Avoid using floating point in the heartbeat code #132
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toofishes
commented
Dec 10, 2020
| int rc=1; | ||
| if ((m_HsInterval != 0) && (sinceLastPulse > m_HsInterval)) { //HEARTBEAT_SUPERVISION is currently active and the Heartbeat interval has timed out | ||
| if (m_HsInterval != 0 && sinceLastPulse > (m_HsInterval * 1000)) { //HEARTBEAT_SUPERVISION is currently active and the Heartbeat interval has timed out |
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Definitely double check my work here- by not dividing by 1000 on line 2093, we can multiply the other side of our comparison by 1000 on line 2095 and the logic is equivalent.
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Prior work in 2015 in this repository (commit 1c8ae71 and 52f3151) had removed all uses of floating point, saving the flash memory needed for floating point software routines. More recently, floating point is used if HEARTBEAT_SUPERVISION is enabled. By making a few small changes and adjusting things to use integer math, we can save 600+ bytes of flash. This also removes the deprecated function `HsDeactivate` which isn't called from anywhere.
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thanks again for another great PR. Yes, the bloat-o-meter would be great. you can add it to the util directory |
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Prior work in 2015 in this repository (commit 1c8ae71 and 52f3151)
had removed all uses of floating point, saving the flash memory needed
for floating point software routines.
More recently, floating point is used if HEARTBEAT_SUPERVISION is
enabled. By making a few small changes and adjusting things to use
integer math, we can save 600+ bytes of flash.
This also removes the deprecated function
HsDeactivatewhich isn'tcalled from anywhere.
Before (with HEARTBEAT_SUPERVISION defined):
After (with HEARTBEAT_SUPERVISION defined):
Let me know if you want this script I used below- I can PR and include it in the repository! It is based off of https://github.com/torvalds/linux/blob/master/scripts/bloat-o-meter and tailored to work for platformio and C++ symbols. Here it is showing that several floating point functions were included before, and 608 bytes have been trimmed.