));
return ((unsigned)e->id << q->npw2) | ((unsigned char *)e - q->buffer);
}
static struct equeue_event *equeue_unqueue_by_address(equeue_t *q, struct equeue_event *e)
@ -319,10 +319,10 @@ static struct equeue_event *equeue_unqueue_by_id(equeue_t *q, int id)
{
// decode event from unique id and check that the local id matches
struct equeue_event *e = (struct equeue_event *)
&q->buffer[id & ((1 << q->npw2) - 1)];
&q->buffer[id & ((1u << q->npw2) - 1u)];
equeue_mutex_lock(&q->queuelock);
if (e->id != id >> q->npw2) {
if (e->id != (unsigned)id >> q->npw2) {
equeue_mutex_unlock(&q->queuelock);
return 0;
}
@ -447,10 +447,10 @@ int equeue_timeleft(equeue_t *q, int id)
// decode event from unique id and check that the local id matches
struct equeue_event *e = (struct equeue_event *)
&q->buffer[id & ((1 << q->npw2) - 1)];
&q->buffer[id & ((1u << q->npw2) - 1u)];
equeue_mutex_lock(&q->queuelock);
if (e->id == id >> q->npw2) {
if (e->id == (unsigned)id >> q->npw2) {
ret = equeue_clampdiff(e->target, equeue_tick());
}
equeue_mutex_unlock(&q->queuelock);