Optimize matrix scanning by removing variable shifts #14947
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AVR does not include a barrel shifter. Variable shifts compile into loops that carry the bits across multiple 8-bit registers. This small optimization increases the matrix scan rate on my keyboard from 598 to 628.
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Note that the per-key debouncers would also benefit from this optimization, but the impact is smaller. |
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Retargeted against |
tzarc
approved these changes
Oct 26, 2021
drashna
approved these changes
Oct 26, 2021
ptrxyz
pushed a commit
to ptrxyz/qmk_firmware
that referenced
this pull request
Apr 9, 2022
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Description
AVR does not include a barrel shifter. Variable shifts compile into
loops that carry the bits across multiple 8-bit registers.
This small optimization increases the matrix scan rate on my keyboard
from 598 to 628.
Types of Changes
Issues Fixed or Closed by This PR
Checklist