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Implement proper resampling on AudioPCI.

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This commit is contained in:
SarahW 2018-03-13 21:51:40 +00:00
commit 2e395d2ce8
1 changed files with 126 additions and 11 deletions
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137
src/sound_audiopci.c
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@ -1,5 +1,6 @@
#include <stdlib.h>
#include <string.h>
#include <math.h>
#include "ibm.h"
#include "device.h"
#include "io.h"
@ -7,6 +8,12 @@
#include "pci.h"
#include "sound.h"
#define N 16
#define ES1371_NCoef 91
static float low_fir_es1371_coef[ES1371_NCoef];
typedef struct es1371_t
{
uint8_t pci_command, pci_serr;
@ -49,6 +56,9 @@ typedef struct es1371_t
int16_t buffer_l[64], buffer_r[64];
int buffer_pos, buffer_pos_end;
int filtered_l[32], filtered_r[32];
int f_pos;
int16_t out_l, out_r;
int32_t vol_l, vol_r;
@ -462,6 +472,7 @@ static void es1371_outl(uint16_t port, uint32_t val, void *p)
case 0x71:
es1371->dac[0].vf = (es1371->dac[0].vf & ~0x1f8000) | ((val & 0xfc00) << 5);
es1371->dac[0].ac = (es1371->dac[0].ac & ~0x7f8000) | ((val & 0x00ff) << 15);
es1371->dac[0].f_pos = 0;
break;
case 0x72:
es1371->dac[0].ac = (es1371->dac[0].ac & ~0x7fff) | (val & 0x7fff);
@ -473,6 +484,7 @@ static void es1371_outl(uint16_t port, uint32_t val, void *p)
case 0x75:
es1371->dac[1].vf = (es1371->dac[1].vf & ~0x1f8000) | ((val & 0xfc00) << 5);
es1371->dac[1].ac = (es1371->dac[1].ac & ~0x7f8000) | ((val & 0x00ff) << 15);
es1371->dac[1].f_pos = 0;
break;
case 0x76:
es1371->dac[1].ac = (es1371->dac[1].ac & ~0x7fff) | (val & 0x7fff);
@ -968,15 +980,60 @@ static void es1371_fetch(es1371_t *es1371, int dac_nr)
}
}
static void es1371_next_sample(es1371_t *es1371, int dac_nr)
static inline float low_fir_es1371(int dac_nr, int i, float NewSample)
{
static float x[2][2][128]; //input samples
static int x_pos[2] = {0, 0};
float out = 0.0;
int read_pos;
int n_coef;
int pos = x_pos[dac_nr];
x[dac_nr][i][pos] = NewSample;
/*Since only 1/16th of input samples are non-zero, only filter those that
are valid.*/
read_pos = (pos + 15) & (127 & ~15);
n_coef = (16 - pos) & 15;
while (n_coef < ES1371_NCoef)
{
out += low_fir_es1371_coef[n_coef] * x[dac_nr][i][read_pos];
read_pos = (read_pos + 16) & (127 & ~15);
n_coef += 16;
}
if (i == 1)
{
x_pos[dac_nr] = (x_pos[dac_nr] + 1) & 127;
if (x_pos[dac_nr] > 127)
x_pos[dac_nr] = 0;
}
return out;
}
static void es1371_next_sample_filtered(es1371_t *es1371, int dac_nr, int out_idx)
{
int out_l, out_r;
int c;
if ((es1371->dac[dac_nr].buffer_pos - es1371->dac[dac_nr].buffer_pos_end) >= 0)
{
es1371_fetch(es1371, dac_nr);
}
es1371->dac[dac_nr].out_l = es1371->dac[dac_nr].buffer_l[es1371->dac[dac_nr].buffer_pos & 63];
es1371->dac[dac_nr].out_r = es1371->dac[dac_nr].buffer_r[es1371->dac[dac_nr].buffer_pos & 63];
out_l = es1371->dac[dac_nr].buffer_l[es1371->dac[dac_nr].buffer_pos & 63];
out_r = es1371->dac[dac_nr].buffer_r[es1371->dac[dac_nr].buffer_pos & 63];
es1371->dac[dac_nr].filtered_l[out_idx] = (int)low_fir_es1371(dac_nr, 0, (float)out_l);
es1371->dac[dac_nr].filtered_r[out_idx] = (int)low_fir_es1371(dac_nr, 1, (float)out_r);
for (c = 1; c < 16; c++)
{
es1371->dac[dac_nr].filtered_l[out_idx+c] = (int)low_fir_es1371(dac_nr, 0, 0);
es1371->dac[dac_nr].filtered_r[out_idx+c] = (int)low_fir_es1371(dac_nr, 1, 0);
}
// pclog("Use %02x %04x %04x\n", es1371->dac[dac_nr].buffer_pos & 63, es1371->dac[dac_nr].out_l, es1371->dac[dac_nr].out_r);
es1371->dac[dac_nr].buffer_pos++;
@ -1026,12 +1083,22 @@ static void es1371_poll(void *p)
if (es1371->int_ctrl & INT_DAC1_EN)
{
int frac = es1371->dac[0].ac & 0x7fff;
int idx = es1371->dac[0].ac >> 15;
int samp1_l = es1371->dac[0].filtered_l[idx];
int samp1_r = es1371->dac[0].filtered_r[idx];
int samp2_l = es1371->dac[0].filtered_l[(idx + 1) & 31];
int samp2_r = es1371->dac[0].filtered_r[(idx + 1) & 31];
es1371->dac[0].out_l = ((samp1_l * (0x8000 - frac)) + (samp2_l * frac)) >> 15;
es1371->dac[0].out_r = ((samp1_r * (0x8000 - frac)) + (samp2_r * frac)) >> 15;
// pclog("1Samp %i %i %08x\n", es1371->dac[0].curr_samp_ct, es1371->dac[0].samp_ct, es1371->dac[0].ac);
es1371->dac[0].ac += es1371->dac[0].vf;
if (es1371->dac[0].ac & (~0 << (15+4)))
es1371->dac[0].ac &= ((32 << 15) - 1);
if ((es1371->dac[0].ac >> (15+4)) != es1371->dac[0].f_pos)
{
es1371->dac[0].ac &= ~(~0 << (15+4));
es1371_next_sample(es1371, 0);
es1371_next_sample_filtered(es1371, 0, es1371->dac[0].f_pos ? 16 : 0);
es1371->dac[0].f_pos = (es1371->dac[0].f_pos + 1) & 1;
es1371->dac[0].curr_samp_ct++;
if (es1371->dac[0].curr_samp_ct == es1371->dac[0].samp_ct)
@ -1049,21 +1116,33 @@ static void es1371_poll(void *p)
if (es1371->int_ctrl & INT_DAC2_EN)
{
int frac = es1371->dac[1].ac & 0x7fff;
int idx = es1371->dac[1].ac >> 15;
int samp1_l = es1371->dac[1].filtered_l[idx];
int samp1_r = es1371->dac[1].filtered_r[idx];
int samp2_l = es1371->dac[1].filtered_l[(idx + 1) & 31];
int samp2_r = es1371->dac[1].filtered_r[(idx + 1) & 31];
es1371->dac[1].out_l = ((samp1_l * (0x8000 - frac)) + (samp2_l * frac)) >> 15;
es1371->dac[1].out_r = ((samp1_r * (0x8000 - frac)) + (samp2_r * frac)) >> 15;
// pclog("2Samp %i %i %08x\n", es1371->dac[1].curr_samp_ct, es1371->dac[1].samp_ct, es1371->dac[1].ac);
es1371->dac[1].ac += es1371->dac[1].vf;
if (es1371->dac[1].ac & (~0 << (15+4)))
es1371->dac[1].ac &= ((32 << 15) - 1);
if ((es1371->dac[1].ac >> (15+4)) != es1371->dac[1].f_pos)
{
es1371->dac[1].ac &= ~(~0 << (15+4));
es1371_next_sample(es1371, 1);
es1371_next_sample_filtered(es1371, 1, es1371->dac[1].f_pos ? 16 : 0);
es1371->dac[1].f_pos = (es1371->dac[1].f_pos + 1) & 1;
es1371->dac[1].curr_samp_ct++;
if (es1371->dac[1].curr_samp_ct > es1371->dac[1].samp_ct)
if (es1371->dac[1].curr_samp_ct == es1371->dac[1].samp_ct)
{
es1371->dac[1].curr_samp_ct = 0;
// es1371->dac[1].curr_samp_ct = 0;
// pclog("DAC2 IRQ\n");
es1371->int_status |= INT_STATUS_DAC2;
es1371_update_irqs(es1371);
}
if (es1371->dac[1].curr_samp_ct > es1371->dac[1].samp_ct)
es1371->dac[1].curr_samp_ct = 0;
}
}
}
@ -1081,6 +1160,40 @@ static void es1371_get_buffer(int32_t *buffer, int len, void *p)
es1371->pos = 0;
}
static inline double sinc(double x)
{
return sin(M_PI * x) / (M_PI * x);
}
static void generate_es1371_filter()
{
/*Cutoff frequency = 1 / 32*/
float fC = 1.0 / 32.0;
float gain;
int n;
for (n = 0; n < ES1371_NCoef; n++)
{
/*Blackman window*/
double w = 0.42 - (0.5 * cos((2.0*n*M_PI)/(double)(ES1371_NCoef-1))) + (0.08 * cos((4.0*n*M_PI)/(double)(ES1371_NCoef-1)));
/*Sinc filter*/
double h = sinc(2.0 * fC * ((double)n - ((double)(ES1371_NCoef-1) / 2.0)));
/*Create windowed-sinc filter*/
low_fir_es1371_coef[n] = w * h;
}
low_fir_es1371_coef[(ES1371_NCoef - 1) / 2] = 1.0;
gain = 0.0;
for (n = 0; n < ES1371_NCoef; n++)
gain += low_fir_es1371_coef[n] / (float)N;
/*Normalise filter, to produce unity gain*/
for (n = 0; n < ES1371_NCoef; n++)
low_fir_es1371_coef[n] /= gain;
}
static void *es1371_init()
{
es1371_t *es1371 = malloc(sizeof(es1371_t));
@ -1091,6 +1204,8 @@ static void *es1371_init()
es1371->card = pci_add(es1371_pci_read, es1371_pci_write, es1371);
timer_add(es1371_poll, &es1371->dac[1].time, TIMER_ALWAYS_ENABLED, es1371);
generate_es1371_filter();
return es1371;
}