Save code space by packing rgbw values into C union #7209
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It's more efficient passing one register-sized structure than 4 arguments or 4 pointers; working on intermediate values of 'int' size is also more efficient in code size! On raspberry pi pico w, this increased free flash space by +104 bytes. It also increased the speed of my testing animation very slightly, from 187fps to 189fps when run 'unthrottled'
brentru
reviewed
Nov 14, 2022
.. saves 20 bytes on proxlight trinkey
brentru
approved these changes
Nov 15, 2022
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It's more efficient passing one register-sized structure than 4 arguments or 4 pointers; working on intermediate values of 'int' size is also more efficient in code size!
On raspberry pi pico w, this increased free flash space by +104 bytes. It also increased the speed of my testing animation very slightly, from 187fps to 189fps when run 'unthrottled'
Interestingly the code savings on BOARD=adafruit_neokey_trinkey_m0 is smaller, just 28 bytes. The difference is probably because samd21 boards were already optimized for space ("-Os" optimization) However, there is still a savings.