Fix overflow in timestamp calculation (esp-rs#287)

bjoernQ · May 23, 2024 · b95b23c · b95b23c
1 parent 8a580cd
commit b95b23c
Showing 1 changed file with 3 additions and 1 deletion.
diff --git a/esp-wifi/src/timer/xtensa.rs b/esp-wifi/src/timer/xtensa.rs
@@ -41,7 +41,9 @@ pub fn get_systimer_count() -> u64 {
         overflow = TIMER_OVERFLOWS.load(Ordering::Relaxed);
     }
 
-    (((overflow as u64) << 32) + counter_after as u64) * 40_000_000 / 240_000_000
+    // We have to precompute the divider to avoid overflow when multiplying.
+    const DIVIDER: u64 = 240_000_000 / TICKS_PER_SECOND;
+    (((overflow as u64) << 32) + counter_after as u64) / DIVIDER
 }
 
 pub fn setup_timer(mut timer1: TimeBase) {