change sine implementation to deku65i version

[runger1101001]

We have already discussed it - this is now the PR for the sine optimisation.

It includes the following changes:

• introduce a new _sincos() function which computes sin and cos at the same time
  • based on this significant further optimisation is possible for users that want to implement it
  • for example, STM32 CORDIC can return both sin and cos in about 25 clock cycles...
• default implementation just calls _sin() and _cos() internally
• code that used both sine and cosine of the same value has been updated to use the new function

• default implementation of the _sin() function has been changed to the "deku65i" version
  • this uses a 65 entry LUT of 16bit values, and 8bits of fractional interpolation between neighbouring values
  • it uses the full precision of the 16bit values (rather than 10000x)
  • it can operate on any input angle (no need to normalize)
  • it is faster than the original version (by about 20% for just sine, or about 4.5x faster if you include normalizeAngle)
  • it is more precise than the original version (RMS precision compared to stdlib for new version 0.0000648 compared to 0.00161161 for original. That's in the range -PI,PI for 3217 steps of 1/1024 in size)
• remove normalizeAngle before calling sin/cos, since it isn't needed any more

Many details can be found in this thread in the forums, if one has the patience to follow it: https://community.simplefoc.com/t/embedded-world-2023-stm32-cordic-co-processor/3107

Tested on SAMD21, where it seems to give 5-10% overall performance boost to my main loop (velocity mode, sine-commutation, no current sense).

[askuric]

Nice!
I'm in and I'm looking forward to testing it.

[runger1101001]

Perfect, so I will merge it, and I'll also ask in the forum thread if people want to test the dev branch on their setups...