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filter_fir.cpp 1.7KB

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  1. /* Audio Library for Teensy 3.X
  2. * Copyright (c) 2014, Pete (El Supremo)
  3. *
  4. * Permission is hereby granted, free of charge, to any person obtaining a copy
  5. * of this software and associated documentation files (the "Software"), to deal
  6. * in the Software without restriction, including without limitation the rights
  7. * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  8. * copies of the Software, and to permit persons to whom the Software is
  9. * furnished to do so, subject to the following conditions:
  10. *
  11. * The above copyright notice and this permission notice shall be included in
  12. * all copies or substantial portions of the Software.
  13. *
  14. * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  15. * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  16. * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  17. * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  18. * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  19. * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  20. * THE SOFTWARE.
  21. */
  22. #include "filter_fir.h"
  23. void AudioFilterFIR::update(void)
  24. {
  25. audio_block_t *block, *b_new;
  26. block = receiveReadOnly();
  27. if (!block) return;
  28. // If there's no coefficient table, give up.
  29. if (coeff_p == NULL) {
  30. release(block);
  31. return;
  32. }
  33. // do passthru
  34. if (coeff_p == FIR_PASSTHRU) {
  35. // Just passthrough
  36. transmit(block);
  37. release(block);
  38. return;
  39. }
  40. // get a block for the FIR output
  41. b_new = allocate();
  42. if (b_new) {
  43. arm_fir_fast_q15(&fir_inst, (q15_t *)block->data,
  44. (q15_t *)b_new->data, AUDIO_BLOCK_SAMPLES);
  45. transmit(b_new); // send the FIR output
  46. release(b_new);
  47. }
  48. release(block);
  49. }