mirror of
https://github.com/eried/portapack-mayhem.git
synced 2024-12-25 23:39:37 -05:00
133 lines
3.5 KiB
C++
133 lines
3.5 KiB
C++
/*
|
|
* Copyright (C) 2014 Jared Boone, ShareBrained Technology, Inc.
|
|
*
|
|
* This file is part of PortaPack.
|
|
*
|
|
* This program is free software; you can redistribute it and/or modify
|
|
* it under the terms of the GNU General Public License as published by
|
|
* the Free Software Foundation; either version 2, or (at your option)
|
|
* any later version.
|
|
*
|
|
* This program is distributed in the hope that it will be useful,
|
|
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
* GNU General Public License for more details.
|
|
*
|
|
* You should have received a copy of the GNU General Public License
|
|
* along with this program; see the file COPYING. If not, write to
|
|
* the Free Software Foundation, Inc., 51 Franklin Street,
|
|
* Boston, MA 02110-1301, USA.
|
|
*/
|
|
|
|
#include "utility.hpp"
|
|
|
|
#include <cstdint>
|
|
|
|
#if 0
|
|
uint32_t gcd(const uint32_t u, const uint32_t v) {
|
|
/* From http://en.wikipedia.org/wiki/Binary_GCD_algorithm */
|
|
|
|
if( u == v ) {
|
|
return u;
|
|
}
|
|
|
|
if( u == 0 ) {
|
|
return v;
|
|
}
|
|
|
|
if( v == 0 ) {
|
|
return u;
|
|
}
|
|
|
|
if( ~u & 1 ) {
|
|
if( v & 1 ) {
|
|
return gcd(u >> 1, v);
|
|
} else {
|
|
return gcd(u >> 1, v >> 1) << 1;
|
|
}
|
|
}
|
|
|
|
if( ~v & 1 ) {
|
|
return gcd(u, v >> 1);
|
|
}
|
|
|
|
if( u > v ) {
|
|
return gcd((u - v) >> 1, v);
|
|
}
|
|
|
|
return gcd((v - u) >> 1, u);
|
|
}
|
|
#endif
|
|
|
|
static float fast_log2(const float val) {
|
|
// Thank you Stack Overflow!
|
|
// http://stackoverflow.com/questions/9411823/fast-log2float-x-implementation-c
|
|
union {
|
|
float val;
|
|
int32_t x;
|
|
} u = { val };
|
|
float log_2 = (((u.x >> 23) & 255) - 128);
|
|
u.x &= ~(255 << 23);
|
|
u.x += (127 << 23);
|
|
log_2 += ((-0.34484843f) * u.val + 2.02466578f) * u.val - 0.67487759f;
|
|
return log_2;
|
|
}
|
|
|
|
float complex16_mag_squared_to_dbv_norm(const float c16_mag_squared) {
|
|
constexpr float input_component_max = 32768;
|
|
constexpr float mag2_max = (input_component_max * input_component_max) * 2;
|
|
constexpr float mag2_log2_max = std::log2(mag2_max);
|
|
constexpr float log_mag2_mag_factor = 0.5f;
|
|
constexpr float log2_log10_factor = std::log10(2.0f);
|
|
constexpr float log10_dbv_factor = 20.0f;
|
|
constexpr float mag2_to_db_factor = log_mag2_mag_factor * log2_log10_factor * log10_dbv_factor;
|
|
return (fast_log2(c16_mag_squared) - mag2_log2_max) * mag2_to_db_factor;
|
|
}
|
|
|
|
/* GCD implementation derived from recursive implementation at
|
|
* http://en.wikipedia.org/wiki/Binary_GCD_algorithm
|
|
*/
|
|
|
|
static constexpr uint32_t gcd_top(const uint32_t u, const uint32_t v);
|
|
|
|
static constexpr uint32_t gcd_larger(const uint32_t u, const uint32_t v) {
|
|
return (u > v) ? gcd_top((u - v) >> 1, v) : gcd_top((v - u) >> 1, u);
|
|
}
|
|
|
|
static constexpr uint32_t gcd_u_odd_v_even(const uint32_t u, const uint32_t v) {
|
|
return (~v & 1) ? gcd_top(u, v >> 1) : gcd_larger(u, v);
|
|
}
|
|
|
|
static constexpr uint32_t gcd_v_odd(const uint32_t u, const uint32_t v) {
|
|
return (v & 1)
|
|
? gcd_top(u >> 1, v)
|
|
: (gcd_top(u >> 1, v >> 1) << 1);
|
|
}
|
|
|
|
static constexpr uint32_t gcd_u_even(const uint32_t u, const uint32_t v) {
|
|
return (~u & 1)
|
|
? gcd_v_odd(u, v)
|
|
: gcd_u_odd_v_even(u, v)
|
|
;
|
|
}
|
|
|
|
static constexpr uint32_t gcd_v_zero(const uint32_t u, const uint32_t v) {
|
|
return (v == 0) ? u : gcd_u_even(u, v);
|
|
}
|
|
|
|
static constexpr uint32_t gcd_u_zero(const uint32_t u, const uint32_t v) {
|
|
return (u == 0) ? v : gcd_v_zero(u, v);
|
|
}
|
|
|
|
static constexpr uint32_t gcd_uv_equal(const uint32_t u, const uint32_t v) {
|
|
return (u == v) ? u : gcd_u_zero(u, v);
|
|
}
|
|
|
|
static constexpr uint32_t gcd_top(const uint32_t u, const uint32_t v) {
|
|
return gcd_uv_equal(u, v);
|
|
}
|
|
|
|
uint32_t gcd(const uint32_t u, const uint32_t v) {
|
|
return gcd_top(u, v);
|
|
}
|