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dsp.c
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dsp.c
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#include <arm_math.h>
#include "nanosdr.h"
int16_t buffer[2][AUDIO_BUFFER_LEN];
int16_t buffer2[2][AUDIO_BUFFER_LEN];
const int16_t cos_sin_table[256][2] = {
{ -32767, 10 },
{ -32757, 29 },
{ -32728, 50 },
{ -32678, 69 },
{ -32609, 88 },
{ -32521, 109 },
{ -32412, 127 },
{ -32285, 148 },
{ -32137, 166 },
{ -31971, 186 },
{ -31785, 205 },
{ -31580, 224 },
{ -31356, 243 },
{ -31113, 261 },
{ -30852, 281 },
{ -30571, 298 },
{ -30273, 317 },
{ -29956, 335 },
{ -29621, 353 },
{ -29268, 370 },
{ -28898, 388 },
{ -28510, 405 },
{ -28105, 422 },
{ -27683, 438 },
{ -27245, 455 },
{ -26790, 471 },
{ -26319, 487 },
{ -25832, 503 },
{ -25329, 518 },
{ -24811, 532 },
{ -24279, 548 },
{ -23731, 561 },
{ -23170, 576 },
{ -22594, 589 },
{ -22005, 602 },
{ -21403, 616 },
{ -20787, 628 },
{ -20159, 640 },
{ -19519, 651 },
{ -18868, 664 },
{ -18204, 674 },
{ -17530, 684 },
{ -16846, 695 },
{ -16151, 705 },
{ -15446, 714 },
{ -14732, 722 },
{ -14010, 731 },
{ -13279, 740 },
{ -12539, 746 },
{ -11793, 754 },
{ -11039, 761 },
{ -10278, 766 },
{ -9512, 773 },
{ -8739, 777 },
{ -7962, 783 },
{ -7179, 786 },
{ -6393, 791 },
{ -5602, 794 },
{ -4808, 797 },
{ -4011, 799 },
{ -3212, 802 },
{ -2410, 802 },
{ -1608, 804 },
{ -804, 804 },
{ 0, 804 },
{ 804, 804 },
{ 1608, 802 },
{ 2410, 802 },
{ 3212, 799 },
{ 4011, 797 },
{ 4808, 794 },
{ 5602, 791 },
{ 6393, 786 },
{ 7179, 783 },
{ 7962, 777 },
{ 8739, 773 },
{ 9512, 766 },
{ 10278, 761 },
{ 11039, 754 },
{ 11793, 746 },
{ 12539, 740 },
{ 13279, 731 },
{ 14010, 722 },
{ 14732, 714 },
{ 15446, 705 },
{ 16151, 695 },
{ 16846, 684 },
{ 17530, 674 },
{ 18204, 664 },
{ 18868, 651 },
{ 19519, 640 },
{ 20159, 628 },
{ 20787, 616 },
{ 21403, 602 },
{ 22005, 589 },
{ 22594, 576 },
{ 23170, 561 },
{ 23731, 548 },
{ 24279, 532 },
{ 24811, 518 },
{ 25329, 503 },
{ 25832, 487 },
{ 26319, 471 },
{ 26790, 455 },
{ 27245, 438 },
{ 27683, 422 },
{ 28105, 405 },
{ 28510, 388 },
{ 28898, 370 },
{ 29268, 353 },
{ 29621, 335 },
{ 29956, 317 },
{ 30273, 298 },
{ 30571, 281 },
{ 30852, 261 },
{ 31113, 243 },
{ 31356, 224 },
{ 31580, 205 },
{ 31785, 186 },
{ 31971, 166 },
{ 32137, 148 },
{ 32285, 127 },
{ 32412, 109 },
{ 32521, 88 },
{ 32609, 69 },
{ 32678, 50 },
{ 32728, 29 },
{ 32757, 10 },
{ 32767, -10 },
{ 32757, -29 },
{ 32728, -50 },
{ 32678, -69 },
{ 32609, -88 },
{ 32521, -109 },
{ 32412, -127 },
{ 32285, -148 },
{ 32137, -166 },
{ 31971, -186 },
{ 31785, -205 },
{ 31580, -224 },
{ 31356, -243 },
{ 31113, -261 },
{ 30852, -281 },
{ 30571, -298 },
{ 30273, -317 },
{ 29956, -335 },
{ 29621, -353 },
{ 29268, -370 },
{ 28898, -388 },
{ 28510, -405 },
{ 28105, -422 },
{ 27683, -438 },
{ 27245, -455 },
{ 26790, -471 },
{ 26319, -487 },
{ 25832, -503 },
{ 25329, -518 },
{ 24811, -532 },
{ 24279, -548 },
{ 23731, -561 },
{ 23170, -576 },
{ 22594, -589 },
{ 22005, -602 },
{ 21403, -616 },
{ 20787, -628 },
{ 20159, -640 },
{ 19519, -651 },
{ 18868, -664 },
{ 18204, -674 },
{ 17530, -684 },
{ 16846, -695 },
{ 16151, -705 },
{ 15446, -714 },
{ 14732, -722 },
{ 14010, -731 },
{ 13279, -740 },
{ 12539, -746 },
{ 11793, -754 },
{ 11039, -761 },
{ 10278, -766 },
{ 9512, -773 },
{ 8739, -777 },
{ 7962, -783 },
{ 7179, -786 },
{ 6393, -791 },
{ 5602, -794 },
{ 4808, -797 },
{ 4011, -799 },
{ 3212, -802 },
{ 2410, -802 },
{ 1608, -804 },
{ 804, -804 },
{ 0, -804 },
{ -804, -804 },
{ -1608, -802 },
{ -2410, -802 },
{ -3212, -799 },
{ -4011, -797 },
{ -4808, -794 },
{ -5602, -791 },
{ -6393, -786 },
{ -7179, -783 },
{ -7962, -777 },
{ -8739, -773 },
{ -9512, -766 },
{ -10278, -761 },
{ -11039, -754 },
{ -11793, -746 },
{ -12539, -740 },
{ -13279, -731 },
{ -14010, -722 },
{ -14732, -714 },
{ -15446, -705 },
{ -16151, -695 },
{ -16846, -684 },
{ -17530, -674 },
{ -18204, -664 },
{ -18868, -651 },
{ -19519, -640 },
{ -20159, -628 },
{ -20787, -616 },
{ -21403, -602 },
{ -22005, -589 },
{ -22594, -576 },
{ -23170, -561 },
{ -23731, -548 },
{ -24279, -532 },
{ -24811, -518 },
{ -25329, -503 },
{ -25832, -487 },
{ -26319, -471 },
{ -26790, -455 },
{ -27245, -438 },
{ -27683, -422 },
{ -28105, -405 },
{ -28510, -388 },
{ -28898, -370 },
{ -29268, -353 },
{ -29621, -335 },
{ -29956, -317 },
{ -30273, -298 },
{ -30571, -281 },
{ -30852, -261 },
{ -31113, -243 },
{ -31356, -224 },
{ -31580, -205 },
{ -31785, -186 },
{ -31971, -166 },
{ -32137, -148 },
{ -32285, -127 },
{ -32412, -109 },
{ -32521, -88 },
{ -32609, -69 },
{ -32678, -50 },
{ -32728, -29 },
{ -32757, -10 }
};
static uint32_t
cos_sin(uint16_t phase)
{
uint16_t mod = phase & 0xff;
uint32_t r = __PKHBT(0x0100, mod, 16);
uint16_t si = phase / 256;
uint16_t ci = (si + 64) & 0xff;
uint32_t cd = *(uint32_t *)&cos_sin_table[ci];
uint32_t sd = *(uint32_t *)&cos_sin_table[si];
int32_t c = __SMUAD(r, cd);
int32_t s = __SMUAD(r, sd);
c /= 256;
s /= 256;
return __PKHBT(s, c, 16);
}
uint16_t nco1_phase = 0;
uint16_t nco2_phase = 0;
#define SSB_NCO_PHASESTEP PHASESTEP(SSB_FREQ_OFFSET)
// Bi-Quad IIR Filter state
q15_t bq_i_state[4 * 3];
q15_t bq_q_state[4 * 3];
#if 0
// 6th order elliptic lowpass filter fc=1300Hz, 40dB
q15_t bq_coeffs[] = {
515, 0, -906, 515, 30977, -14714,
5171, 0, -10087, 5171, 31760, -15739,
16384, 0, -32182, 16384, 32165, -16253,
};
#else
// 6th order elliptic lowpass filter fc=1300Hz, 60dB
q15_t bq_coeffs[] = {
157, 0, -238, 157, 31237, -14936,
3643, 0, -6974, 3643, 31656, -15580,
8272, 0, -16096, 8272, 32074, -16158
};
#endif
arm_biquad_casd_df1_inst_q15 bq_i = { 3, bq_i_state, bq_coeffs, 1};
arm_biquad_casd_df1_inst_q15 bq_q = { 3, bq_q_state, bq_coeffs, 1};
// 6th order elliptic lowpass filter fc=6*1300=7800Hz
q15_t bq_coeffs_am[] = {
1186, 0, 1108, 1186, 20883, -8328,
6829, 0, -4129, 6829, 17973, -13228,
16384, 0, -14411, 16384, 16788, -15733
};
arm_biquad_casd_df1_inst_q15 bq_am_i = { 3, bq_i_state, bq_coeffs_am, 1};
arm_biquad_casd_df1_inst_q15 bq_am_q = { 3, bq_q_state, bq_coeffs_am, 1};
// 6th order elliptic lowpass filter fc=150Hz, 60dB
q15_t bq_coeffs_150hz[] = {
149, 0, -296, 149, 32593, -16210,
3579, 0, -7154, 3579, 32669, -16289,
8206, 0, -16406, 8206, 32735, -16358
};
arm_biquad_casd_df1_inst_q15 bq_cw_i = { 3, bq_i_state, bq_coeffs_150hz, 1};
arm_biquad_casd_df1_inst_q15 bq_cw_q = { 3, bq_q_state, bq_coeffs_150hz, 1};
typedef struct {
int16_t phasestep1;
int16_t phasestep2;
arm_biquad_casd_df1_inst_q15 *bq_i;
arm_biquad_casd_df1_inst_q15 *bq_q;
} weaver_demod_conf_t;
const weaver_demod_conf_t usb_demod_conf = {
SSB_NCO_PHASESTEP, SSB_NCO_PHASESTEP, &bq_i, &bq_q
};
const weaver_demod_conf_t lsb_demod_conf = {
-SSB_NCO_PHASESTEP, -SSB_NCO_PHASESTEP, &bq_i, &bq_q
};
void
demod_weaver(int16_t *src, int16_t *dst, size_t len, const weaver_demod_conf_t *dc)
{
q15_t *bufi = buffer[0];
q15_t *bufq = buffer[1];
int32_t *s = __SIMD32(src);
int32_t *d = __SIMD32(dst);
uint32_t i;
disp_fetch_samples(B_CAPTURE, BT_C_INTERLEAVE, src, NULL, len);
// shift frequency
for (i = 0; i < len/2; i++) {
uint32_t cossin = cos_sin(nco1_phase);
nco1_phase -= dc->phasestep1;
uint32_t iq = *s++;
*bufi++ = __SMLSDX(iq, cossin, 0) >> (15-0);
*bufq++ = __SMLAD(iq, cossin, 0) >> (15-0);
}
disp_fetch_samples(B_IF1, BT_IQ, buffer[0], buffer[1], len/2);
// apply low pass filter
arm_biquad_cascade_df1_q15(dc->bq_i, buffer[0], buffer2[0], len/2);
arm_biquad_cascade_df1_q15(dc->bq_q, buffer[1], buffer2[1], len/2);
disp_fetch_samples(B_IF2, BT_IQ, buffer2[0], buffer2[1], len/2);
// shift frequency inverse
bufi = buffer2[0];
bufq = buffer2[1];
for (i = 0; i < len/2; i++) {
uint32_t cossin = cos_sin(nco2_phase);
nco2_phase += dc->phasestep2;
uint32_t iq = __PKHBT(*bufi++, *bufq++, 16);
uint32_t r = __SMLAD(iq, cossin, 0) >> (15-0);
*d++ = __PKHBT(r, r, 16);
}
disp_fetch_samples(B_PLAYBACK, BT_R_INTERLEAVE, dst, NULL, len);
}
void
lsb_demod(int16_t *src, int16_t *dst, size_t len)
{
demod_weaver(src, dst, len, &lsb_demod_conf);
}
void
usb_demod(int16_t *src, int16_t *dst, size_t len)
{
demod_weaver(src, dst, len, &usb_demod_conf);
}
void
cw_demod(int16_t *src, int16_t *dst, size_t len)
{
weaver_demod_conf_t dc = {
mode_freqoffset_phasestep, cw_tone_phasestep, &bq_cw_i, &bq_cw_q
};
demod_weaver(src, dst, len, &dc);
}
__attribute__ ( ( always_inline ) ) __STATIC_INLINE
float _VSQRTF(float op1) {
float result;
__ASM volatile ("vsqrt.f32 %0,%1" : "=w"(result) : "w"(op1) );
return(result);
}
int32_t ave_z = 0;
void
am_demod(int16_t *src, int16_t *dst, size_t len)
#if defined(AM_FREQ_OFFSET) && AM_FREQ_OFFSET
{
q15_t *bufi = buffer[0];
q15_t *bufq = buffer[1];
int32_t *s = __SIMD32(src);
int32_t *d = __SIMD32(dst);
uint32_t i;
disp_fetch_samples(B_CAPTURE, BT_C_INTERLEAVE, src, NULL, len);
for (i = 0; i < len/2; i++) {
uint32_t cossin = cos_sin(nco1_phase);
nco1_phase -= mode_freqoffset_phasestep;
uint32_t iq = *s++;
*bufi++ = __SMLSDX(iq, cossin, 0) >> (15-0);
*bufq++ = __SMLAD(iq, cossin, 0) >> (15-0);
}
disp_fetch_samples(B_IF1, BT_IQ, buffer[0], buffer[1], len/2);
// apply low pass filter
arm_biquad_cascade_df1_q15(&bq_am_i, buffer[0], buffer2[0], len/2);
arm_biquad_cascade_df1_q15(&bq_am_q, buffer[1], buffer2[1], len/2);
disp_fetch_samples(B_IF2, BT_IQ, buffer2[0], buffer2[1], len/2);
//int32_t acc_z = 0;
bufi = buffer2[0];
bufq = buffer2[1];
for (i = 0; i < len/2; i++) {
int32_t x = *bufi++;
int32_t y = *bufq++;
int32_t z;
//x = x/2;
//y = y/2;
z = (int16_t)_VSQRTF((float)(x*x+y*y));
//z = (int16_t)sqrtf(x*x+y*y);
//acc_z += z;
//z -= ave_z;
if (z > 32767) z = 32767;
if (z < -32768) z = -32768;
*d++ = __PKHBT(z, z, 16);
}
//ave_z = ave_z * 0.98 + (0.02 * acc_z / (len/2));
disp_fetch_samples(B_PLAYBACK, BT_R_INTERLEAVE, dst, NULL, len);
}
#else
{
uint32_t i;
for (i = 0; i < len; i += 2) {
int32_t x = src[i];
int32_t y = src[i+1];
int32_t z;
#define DCOFFSET 16383
x = x/2;
y = y/2;
z = (int16_t)_VSQRTF((float)(x*x+y*y)) - DCOFFSET;
//z = (int16_t)sqrtf(x*x+y*y) - DCOFFSET;
dst[i] = dst[i+1] = z;
}
}
#endif
struct {
uint32_t last;
uint32_t pre1;
uint32_t pre2;
} fm_demod_state;
const int16_t arctantbl[256+2] = {
0, 128, 256, 384, 512, 640, 768, 896, 1024,
1152, 1279, 1407, 1535, 1663, 1790, 1918, 2045, 2173,
2300, 2428, 2555, 2682, 2809, 2936, 3063, 3190, 3317,
3443, 3570, 3696, 3823, 3949, 4075, 4201, 4327, 4452,
4578, 4703, 4829, 4954, 5079, 5204, 5329, 5453, 5578,
5702, 5826, 5950, 6073, 6197, 6320, 6444, 6567, 6689,
6812, 6935, 7057, 7179, 7301, 7422, 7544, 7665, 7786,
7907, 8027, 8148, 8268, 8388, 8508, 8627, 8746, 8865,
8984, 9102, 9221, 9339, 9456, 9574, 9691, 9808, 9925,
10041, 10158, 10274, 10389, 10505, 10620, 10735, 10849, 10964,
11078, 11192, 11305, 11418, 11531, 11644, 11756, 11868, 11980,
12092, 12203, 12314, 12424, 12535, 12645, 12754, 12864, 12973,
13082, 13190, 13298, 13406, 13514, 13621, 13728, 13835, 13941,
14047, 14153, 14258, 14363, 14468, 14573, 14677, 14781, 14884,
14987, 15090, 15193, 15295, 15397, 15499, 15600, 15701, 15801,
15902, 16002, 16101, 16201, 16300, 16398, 16497, 16595, 16693,
16790, 16887, 16984, 17080, 17176, 17272, 17368, 17463, 17557,
17652, 17746, 17840, 17933, 18027, 18119, 18212, 18304, 18396,
18488, 18579, 18670, 18760, 18851, 18941, 19030, 19120, 19209,
19297, 19386, 19474, 19561, 19649, 19736, 19823, 19909, 19995,
20081, 20166, 20252, 20336, 20421, 20505, 20589, 20673, 20756,
20839, 20922, 21004, 21086, 21168, 21249, 21331, 21411, 21492,
21572, 21652, 21732, 21811, 21890, 21969, 22047, 22126, 22203,
22281, 22358, 22435, 22512, 22588, 22664, 22740, 22815, 22891,
22966, 23040, 23115, 23189, 23262, 23336, 23409, 23482, 23555,
23627, 23699, 23771, 23842, 23914, 23985, 24055, 24126, 24196,
24266, 24335, 24405, 24474, 24542, 24611, 24679, 24747, 24815,
24882, 24950, 25017, 25083, 25150, 25216, 25282, 25347, 25413,
25478, 25543, 25607, 25672, 25736, 25736
};
#define Q15_PI_4 25736 // 3.14159/4*32768
static inline int16_t
atan_2iq(uint32_t iq0, uint32_t iq1)
{
int32_t re = __SMUAD(iq1, iq0); // I0*I1 + Q0*Q1
int32_t im = __SMUSDX(iq1, iq0); // I0*Q1 - I1*Q0
int32_t ang = 0;
uint8_t neg = 0;
if (re < 0) {
re = -re;
neg = !neg;
ang += -Q15_PI_4 * 4;
}
if (im < 0) {
im = -im;
neg = !neg;
}
if (im >= re) {
int32_t x = im;
im = re;
re = x;
neg = !neg;
ang = -ang - Q15_PI_4 * 2;
}
{
uint32_t d, f;
int32_t a, b;
int idx;
d = im << 0;
d /= re >> 16;
idx = (d >> 8) & 0xff;
f = d & 0xff;
a = arctantbl[idx];
b = arctantbl[idx+1];
ang += a + (((b - a) * f) >> 8);
}
if (neg)
ang = -ang;
return __SSAT(ang/32, 16);
}
void
fm_demod(int16_t *src, int16_t *dst, size_t len)
{
int32_t *s = __SIMD32(src);
int32_t *dst32 = __SIMD32(dst);
unsigned int i;
uint32_t x0 = fm_demod_state.last;
q15_t v;
disp_fetch_samples(B_CAPTURE, BT_C_INTERLEAVE, src, NULL, len);
for (i = 0; i < len; i += 2) {
uint32_t x1 = *s++;
v = atan_2iq(x0, x1);
*dst32++ = __PKHBT(v, v, 16);
x0 = x1;
}
fm_demod_state.last = x0;
disp_fetch_samples(B_PLAYBACK, BT_R_INTERLEAVE, dst, NULL, len);
}
// state variables for stereo separation
stereo_separate_state_t stereo_separate_state;
#define IF_RATE 192.0
#define PHASESTEP_NCO19KHz ((19.0*65536.0*65536.0)/IF_RATE)
void
stereo_separate_init(void)
{
stereo_separate_state.phase_accum = 0;
stereo_separate_state.phase_step_default = PHASESTEP_NCO19KHz;
stereo_separate_state.phase_step = stereo_separate_state.phase_step_default;
stereo_separate_state.corr = 0;
stereo_separate_state.integrator = 0;
stereo_separate_state.sdi = 0;
stereo_separate_state.sdq = 0;
}
// src: baseband signal (real)
// dest: 38kHz shifted subchannel (real)
void
stereo_separate(int16_t *src, int16_t *dest, int32_t length)
{
int i;
int32_t di = 0;
int32_t dq = 0;
uint32_t phase_accum = stereo_separate_state.phase_accum;
uint32_t phase_step = stereo_separate_state.phase_step;
int32_t corr = 0;
// PLL 19kHz, 38kHz frequency shift
for (i = 0; i < length; i++) {
uint32_t cs = cos_sin(phase_accum >> 16);
int16_t s = cs & 0xffff;
int16_t c = cs >> 16;
// sin(2t) = 2sin(t)cos(t)
int16_t ss = (int32_t)(c * s) >> (16 - 2);
// frequency shift
int32_t x = src[i];
dest[i] = (ss * x) >> (16 - 1);
//src[i] = src[i] / 2;
// correlate 19kHz pilot carrier
di += (c * x) >> 16;
dq += (s * x) >> 16;
phase_accum += phase_step;
}
stereo_separate_state.phase_accum = phase_accum;
// averaging correlation
di = (stereo_separate_state.sdi * 15 + di) / 16;
dq = (stereo_separate_state.sdq * 15 + dq) / 16;
stereo_separate_state.sdi = di;
stereo_separate_state.sdq = dq;
if (di > 0) {
corr = 1024 * dq / di;
//corr += stereo_separate_state.corr;
if (corr > 4095)
corr = 4095;
else if (corr < -4095)
corr = -4095;
} else {
if (dq > 0)
corr = 4095;
else if (dq < 0)
corr = -4095;
//phase_step = stereo_separate_state.phase_step_default;
}
if (corr != 0) {
// for monitoring
stereo_separate_state.corr = corr;
stereo_separate_state.corr_ave = (stereo_separate_state.corr_ave * 15 + corr) / 16;
int32_t d = stereo_separate_state.corr_ave - corr;
int32_t sd = (stereo_separate_state.corr_std * 15 + d * d) / 16;
if (sd > 32767)
sd = 32767;
stereo_separate_state.corr_std = sd;
// feedback phase step
phase_step = stereo_separate_state.phase_step_default
- stereo_separate_state.integrator - corr * 128;
//phase_step += -stereo_separate_state.corr_ave;
stereo_separate_state.phase_step = phase_step;
if (stereo_separate_state.corr_std < 100)
stereo_separate_state.integrator += stereo_separate_state.corr_ave;
}
}
void
stereo_matrix(int16_t *s1, int16_t *s2, int len)
{
int i;
for (i = 0; i < len; i++) {
uint32_t x1 = *s1;
uint32_t x2 = *s2;
uint32_t l = __QADD16(x1, x2);
uint32_t r = __QSUB16(x1, x2);
*s1++ = l;
*s2++ = r;
}
}
void
stereo_matrix2(int16_t *s1, int16_t *s2, int16_t *dst, int len)
{
int i;
for (i = 0; i < len; i++) {
uint32_t x1 = *s1++;
uint32_t x2 = *s2++;
uint32_t l = __QADD16(x1, x2);
uint32_t r = __QSUB16(x1, x2);
*dst++ = l;
*dst++ = r;
}
}
void
stereo_matrix3(int16_t *s1, int16_t *s2, int16_t *dst, int len)
{
int i;
for (i = 0; i < len; i += 4) {
int32_t x1 = *s1++ / 4;
int32_t x2 = *s2++ / 4;
int32_t l = __QADD16(x1, x2);
int32_t r = __QSUB16(x1, x2);
x1 = *s1++ / 4;
x2 = *s2++ / 4;
int32_t l0 = __QADD16(x1, x2);
int32_t r0 = __QSUB16(x1, x2);
l = __QADD16(l, l0);
r = __QADD16(r, r0);
x1 = *s1++ / 4;
x2 = *s2++ / 4;
l0 = __QADD16(x1, x2);
r0 = __QSUB16(x1, x2);
l = __QADD16(l, l0);
r = __QADD16(r, r0);
x1 = *s1++ / 4;
x2 = *s2++ / 4;
l0 = __QADD16(x1, x2);
r0 = __QSUB16(x1, x2);
l = __QADD16(l, l0);
r = __QADD16(r, r0);
*dst++ = l;
*dst++ = r;
*dst++ = l;
*dst++ = r;
*dst++ = l;
*dst++ = r;
*dst++ = l;
*dst++ = r;
}
}
static inline void
fm_adj_filter(int16_t *src, size_t len)
{
int32_t *s = __SIMD32(src);
unsigned int i;
uint32_t x1 = fm_demod_state.pre1;
uint32_t x2 = fm_demod_state.pre2;
uint32_t zero = 0;
uint32_t k12 = 0x5ae1eccd;
//uint32_t k12 = 0x51ecea3d;
for (i = 0; i < len; i += 2) {
int32_t x0 = *s;
int32_t acc_i = 0;
uint32_t i12 = __PKHBT(x2, x1, 16);
uint32_t i0_ = __PKHBT(zero, x0, 16);
acc_i = __SMLAD(k12, i12, acc_i);
acc_i = __SMLADX(k12, i0_, acc_i);
int32_t acc_q = 0;
uint32_t q12 = __PKHTB(x1, x2, 16);
uint32_t q0_ = __PKHTB(x0, zero, 16);
acc_q = __SMLAD(k12, q12, acc_q);
acc_q = __SMLADX(k12, q0_, acc_q);
#if 1
acc_i = __SSAT(acc_i >>14, 16);
acc_q = __SSAT(acc_q >>14, 16);
*s++ = __PKHBT(acc_i, acc_q, 16);
#else
*s++ = __PKHTB(acc_q, acc_i, 16);
#endif
x2 = x1;
x1 = x0;
}
fm_demod_state.pre1 = x1;
fm_demod_state.pre2 = x2;
}
void
fm_demod0(int16_t *src, int16_t *dst, size_t len)
{
int32_t *s = __SIMD32(src);
uint32_t x0 = fm_demod_state.last;
unsigned int i;
for (i = 0; i < len; i += 2) {
uint32_t x1 = *s++;
*dst++ = atan_2iq(x0, x1);
x0 = x1;
}
fm_demod_state.last = x0;
}
void
fm_demod_stereo(int16_t *src, int16_t *dst, size_t len)
{
// apply frequency response adjustment
fm_adj_filter(src, len);
disp_fetch_samples(B_CAPTURE, BT_C_INTERLEAVE, src, NULL, len);
fm_demod0(src, buffer[0], len);
disp_fetch_samples(B_IF1, BT_REAL, buffer[0], NULL, len/2);
stereo_separate(buffer[0], buffer2[0], len/2);
disp_fetch_samples(B_IF2, BT_REAL, buffer2[0], NULL, len/2);
stereo_matrix2(buffer[0], buffer2[0], dst, len/2);
//stereo_matrix3(buffer[0], buffer2[0], dst, len/2);
disp_fetch_samples(B_PLAYBACK, BT_R_INTERLEAVE, dst, NULL, len);
}
#if 0
void
fir_filter_stereo()
{
const uint32_t *coeff;
const uint16_t *src1 = (const uint16_t *)RESAMPLE_STATE;
const uint16_t *src2 = (const uint16_t *)RESAMPLE2_STATE;
const uint32_t *s1, *s2;
int32_t tail = RESAMPLE_BUFFER_SIZE;
int32_t idx = resample_state.index;
int32_t acc1, acc2;
int i, j;
int cur = audio_state.write_current;
uint16_t *dest = (uint16_t *)AUDIO_BUFFER;
float val1 = resample_state.deemphasis_value;
float val2 = resample_state.deemphasis_value2;
while (idx < tail) {
coeff = (uint32_t*)resample_fir_coeff[idx % 2];
acc1 = 0;
acc2 = 0;
s1 = (const uint32_t*)&src1[idx >> 1];
s2 = (const uint32_t*)&src2[idx >> 1];
for (j = 0; j < RESAMPLE_NUM_TAPS / 2; j++) {
uint32_t x1 = *s1++;
uint32_t x2 = *s2++;
//uint32_t l = __SADD16(x1, x2);
//uint32_t r = __SSUB16(x1, x2);
acc1 = __SMLAD(x1, *coeff, acc1);
acc2 = __SMLAD(x2, *coeff, acc2);
coeff++;
}
// deemphasis with time constant
val1 = (float)acc1 * resample_state.deemphasis_rest + val1 * resample_state.deemphasis_mult;
val2 = (float)acc2 * resample_state.deemphasis_rest + val2 * resample_state.deemphasis_mult;
int32_t left = val1 + val2;
int32_t right = val1 - val2;
dest[cur++] = left >> (16 - RESAMPLE_GAINBITS);
dest[cur++] = right >> (16 - RESAMPLE_GAINBITS);
//dest[cur++] = __SSAT((int32_t)(val1-val2) >> (16 - RESAMPLE_GAINBITS), 16);
//dest[cur++] = __SSAT((int32_t)(val1) >> (16 - RESAMPLE_GAINBITS), 16);
//dest[cur++] = __SSAT((int32_t)(val1) >> (16 - RESAMPLE_GAINBITS), 16);
//dest[cur++] = 0;
cur %= AUDIO_BUFFER_SIZE / 2;
audio_state.write_total += 2;
idx += 13; /* 2/13 decimation: 2 samples per loop */
}
resample_state.deemphasis_value = val1;
resample_state.deemphasis_value2 = val2;
audio_state.write_current = cur;
resample_state.index = idx - tail;
uint32_t *state = (uint32_t *)RESAMPLE_STATE;
src1 = &src1[tail / sizeof(*src1)];
for (i = 0; i < RESAMPLE_STATE_SIZE / sizeof(uint32_t); i++) {
//*state++ = *src1++;
__asm__ volatile ("ldr r0, [%0], #+4\n" : : "r" (src1) : "r0");
__asm__ volatile ("str r0, [%0], #+4\n" : : "r" (state) : "r0");
}
state = (uint32_t *)RESAMPLE2_STATE;
src2 = &src2[tail / sizeof(*src2)];
for (i = 0; i < RESAMPLE_STATE_SIZE / sizeof(uint32_t); i++) {
//*state++ = *src2++;
__asm__ volatile ("ldr r0, [%0], #+4\n" : : "r" (src2) : "r0");
__asm__ volatile ("str r0, [%0], #+4\n" : : "r" (state) : "r0");
}
}
#endif
void
dsp_init(void)
{
stereo_separate_init();
}