fm_core.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 "fm_op_kernel.h"
#include <array>
 
#define div_n(base, inv_n) ((int)((((int64_t)(base)) * (int64_t)(inv_n)) >> 30))
 
// TRICKY: neon_fm_kernel claims (n%12)==8 not allowed.
// make it 132 to allow 128 output with 4 byte padding
const static int DX_MAX_N = 132;
 
class FmOperatorInfo {
public:
    int in;
    int out;
};
 
// operator should be considered inaudible when gain_out is below this
const int kGainLevelThresh = 1120;
 
enum FmOperatorFlags {
    OUT_BUS_ONE = 1 << 0,
    OUT_BUS_TWO = 1 << 1,
    OUT_BUS_ADD = 1 << 2,
    IN_BUS_ONE = 1 << 4,
    IN_BUS_TWO = 1 << 5,
    FB_IN = 1 << 6,
    FB_OUT = 1 << 7
};
 
class FmAlgorithm {
public:
    int ops[6];
};
 
class FmCore {
public:
    virtual ~FmCore() {};
    static void dump();
    virtual void render(int32_t* output, int n, FmOpParams* params, int algorithm, int32_t* fb_buf,
                        int32_t feedback_gain);
    const static FmAlgorithm algorithms[32];
    bool neon = false;
 
protected:
    // NEON alignment is 16 bytes (128 bits)
    alignas(16) std::array<int32_t, DX_MAX_N> buf0_;
    alignas(16) std::array<int32_t, DX_MAX_N> buf1_;
 
    constexpr int32_t* buf(int bus) { return (bus == 0) ? buf0_.data() : buf1_.data(); }
};