analyze_rms.cpp 2.6KB

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  1. /* Audio Library for Teensy 3.X
  2. * Copyright (c) 2014, Paul Stoffregen, paul@pjrc.com
  3. *
  4. * Development of this audio library was funded by PJRC.COM, LLC by sales of
  5. * Teensy and Audio Adaptor boards. Please support PJRC's efforts to develop
  6. * open source software by purchasing Teensy or other PJRC products.
  7. *
  8. * Permission is hereby granted, free of charge, to any person obtaining a copy
  9. * of this software and associated documentation files (the "Software"), to deal
  10. * in the Software without restriction, including without limitation the rights
  11. * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  12. * copies of the Software, and to permit persons to whom the Software is
  13. * furnished to do so, subject to the following conditions:
  14. *
  15. * The above copyright notice, development funding notice, and this permission
  16. * notice shall be included in all copies or substantial portions of the Software.
  17. *
  18. * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  19. * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  20. * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  21. * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  22. * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  23. * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  24. * THE SOFTWARE.
  25. */
  26. #include <Arduino.h>
  27. #include "analyze_rms.h"
  28. #include "utility/dspinst.h"
  29. void AudioAnalyzeRMS::update(void)
  30. {
  31. audio_block_t *block = receiveReadOnly();
  32. if (!block) {
  33. count++;
  34. return;
  35. }
  36. #if defined(__ARM_ARCH_7EM__)
  37. uint32_t *p = (uint32_t *)(block->data);
  38. uint32_t *end = p + AUDIO_BLOCK_SAMPLES/2;
  39. int64_t sum = accum;
  40. do {
  41. uint32_t n1 = *p++;
  42. uint32_t n2 = *p++;
  43. uint32_t n3 = *p++;
  44. uint32_t n4 = *p++;
  45. sum = multiply_accumulate_16tx16t_add_16bx16b(sum, n1, n1);
  46. sum = multiply_accumulate_16tx16t_add_16bx16b(sum, n2, n2);
  47. sum = multiply_accumulate_16tx16t_add_16bx16b(sum, n3, n3);
  48. sum = multiply_accumulate_16tx16t_add_16bx16b(sum, n4, n4);
  49. } while (p < end);
  50. accum = sum;
  51. count++;
  52. #else
  53. int16_t *p = block->data;
  54. int16_t *end = p + AUDIO_BLOCK_SAMPLES;
  55. int64_t sum = accum;
  56. do {
  57. int32_t n = *p++;
  58. sum += n * n;
  59. } while (p < end);
  60. accum = sum;
  61. count++;
  62. #endif
  63. release(block);
  64. }
  65. float AudioAnalyzeRMS::read(void)
  66. {
  67. __disable_irq();
  68. int64_t sum = accum;
  69. accum = 0;
  70. uint32_t num = count;
  71. count = 0;
  72. __enable_irq();
  73. float meansq = sum / (num * AUDIO_BLOCK_SAMPLES);
  74. // TODO: shift down to 32 bits and use sqrt_uint32
  75. // but is that really any more efficient?
  76. return sqrtf(meansq) / 32767.0;
  77. }