kc3-lang/kc3/math/sin.c

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• Hash : 7e01caf7
  Author : Thomas de Grivel
  Date : 2023-05-25T17:38:26
  

  math

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• math/sin.c

• /* c3
   * Copyright 2022,2023 kmx.io <contact@kmx.io>
   *
   * Permission is hereby granted to use this software granted the above
   * copyright notice and this permission paragraph are included in all
   * copies and substantial portions of this software.
   *
   * THIS SOFTWARE IS PROVIDED "AS-IS" WITHOUT ANY GUARANTEE OF
   * PURPOSE AND PERFORMANCE. IN NO EVENT WHATSOEVER SHALL THE
   * AUTHOR BE CONSIDERED LIABLE FOR THE USE AND PERFORMANCE OF
   * THIS SOFTWARE.
   */
  #include "sin.h"
  
  s8 sin_u8 (u8 x)
  {
    s16 i;
    u8 n;
    u8 side_bits;
    s8 y;
    side_bits = (sizeof(u8) * 8 - 3);
    n = (1 << side_bits) - 1;
    switch (x >> side_bits) {
    case 0:
      i = x & n;
      y = i * S8_MAX / n * S8_MAX / sqrt(n * n + i * i / n / n) / S8_MAX;
      return y;
    case 1:
      return 1;
    case 2:
      return 2;
    case 3:
      return 3;
    case 4:
      return 4;
    case 5:
      return 5;
    case 6:
      return 6;
    case 7:
      return 7;
    }
    assert(! "sin_u8: error");
    errx(1, "sin_u8");
    return 0;
  }
  

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