fx_api.h

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/*
    BSD 3-Clause License
 
    Copyright (c) 2018, KORG INC.
    All rights reserved.
 
    Redistribution and use in source and binary forms, with or without
    modification, are permitted provided that the following conditions are met:
 
    * Redistributions of source code must retain the above copyright notice, this
      list of conditions and the following disclaimer.
 
    * Redistributions in binary form must reproduce the above copyright notice,
      this list of conditions and the following disclaimer in the documentation
      and/or other materials provided with the distribution.
 
    * Neither the name of the copyright holder nor the names of its
      contributors may be used to endorse or promote products derived from
      this software without specific prior written permission.
 
    THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
    AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
    IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
    DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
    FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
    DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
    SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
    CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
    OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
    OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
//*/
 
#ifndef __fx_api_h
#define __fx_api_h
 
#include "float_math.h"
#include "int_math.h"
#include "fixed_math.h"
 
#ifdef __cplusplus
extern "C" {
#endif
 
#define __fast_inline static inline __attribute__((always_inline, optimize("Ofast")))  
  
  /*===========================================================================*/
  /* Runtime Environment                                                       */
  /*===========================================================================*/
 
  extern const uint32_t k_fx_api_platform;
  
  extern const uint32_t k_fx_api_version;
  
  uint32_t _fx_mcu_hash(void);
 
  __fast_inline uint32_t fx_mcu_hash(void) {
    return _fx_mcu_hash();
  }
 
  uint16_t _fx_get_bpm(void);
 
  __fast_inline uint16_t fx_get_bpm(void) {
    return _fx_get_bpm();
  }
 
  float _fx_get_bpmf(void);
 
  __fast_inline float fx_get_bpmf(void) {
    return _fx_get_bpmf();
  }
 
  /*===========================================================================*/
  /* Lookup tables                                                             */
  /*===========================================================================*/
  
#define k_wt_sine_size_exp     (7)
#define k_wt_sine_size         (1U<<k_wt_sine_size_exp)
#define k_wt_sine_u32shift     (24)
#define k_wt_sine_frrecip      (5.96046447753906e-008f) // 1/(1<<24)
#define k_wt_sine_mask         (k_wt_sine_size-1)
#define k_wt_sine_lut_size     (k_wt_sine_size+1)
  
  extern const float wt_sine_lut_f[k_wt_sine_lut_size];
 
  __fast_inline float fx_sinf(float x) {
    const float p = x - (uint32_t)x;
    
    // half period stored -- wrap around and invert
    const float x0f = 2.f * p * k_wt_sine_size;
    const uint32_t x0p = (uint32_t)x0f;
 
    const uint32_t x0 = x0p & k_wt_sine_mask;
    const uint32_t x1 = (x0 + 1) & k_wt_sine_mask;
    
    const float y0 = linintf(x0f - x0p, wt_sine_lut_f[x0], wt_sine_lut_f[x1]);
    return (x0p < k_wt_sine_size)?y0:-y0;
  }
  
  __fast_inline float fx_sinuf(uint32_t x) {
    (void)x;
    return 0.f;
  }
  
  __fast_inline float fx_cosf(float x) {
    return fx_sinf(x+0.25f);
  }
 
  __fast_inline float fx_cosuf(uint32_t x) {
    return fx_sinuf(x+((k_wt_sine_size>>2)<<k_wt_sine_u32shift));
  }
  
  /*===========================================================================*/
  /* Various function lookups                                                  */
  /*===========================================================================*/
  
#define k_log_size_exp         (8)
#define k_log_size             (1U<<k_log_size_exp)
#define k_log_mask             (k_log_size-1)
#define k_log_lut_size         (k_log_size+1)
  
  extern const float log_lut_f[k_log_lut_size];
 
  __fast_inline float fx_logf(float x) {
    const float idxf = x * k_log_size;
    const uint32_t idx = (uint32_t)idxf;
    const float y0 = log_lut_f[idx];
    const float y1 = log_lut_f[idx+1];
    return linintf(idxf - idx, y0, y1);
  }
 
#define k_tanpi_size_exp         (8)
#define k_tanpi_size             (1U<<k_tanpi_size_exp)
#define k_tanpi_mask             (k_tanpi_size-1)
#define k_tanpi_range_recip      (2.04081632653061f) // 1/0.49
#define k_tanpi_lut_size         (k_tanpi_size+1)
  
  extern const float tanpi_lut_f[k_log_lut_size];
  
  __fast_inline float fx_tanpif(float x) {
    const float idxf = x * k_tanpi_range_recip * k_tanpi_size;
    const uint32_t idx = (uint32_t)idxf;
    const float y0 = tanpi_lut_f[idx];
    const float y1 = tanpi_lut_f[idx+1];
    return linintf(idxf - idx, y0, y1);
  }
 
#define k_sqrtm2log_size_exp         (8)
#define k_sqrtm2log_size             (1U<<k_sqrtm2log_size_exp)
#define k_sqrtm2log_mask             (k_sqrtm2log_size-1)
#define k_sqrtm2log_base             (0.005f)
#define k_sqrtm2log_range_recip      (1.00502512562814f) // 1/0.995
#define k_sqrtm2log_lut_size         (k_sqrtm2log_size+1)
  
  extern const float sqrtm2log_lut_f[k_sqrtm2log_lut_size];
  
  __fast_inline float fx_sqrtm2logf(float x) {
    const float idxf = (x-k_sqrtm2log_base) * k_sqrtm2log_range_recip * k_sqrtm2log_size;
    const uint32_t idx = (uint32_t)idxf;
    const float y0 = sqrtm2log_lut_f[idx];
    const float y1 = sqrtm2log_lut_f[idx+1];
    return linintf(idxf - idx, y0, y1);
  }
 
#define k_pow2_size_exp         (8)
#define k_pow2_size             (1U<<k_pow2_size_exp)
#define k_pow2_scale            (85.3333333333333f) // 256 / 3
#define k_pow2_mask             (k_pow2_size-1)
#define k_pow2_lut_size         (k_pow2_size+1)
  
  extern const float pow2_lut_f[k_pow2_lut_size];
 
  __fast_inline float fx_pow2f(float x) {
    const float idxf = x * k_pow2_scale;
    const uint32_t idx = (uint32_t)idxf;
    const float y0 = pow2_lut_f[idx];
    const float y1 = pow2_lut_f[idx+1];
    return linintf(idxf - idx, y0, y1);
  }
  
  /*===========================================================================*/
  /* Clipping and Saturation                                                   */
  /*===========================================================================*/
  __fast_inline float fx_softclipf(const float c, float x)
  {
    x = clip1m1f(x);
    return x - c * (x*x*x);
  }
 
#define k_cubicsat_size_exp  (7)
#define k_cubicsat_size      (1U<<k_cubicsat_size_exp)
#define k_cubicsat_mask      (k_cubicsat_size-1)
#define k_cubicsat_lut_size  (k_cubicsat_size+1)
  
  extern const float cubicsat_lut_f[k_cubicsat_lut_size];
  
  __fast_inline float fx_sat_cubicf(float x) {
    const float xf = si_fabsf(clip1f(x)) * k_cubicsat_size;
    const uint32_t xi = (uint32_t)x;
    const float y0 = cubicsat_lut_f[xi];
    const float y1 = cubicsat_lut_f[xi+1];
    return si_copysignf(linintf(xf - xi, y0, y1), x);
  }
 
#define k_schetzen_size_exp  (7)
#define k_schetzen_size      (1U<<k_schetzen_size_exp)
#define k_schetzen_mask      (k_schetzen_size-1)
#define k_schetzen_lut_size  (k_schetzen_size+1)
  
  extern const float schetzen_lut_f[k_schetzen_lut_size];
  
  __fast_inline float fx_sat_schetzenf(float x) {
    const float xf = si_fabsf(clip1f(x)) * k_schetzen_size;
    const uint32_t xi = (uint32_t)x;
    const float y0 = schetzen_lut_f[xi];
    const float y1 = schetzen_lut_f[xi+1];
    return si_copysignf(linintf(xf - xi, y0, y1), x);
  }
 
#define k_bitres_size_exp    (7)
#define k_bitres_size        (1U<<k_bitres_size_exp)
#define k_bitres_mask        (k_bitres_size-1)
#define k_bitres_lut_size    (k_bitres_size+1)
  
  extern const float bitres_lut_f[k_bitres_lut_size];
  
  __fast_inline float fx_bitresf(float x) {
    const float xf = x * k_bitres_size;
    const uint32_t xi = (uint32_t)xf;
    const float y0 = bitres_lut_f[xi];
    const float y1 = bitres_lut_f[xi+1];
    return linintf(xf - xi, y0, y1);
  }
 
  /*===========================================================================*/
  /* Noise source                                                              */
  /*===========================================================================*/
 
  uint32_t _fx_rand(void);
 
  __fast_inline uint32_t fx_rand(void) {
    return _fx_rand();
  }
  
  float _fx_white(void);
 
  __fast_inline float fx_white(void) {
    return _fx_white();
  }
  
#ifdef __cplusplus
}
#endif 
 
 
#endif // __fx_api_h