text: /*
   $License:
      Copyright (C) 2011-2012 InvenSense Corporation, All Rights Reserved.
      See included License.txt for License information.
   $
   */
  #ifndef INVENSENSE_INV_MATH_FUNC_H__
  #define INVENSENSE_INV_MATH_FUNC_H__
  
  #include "mltypes.h"
  
  #define GYRO_MAG_SQR_SHIFT 6
  #define NUM_ROTATION_MATRIX_ELEMENTS (9)
  #define ROT_MATRIX_SCALE_LONG  (1073741824L)
  #define ROT_MATRIX_SCALE_FLOAT (1073741824.0f)
  #define ROT_MATRIX_LONG_TO_FLOAT( longval ) \
      ((float) ((longval) / ROT_MATRIX_SCALE_FLOAT ))
  #define SIGNM(k)((int)(k)&1?-1:1)
  #define SIGNSET(x) ((x) ? -1 : +1)
  
  #define INV_TWO_POWER_NEG_30 9.313225746154785e-010f
  
  #ifdef __cplusplus
  extern "C" {
  #endif
  
       typedef struct {
          float state[4];
          float c[5];
          float input;
          float output;
      }   inv_biquad_filter_t;
  
      static inline float inv_q30_to_float(long q30)
      {
          return (float) q30 / ((float)(1L << 30));
      }
  
      static inline double inv_q30_to_double(long q30)
      {
          return (double) q30 / ((double)(1L << 30));
      }
  
      static inline float inv_q16_to_float(long q16)
      {
          return (float) q16 / (1L << 16);
      }
  
      static inline double inv_q16_to_double(long q16)
      {
          return (double) q16 / (1L << 16);
      }
  
  
  
  
      long inv_q29_mult(long a, long b);
      long inv_q30_mult(long a, long b);
  
      /* UMPL_ELIMINATE_64BIT Notes:
       * An alternate implementation using float instead of long long accudoublemulators
       * is provided for q29_mult and q30_mult.
       * When long long accumulators are used and an alternate implementation is not
       * available, we eliminate the entire function and header with a macro.
       */
  #ifndef UMPL_ELIMINATE_64BIT
      long inv_q30_div(long a, long b);
      long inv_q_shift_mult(long a, long b, int shift);
  #endif
  
      void inv_q_mult(const long *q1, const long *q2, long *qProd);
      void inv_q_add(long *q1, long *q2, long *qSum);
      void inv_q_normalize(long *q);
      void inv_q_invert(const long *q, long *qInverted);
      void inv_q_multf(const float *q1, const float *q2, float *qProd);
      void inv_q_addf(const float *q1, const float *q2, float *qSum);
      void inv_q_normalizef(float *q);
      void inv_q_norm4(float *q);
      void inv_q_invertf(const float *q, float *qInverted);
      void inv_quaternion_to_rotation(const long *quat, long *rot);
      unsigned char *inv_int32_to_big8(long x, unsigned char *big8);
      long inv_big8_to_int32(const unsigned char *big8);
      short inv_big8_to_int16(const unsigned char *big8);
      short inv_little8_to_int16(const unsigned char *little8);
      unsigned char *inv_int16_to_big8(short x, unsigned char *big8);
      float inv_matrix_det(float *p, int *n);
      void inv_matrix_det_inc(float *a, float *b, int *n, int x, int y);
      double inv_matrix_detd(double *p, int *n);
      void inv_matrix_det_incd(double *a, double *b, int *n, int x, int y);
      float inv_wrap_angle(float ang);
      float inv_angle_diff(float ang1, float ang2);
      void inv_quaternion_to_rotation_vector(const long *quat, long *rot);
      unsigned short inv_orientation_matrix_to_scalar(const signed char *mtx);
      void inv_convert_to_body(unsigned short orientation, const long *input, long *output);
      void inv_convert_to_chip(unsigned short orientation, const long *input, long *output);
      void inv_convert_to_body_with_scale(unsigned short orientation, long sensitivity, const long *input, long *output);
      void inv_q_rotate(const long *q, const long *in, long *out);
  	void inv_vector_normalize(long *vec, int length);
      uint32_t inv_checksum(const unsigned char *str, int len);
      float inv_compass_angle(const long *compass, const long *grav,
                              const long *quat);
      unsigned long inv_get_gyro_sum_of_sqr(const long *gyro);
  
  #ifdef EMPL
      float inv_sinf(float x);
      float inv_cosf(float x);
      /* eMPL timestamps are assumed to be in milliseconds. */
      static inline long inv_delta_time_ms(inv_time_t t1, inv_time_t t2)
      {
          return (long)((t1 - t2));
      }
  #else
      static inline long inv_delta_time_ms(inv_time_t t1, inv_time_t t2)
      {
          return (long)((t1 - t2) / 1000000L);
      }
  #endif
  
      double quaternion_to_rotation_angle(const long *quat);
      double inv_vector_norm(const float *x);
  
      void inv_init_biquad_filter(inv_biquad_filter_t *pFilter, float *pBiquadCoeff);
      float inv_biquad_filter_process(inv_biquad_filter_t *pFilter, float input);
      void inv_calc_state_to_match_output(inv_biquad_filter_t *pFilter, float input);
      void inv_get_cross_product_vec(float *cgcross, float compass[3], float grav[3]);
  
      void mlMatrixVectorMult(long matrix[9], const long vecIn[3], long *vecOut);
  
  #ifdef __cplusplus
  }
  #endif
  #endif // INVENSENSE_INV_MATH_FUNC_H__