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Remove overflow check for unsigned diffs

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Calculating diffs with *unsigned* integers will always produce the
correct result, as long as the diff is less than the type max.

For example, suppose we read 254 and 2 for an 8 bit value:

    2 - 254 = 4

Using this property, simplify diffs on time_get() comparisons.

Signed-off-by: Tim Crawford <tcrawford@system76.com>
This commit is contained in:
Tim Crawford
2021-08-15 21:22:01 -06:00
committed by Jeremy Soller
parent e00686a661
commit f55e493001
3 changed files with 6 additions and 18 deletions
Download Patch File Download Diff File Expand all files Collapse all files

4
src/board/system76/common/main.c
View File

@@ -122,7 +122,7 @@ void main(void) {
if (main_cycle == 0) {
uint32_t time = time_get();
// Only run the following once per interval
if (last_time_fan > time || (time - last_time_fan) >= fan_interval) {
if ((time - last_time_fan) >= fan_interval) {
last_time_fan = time;
// Update fan speeds
@@ -130,7 +130,7 @@ void main(void) {
}
// Only run the following once per interval
if (last_time_battery > time || (time - last_time_battery) >= battery_interval) {
if ((time - last_time_battery) >= battery_interval) {
last_time_battery = time;
// Updates battery status

2
src/board/system76/common/parallel.c
View File

@@ -34,7 +34,7 @@ bool parallel_debug = false;
static bool parallel_wait_peripheral(uint8_t mask, uint8_t value) {
uint32_t start = time_get();
while (time_get() < start + PARALLEL_TIMEOUT) {
while ((time_get() - start) < PARALLEL_TIMEOUT) {
if ((KSOHGDMRR & mask) == value) {
return true;
}

18
src/board/system76/common/power.c
View File

@@ -618,11 +618,7 @@ void power_event(void) {
#if EC_ESPI
if (!gpio_get(&CPU_C10_GATE_N)) {
// Modern suspend, flashing green light
if (
(time < last_time) // overflow
||
(time >= (last_time + 1000)) // timeout
) {
if ((time - last_time) >= 1000) {
gpio_set(&LED_PWR, !gpio_get(&LED_PWR));
last_time = time;
}
@@ -636,11 +632,7 @@ void power_event(void) {
}
} else if (power_state == POWER_STATE_S3 || power_state == POWER_STATE_DS3) {
// Suspended, flashing green light
if (
(time < last_time) // overflow
||
(time >= (last_time + 1000)) // timeout
) {
if ((time - last_time) >= 1000) {
gpio_set(&LED_PWR, !gpio_get(&LED_PWR));
last_time = time;
}
@@ -652,11 +644,7 @@ void power_event(void) {
} else {
// CPU off and AC adapter unplugged, flashing orange light
gpio_set(&LED_PWR, false);
if (
(time < last_time) // overflow
||
(time >= (last_time + 1000)) // timeout
) {
if ((time - last_time) >= 1000) {
gpio_set(&LED_ACIN, !gpio_get(&LED_ACIN));
last_time = time;
}