more efficient

teensy4/usb.c

 			completestatus &= endpointN_notify_mask;
 #if 1
 			if (completestatus) {
-				int s;
 
 				// transmit:
-				s = 0;
 				uint32_t tx = completestatus >> 16;
-				while(tx) {
+				while (tx) {
 					int p=__builtin_ctz(tx);
-					if (p==0) {
-						run_callbacks(endpoint_queue_head + s * 2 + 1);
-						p = 1;
-					}
-					tx >>= p;
-					s += p;
-				};
+					run_callbacks(endpoint_queue_head + p * 2 + 1);
+					tx &= ~(1<<p);
+				}
 
 				// receive:
-				s = 0;
 				uint32_t rx = completestatus & 0xffff;
 				while(rx) {
 					int p=__builtin_ctz(rx);
-					if (p==0) {
-						run_callbacks(endpoint_queue_head + s * 2);
-						p = 1;
-					}
-					rx >>= p;
-					s += p;
+					run_callbacks(endpoint_queue_head + p * 2);
+					rx &= ~(1<<p);
 				};
 			}
 #else