simplelfo.hpp

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#pragma once
/*
    BSD 3-Clause License
 
    Copyright (c) 2018, KORG INC.
    All rights reserved.
 
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    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
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//*/
 
#include "fixed_math.h"
#include "int_math.h"
#include "float_math.h"
 
namespace dsp {    
 
  struct SimpleLFO {
    
    /*===========================================================================*/
    /* Types and Data Structures.                                                */
    /*===========================================================================*/
      
    /*===========================================================================*/
    /* Constructor / Destructor.                                                 */
    /*===========================================================================*/
 
    SimpleLFO(void) :
      phi0(0x80000000), w0(0)
    { }
      
    /*===========================================================================*/
    /* Public Methods.                                                           */
    /*===========================================================================*/
 
    inline __attribute__((optimize("Ofast"),always_inline))
    void cycle(void)
    {
      phi0 += w0;
    }
 
    inline __attribute__((optimize("Ofast"),always_inline))
    void reset(void) 
    {
      phi0 = 0x80000000;
    }
 
    inline __attribute__((optimize("Ofast"),always_inline))
    void setF0(const float f0, const float fsrecip) 
    {
      w0 = f32_to_q31(2.f * f0 * fsrecip);
    }
 
    inline __attribute__((optimize("Ofast"),always_inline))
    void setW0(const float w) 
    {
      w0 = f32_to_q31(2.f * w);
    }
    
    // --- Sinusoids --------------
 
    inline __attribute__((optimize("Ofast"),always_inline))
    float sine_bi(void) 
    {
      const float phif = q31_to_f32(phi0);
      return 4 * phif * (si_fabsf(phif) - 1.f);
    }          
 
    inline __attribute__((optimize("Ofast"),always_inline))
    float sine_uni(void) 
    {
      const float phif = q31_to_f32(phi0);
      return 0.5f + 2 * phif * (si_fabsf(phif) - 1.f);
    }          
 
    inline __attribute__((optimize("Ofast"),always_inline))
    float sine_bi_off(const float offset) 
    {
      const float phi = q31_to_f32(phi0 + f32_to_q31(2*offset));
      return 4 * phi * (si_fabsf(phi) - 1.f);
    }          
 
    inline __attribute__((optimize("Ofast"),always_inline))
    float sine_uni_off(const float offset) 
    {
      const float phi = q31_to_f32(phi0 + f32_to_q31(2*offset));
      return 0.5f + 2 * phi * (si_fabsf(phi) - 1.f);
    }          
 
    // --- Triangles --------------
    inline __attribute__((optimize("Ofast"),always_inline))
    float triangle_bi(void) 
    {
      return q31_to_f32(qsub(q31abs(phi0),0x40000000)<<1);
    }          
 
    inline __attribute__((optimize("Ofast"),always_inline))
    float triangle_uni(void) 
    {
      return si_fabsf(q31_to_f32(phi0));
    }          
 
    inline __attribute__((optimize("Ofast"),always_inline))
    float triangle_bi_off(const float offset) 
    {
      const q31_t phi = phi0 + f32_to_q31(2*offset);
      return q31_to_f32(qsub(q31abs(phi),0x40000000)<<1);
    }          
 
    inline __attribute__((optimize("Ofast"),always_inline))
    float triangle_uni_off(const float offset) 
    {
      const float phi = q31_to_f32(phi0 + f32_to_q31(2*offset));
      return si_fabsf(phi); 
    }
      
    // --- Saws --------------
    inline __attribute__((optimize("Ofast"),always_inline))
    float saw_bi(void) 
    {
      return q31_to_f32(phi0);
    }          
 
    inline __attribute__((optimize("Ofast"),always_inline))
    float saw_uni(void) 
    {
      return q31_to_f32(qadd((phi0>>1),0x40000000));
    }          
 
    inline __attribute__((optimize("Ofast"),always_inline))
    float saw_bi_off(const float offset) 
    {
      const q31_t phi = phi0 + (f32_to_q31(offset)<<1);
      return q31_to_f32(phi);
    }          
 
    inline __attribute__((optimize("Ofast"),always_inline))
    float saw_uni_off(const float offset) 
    {
      q31_t phi = phi0 + (f32_to_q31(offset)<<1);        
      return 0.5f * phi + 0.5f;
      phi >>= 1;
      return q31_to_f32(qadd(phi,0x40000000));
    }
      
    // --- Squares --------------
    inline __attribute__((optimize("Ofast"),always_inline))
    float square_bi(void) 
    {
      return (phi0 < 0) ? -1.f : 1.f;
    }          
 
    inline __attribute__((optimize("Ofast"),always_inline))
    float square_uni(void) 
    {
      return (phi0 < 0) ? 0.f : 1.f;
    }          
 
    inline __attribute__((optimize("Ofast"),always_inline))
    float square_bi_off(const float offset) 
    {
      const q31_t phi = phi0 + (f32_to_q31(offset)<<1);
      return (phi < 0) ? -1.f : 1.f;
    }          
 
    inline __attribute__((optimize("Ofast"),always_inline))
    float square_uni_off(const float offset) 
    {
      const q31_t phi = phi0 + (f32_to_q31(offset)<<1);
      return (phi < 0) ? 0.f : 1.f;
    }
      
    /*===========================================================================*/
    /* Members Vars                                                              */
    /*===========================================================================*/
      
    q31_t phi0;
    q31_t w0;
      
  };
}