mirror of
https://github.com/CTCaer/RetroArch.git
synced 2024-12-30 14:53:39 +00:00
267 lines
7.6 KiB
C
267 lines
7.6 KiB
C
/* SSNES - A Super Nintendo Entertainment System (SNES) Emulator frontend for libsnes.
|
|
* Copyright (C) 2010-2012 - Hans-Kristian Arntzen
|
|
*
|
|
* Some code herein may be based on code found in BSNES.
|
|
*
|
|
* SSNES 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 Found-
|
|
* ation, either version 3 of the License, or (at your option) any later version.
|
|
*
|
|
* SSNES 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 SSNES.
|
|
* If not, see <http://www.gnu.org/licenses/>.
|
|
*/
|
|
|
|
// Bog-standard windowed SINC implementation.
|
|
// Only suitable as an upsampler, as there is no low-pass filter stage.
|
|
|
|
#include "resampler.h"
|
|
#include <math.h>
|
|
#include <stdint.h>
|
|
#include <stdlib.h>
|
|
#include <malloc.h>
|
|
#include <string.h>
|
|
|
|
#if __SSE__
|
|
#include <xmmintrin.h>
|
|
#endif
|
|
|
|
#define PHASE_BITS 8
|
|
#define SUBPHASE_BITS 16
|
|
|
|
#define PHASES (1 << PHASE_BITS)
|
|
#define PHASES_SHIFT (SUBPHASE_BITS)
|
|
#define SUBPHASES (1 << SUBPHASE_BITS)
|
|
#define SUBPHASES_SHIFT 0
|
|
#define SUBPHASES_MASK ((1 << SUBPHASE_BITS) - 1)
|
|
#define PHASES_WRAP (1 << (PHASE_BITS + SUBPHASE_BITS))
|
|
#define FRAMES_SHIFT (PHASE_BITS + SUBPHASE_BITS)
|
|
|
|
#define SIDELOBES 8
|
|
|
|
struct ssnes_resampler
|
|
{
|
|
float phase_table[PHASES + 1][SIDELOBES];
|
|
float delta_table[PHASES + 1][SIDELOBES];
|
|
float buffer_l[2 * SIDELOBES];
|
|
float buffer_r[2 * SIDELOBES];
|
|
|
|
uint32_t time;
|
|
};
|
|
|
|
static inline double sinc(double val)
|
|
{
|
|
if (fabs(val) < 0.00001)
|
|
return 1.0;
|
|
else
|
|
return sin(val) / val;
|
|
}
|
|
|
|
static inline double blackman(double index)
|
|
{
|
|
index *= 0.5;
|
|
index += 0.5;
|
|
|
|
double alpha = 0.16;
|
|
double a0 = (1.0 - alpha) / 2.0;
|
|
double a1 = 0.5;
|
|
double a2 = alpha / 2.0;
|
|
|
|
return a0 - a1 * cos(2.0 * M_PI * index) + a2 * cos(4.0 * M_PI * index);
|
|
}
|
|
|
|
static void init_sinc_table(ssnes_resampler_t *resamp)
|
|
{
|
|
for (unsigned i = 0; i <= PHASES; i++)
|
|
{
|
|
for (unsigned j = 0; j < SIDELOBES; j++)
|
|
{
|
|
double sinc_phase = M_PI * ((double)i / PHASES + (double)j);
|
|
resamp->phase_table[i][j] = sinc(sinc_phase) * blackman(sinc_phase / SIDELOBES);
|
|
}
|
|
}
|
|
|
|
// Optimize linear interpolation.
|
|
for (unsigned i = 0; i < PHASES; i++)
|
|
for (unsigned j = 0; j < SIDELOBES; j++)
|
|
resamp->delta_table[i][j] = resamp->phase_table[i + 1][j] - resamp->phase_table[i][j];
|
|
}
|
|
|
|
ssnes_resampler_t *resampler_new(void)
|
|
{
|
|
ssnes_resampler_t *re = memalign(16, sizeof(*re));
|
|
if (!re)
|
|
return NULL;
|
|
|
|
memset(re, 0, sizeof(*re));
|
|
|
|
init_sinc_table(re);
|
|
return re;
|
|
}
|
|
|
|
#if __SSE__
|
|
static void process_sinc(ssnes_resampler_t *resamp, float * restrict out_buffer)
|
|
{
|
|
__m128 sum_l = _mm_setzero_ps();
|
|
__m128 sum_r = _mm_setzero_ps();
|
|
|
|
const float *buffer_l = resamp->buffer_l;
|
|
const float *buffer_r = resamp->buffer_r;
|
|
|
|
unsigned phase = resamp->time >> PHASES_SHIFT;
|
|
unsigned delta = (resamp->time >> SUBPHASES_SHIFT) & SUBPHASES_MASK;
|
|
__m128 delta_f = _mm_set1_ps((float)delta / SUBPHASES);
|
|
|
|
const float *phase_table = resamp->phase_table[phase];
|
|
const float *delta_table = resamp->delta_table[phase];
|
|
|
|
__m128 sinc_vals[SIDELOBES / 4];
|
|
for (unsigned i = 0; i < SIDELOBES; i += 4)
|
|
{
|
|
__m128 phases = _mm_load_ps(phase_table + i);
|
|
__m128 deltas = _mm_load_ps(delta_table + i);
|
|
sinc_vals[i / 4] = _mm_add_ps(phases, _mm_mul_ps(deltas, delta_f));
|
|
}
|
|
|
|
// Older data.
|
|
for (unsigned i = 0; i < SIDELOBES; i += 4)
|
|
{
|
|
__m128 buf_l = _mm_loadr_ps(buffer_l + SIDELOBES - 4 - i);
|
|
sum_l = _mm_add_ps(sum_l, _mm_mul_ps(buf_l, sinc_vals[i / 4]));
|
|
|
|
__m128 buf_r = _mm_loadr_ps(buffer_r + SIDELOBES - 4 - i);
|
|
sum_r = _mm_add_ps(sum_r, _mm_mul_ps(buf_r, sinc_vals[i / 4]));
|
|
}
|
|
|
|
// Newer data.
|
|
unsigned reverse_phase = PHASES_WRAP - resamp->time;
|
|
phase = reverse_phase >> PHASES_SHIFT;
|
|
delta = (reverse_phase >> SUBPHASES_SHIFT) & SUBPHASES_MASK;
|
|
delta_f = _mm_set1_ps((float)delta / SUBPHASES);
|
|
|
|
phase_table = resamp->phase_table[phase];
|
|
delta_table = resamp->delta_table[phase];
|
|
|
|
for (unsigned i = 0; i < SIDELOBES; i += 4)
|
|
{
|
|
__m128 phases = _mm_load_ps(phase_table + i);
|
|
__m128 deltas = _mm_load_ps(delta_table + i);
|
|
sinc_vals[i / 4] = _mm_add_ps(phases, _mm_mul_ps(deltas, delta_f));
|
|
}
|
|
|
|
for (unsigned i = 0; i < SIDELOBES; i += 4)
|
|
{
|
|
__m128 buf_l = _mm_load_ps(buffer_l + SIDELOBES + i);
|
|
sum_l = _mm_add_ps(sum_l, _mm_mul_ps(buf_l, sinc_vals[i / 4]));
|
|
|
|
__m128 buf_r = _mm_load_ps(buffer_r + SIDELOBES + i);
|
|
sum_r = _mm_add_ps(sum_r, _mm_mul_ps(buf_r, sinc_vals[i / 4]));
|
|
}
|
|
|
|
// This can be done faster with _mm_hadd_ps(), but it's SSE3 :(
|
|
__m128 sum_shuf_l = _mm_shuffle_ps(sum_l, sum_r, _MM_SHUFFLE(1, 0, 1, 0));
|
|
__m128 sum_shuf_r = _mm_shuffle_ps(sum_l, sum_r, _MM_SHUFFLE(3, 2, 3, 2));
|
|
__m128 sum = _mm_add_ps(sum_shuf_l, sum_shuf_r);
|
|
|
|
union
|
|
{
|
|
float f[4];
|
|
__m128 v;
|
|
} u;
|
|
u.v = sum;
|
|
|
|
out_buffer[0] = u.f[0] + u.f[1];
|
|
out_buffer[1] = u.f[2] + u.f[3];
|
|
}
|
|
#else // Plain ol' C99
|
|
static void process_sinc(struct maru_resampler *resamp, float * restrict out_buffer)
|
|
{
|
|
float sum_l = 0.0f;
|
|
float sum_r = 0.0f;
|
|
const float *buffer_l = resamp->buffer_l;
|
|
const float *buffer_r = resamp->buffer_r;
|
|
|
|
unsigned phase = resamp->time >> PHASES_SHIFT;
|
|
unsigned delta = (resamp->time >> SUBPHASES_SHIFT) & SUBPHASES_MASK;
|
|
float delta_f = (float)delta / SUBPHASES;
|
|
|
|
const float *phase_table = resamp->phase_table[phase];
|
|
const float *delta_table = resamp->delta_table[phase];
|
|
|
|
float sinc_vals[SIDELOBES];
|
|
for (unsigned i = 0; i < SIDELOBES; i++)
|
|
sinc_vals[i] = phase_table[i] + delta_f * delta_table[i];
|
|
|
|
// Older data.
|
|
for (unsigned i = 0; i < SIDELOBES; i++)
|
|
{
|
|
sum_l += buffer_l[SIDELOBES - 1 - i] * sinc_vals[i];
|
|
sum_r += buffer_r[SIDELOBES - 1 - i] * sinc_vals[i];
|
|
}
|
|
|
|
// Newer data.
|
|
unsigned reverse_phase = PHASES_WRAP - resamp->time;
|
|
phase = reverse_phase >> PHASES_SHIFT;
|
|
delta = (reverse_phase >> SUBPHASES_SHIFT) & SUBPHASES_MASK;
|
|
delta_f = (float)delta / SUBPHASES;
|
|
|
|
phase_table = resamp->phase_table[phase];
|
|
delta_table = resamp->delta_table[phase];
|
|
|
|
for (unsigned i = 0; i < SIDELOBES; i++)
|
|
sinc_vals[i] = phase_table[i] + delta_f * delta_table[i];
|
|
|
|
for (unsigned i = 0; i < SIDELOBES; i++)
|
|
{
|
|
sum_l += buffer_l[SIDELOBES + i] * sinc_vals[i];
|
|
sum_r += buffer_r[SIDELOBES + i] * sinc_vals[i];
|
|
}
|
|
|
|
out_buffer[0] = sum_l;
|
|
out_buffer[1] = sum_r;
|
|
}
|
|
#endif
|
|
|
|
void resampler_process(ssnes_resampler_t *re, struct resampler_data *data)
|
|
{
|
|
uint32_t ratio = PHASES_WRAP / data->ratio;
|
|
|
|
const float *input = data->data_in;
|
|
float *output = data->data_out;
|
|
size_t frames = data->input_frames;
|
|
size_t out_frames = 0;
|
|
|
|
while (frames)
|
|
{
|
|
process_sinc(re, output);
|
|
output += 2;
|
|
out_frames++;
|
|
|
|
re->time += ratio;
|
|
while (re->time >= PHASES_WRAP)
|
|
{
|
|
memmove(re->buffer_l, re->buffer_l + 1,
|
|
sizeof(re->buffer_l) - sizeof(float));
|
|
memmove(re->buffer_r, re->buffer_r + 1,
|
|
sizeof(re->buffer_r) - sizeof(float));
|
|
|
|
re->buffer_l[2 * SIDELOBES - 1] = *input++;
|
|
re->buffer_r[2 * SIDELOBES - 1] = *input++;
|
|
|
|
re->time -= PHASES_WRAP;
|
|
frames--;
|
|
}
|
|
}
|
|
|
|
data->output_frames = out_frames;
|
|
}
|
|
|
|
void resampler_free(ssnes_resampler_t *re)
|
|
{
|
|
free(re);
|
|
}
|
|
|