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instant rpm clearer truncation to 32 bits time

This commit is contained in:
Matthew Kennedy 2024-04-25 16:50:35 -07:00 committed by rusefillc
parent 61dc1116b9
commit 3127a1dcd2
1 changed files with 9 additions and 6 deletions
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15
firmware/controllers/trigger/instant_rpm_calculator.cpp
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@ -51,10 +51,15 @@ float InstantRpmCalculator::calculateInstantRpm(
TriggerWaveform const & triggerShape, TriggerFormDetails *triggerFormDetails,
uint32_t current_index, efitick_t nowNt) {
// It's OK to truncate from 64b to 32b, ARM with single precision FPU uses an expensive
// software function to convert 64b int -> float, while 32b int -> float is very cheap hardware conversion
// The difference is guaranteed to be short (it's 90 degrees of engine rotation!), so it won't overflow.
uint32_t nowNt32 = nowNt;
assertIsInBoundsWithResult(current_index, timeOfLastEvent, "calc timeOfLastEvent", 0);
// Record the time of this event so we can calculate RPM from it later
timeOfLastEvent[current_index] = nowNt;
timeOfLastEvent[current_index] = nowNt32;
// Determine where we currently are in the revolution
angle_t currentAngle = triggerFormDetails->eventAngles[current_index];
@ -74,10 +79,7 @@ float InstantRpmCalculator::calculateInstantRpm(
return prevInstantRpmValue;
}
// It's OK to truncate from 64b to 32b, ARM with single precision FPU uses an expensive
// software function to convert 64b int -> float, while 32b int -> float is very cheap hardware conversion
// The difference is guaranteed to be short (it's 90 degrees of engine rotation!), so it won't overflow.
uint32_t time = nowNt - time90ago;
uint32_t time = nowNt32 - time90ago;
angle_t angleDiff = currentAngle - prevIndexAngle;
// Wrap the angle in to the correct range (ie, could be -630 when we want +90)
@ -113,7 +115,8 @@ void InstantRpmCalculator::setLastEventTimeForInstantRpm(efitick_t nowNt) {
return;
}
spinningEvents[spinningEventIndex] = nowNt;
uint32_t nowNt32 = nowNt;
spinningEvents[spinningEventIndex] = nowNt32;
// If we are using only rising edges, we never write in to the odd-index slots that
// would be used by falling edges