fm_op_kernel.h

/*
 * Copyright 2012 Google Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
 
#pragma once
 
#include "stdint.h"
 
struct FmOpParams {
    int32_t level_in; // value to be computed (from level to gain[0])
    int32_t gain_out; // computed value (gain[1] to gain[0])
    int32_t freq;
    int32_t phase;
};
 
class FmOpKernel {
public:
    // gain1 and gain2 represent linear step: gain for sample i is
    // gain1 + (1 + i) / 64 * (gain2 - gain1)
 
    // This is the basic FM operator. No feedback.
    static void compute(int32_t* output, int n, const int32_t* input, int32_t phase0, int32_t freq, int32_t gain1,
                        int32_t gain2, int32_t dgain, bool add, bool neon);
 
    // This is a sine generator, no feedback.
    static void compute_pure(int32_t* output, int n, int32_t phase0, int32_t freq, int32_t gain1, int32_t gain2,
                             int32_t dgain, bool add, bool neon);
 
    // One op with feedback, no add.
    static void compute_fb(int32_t* output, int n, int32_t phase0, int32_t freq, int32_t gain1, int32_t gain2,
                           int32_t dgain, int32_t* fb_buf, int fb_gain, bool add);
};