Fix align32_size().

cwalther · cwalther · commit 7ca36d45a4ff · 2020-11-28T17:54:34.000+01:00
It not only caused crashes with requests larger than 64K (can happen with RGBMatrix), but also generated a lot longer code than necessary.
diff --git a/shared-module/usb_midi/__init__.c b/shared-module/usb_midi/__init__.c
@@ -40,9 +40,9 @@ supervisor_allocation* usb_midi_allocation;
 
 void usb_midi_init(void) {
     // TODO(tannewt): Make this dynamic.
-    uint16_t tuple_size = align32_size(sizeof(mp_obj_tuple_t) + sizeof(mp_obj_t*) * 2);
-    uint16_t portin_size = align32_size(sizeof(usb_midi_portin_obj_t));
-    uint16_t portout_size = align32_size(sizeof(usb_midi_portout_obj_t));
+    size_t tuple_size = align32_size(sizeof(mp_obj_tuple_t) + sizeof(mp_obj_t*) * 2);
+    size_t portin_size = align32_size(sizeof(usb_midi_portin_obj_t));
+    size_t portout_size = align32_size(sizeof(usb_midi_portout_obj_t));
 
     // For each embedded MIDI Jack in the descriptor we create a Port
     usb_midi_allocation = allocate_memory(tuple_size + portin_size + portout_size, false, false);
diff --git a/supervisor/memory.h b/supervisor/memory.h
@@ -64,11 +64,8 @@ supervisor_allocation* allocate_remaining_memory(void);
 // supervisor_move_memory().
 supervisor_allocation* allocate_memory(uint32_t length, bool high_address, bool movable);
 
-static inline uint16_t align32_size(uint16_t size) {
-    if (size % 4 != 0) {
-        return (size & 0xfffc) + 0x4;
-    }
-    return size;
+static inline size_t align32_size(size_t size) {
+    return (size + 3) & ~3;
 }
 
 size_t get_allocation_length(supervisor_allocation* allocation);
