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| author | Kevin O'Connor <kevin@koconnor.net> | 2017-04-03 10:10:35 -0400 |
|---|---|---|
| committer | Kevin O'Connor <kevin@koconnor.net> | 2017-04-03 10:39:49 -0400 |
| commit | fff73c7735618923b865fc93b3187ff323f2a57e (patch) | |
| tree | d0f5fb0a376bf795b013b97181091dde58d6443a | |
| parent | e44678ceba9095637af477c3cc6e41c8724c01f4 (diff) | |
| download | kutter-fff73c7735618923b865fc93b3187ff323f2a57e.tar.gz kutter-fff73c7735618923b865fc93b3187ff323f2a57e.tar.xz kutter-fff73c7735618923b865fc93b3187ff323f2a57e.zip | |
avr: Invert diff in timer checks
Minor optimization on avr.
Signed-off-by: Kevin O'Connor <kevin@koconnor.net>
| -rw-r--r-- | src/avr/timer.c | 14 |
1 files changed, 6 insertions, 8 deletions
diff --git a/src/avr/timer.c b/src/avr/timer.c index 1c4d03a9..a0acac73 100644 --- a/src/avr/timer.c +++ b/src/avr/timer.c @@ -152,8 +152,8 @@ ISR(TIMER1_COMPA_vect) // Run the next software timer next = sched_timer_dispatch(); - int16_t diff = next - timer_get(); - if (likely(diff < 0)) { + int16_t diff = timer_get() - next; + if (likely(diff >= 0)) { // Another timer is pending - briefly allow irqs to fire irq_enable(); if (unlikely(TIFR1 & (1<<OCF1B))) @@ -163,7 +163,7 @@ ISR(TIMER1_COMPA_vect) continue; } - if (likely(diff > TIMER_MIN_TRY_TICKS)) + if (likely(diff <= -TIMER_MIN_TRY_TICKS)) // Schedule next timer normally goto done; @@ -173,8 +173,8 @@ ISR(TIMER1_COMPA_vect) if (unlikely(TIFR1 & (1<<OCF1B))) goto force_defer; irq_disable(); - diff = next - timer_get(); - } while (diff >= 0); + diff = timer_get() - next; + } while (diff < 0); } force_defer: @@ -182,15 +182,13 @@ force_defer: irq_disable(); uint16_t now = timer_get(); if ((int16_t)(next - now) < (int16_t)(-timer_from_us(1000))) - goto fail; + shutdown("Rescheduled timer in the past"); timer_repeat_set(now + TIMER_REPEAT_TICKS); next = now + TIMER_DEFER_REPEAT_TICKS; done: timer_set(next); return; -fail: - shutdown("Rescheduled timer in the past"); } // Periodic background task that temporarily boosts priority of |