diff options
| author | Keith Packard <keithp@keithp.com> | 2011-01-15 12:25:57 -0800 |
|---|---|---|
| committer | Keith Packard <keithp@keithp.com> | 2011-01-16 20:24:36 -0800 |
| commit | 2887fe7affc0706dbeb2f04df9a00a9b799903ed (patch) | |
| tree | a0f24870448c27f6fa708dadffb49a22db719a1f | |
| parent | 2681a17500913cbaf3966f09380bb1d6b59e3863 (diff) | |
altos: Optimize fetching of ADC data in flight code
This stores the address of the desired sample in a local variable and
then fetches through that. Saves quite a few instructions.
Signed-off-by: Keith Packard <keithp@keithp.com>
| -rw-r--r-- | src/ao_flight.c | 8 |
1 files changed, 5 insertions, 3 deletions
diff --git a/src/ao_flight.c b/src/ao_flight.c index 9eb9a014..637acd52 100644 --- a/src/ao_flight.c +++ b/src/ao_flight.c @@ -151,12 +151,14 @@ ao_flight(void) while (ao_flight_adc != ao_adc_head) { __pdata uint8_t ticks; __pdata int16_t ao_vel_change; + __xdata struct ao_adc *ao_adc; ao_flight_prev_tick = ao_flight_tick; /* Capture a sample */ - ao_raw_accel = ao_adc_ring[ao_flight_adc].accel; - ao_raw_pres = ao_adc_ring[ao_flight_adc].pres; - ao_flight_tick = ao_adc_ring[ao_flight_adc].tick; + ao_adc = &ao_adc_ring[ao_flight_adc]; + ao_flight_tick = ao_adc->tick; + ao_raw_accel = ao_adc->accel; + ao_raw_pres = ao_adc->pres; ao_flight_accel -= ao_flight_accel >> 4; ao_flight_accel += ao_raw_accel >> 4; |