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optimize for arm

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KubaPro010
2025-03-27 21:07:20 +01:00
parent 13bf8baaf3
commit ffd0c418e7
4 changed files with 76 additions and 16 deletions
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55
lib/filters.c
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@@ -16,26 +16,57 @@ float hard_clip(float sample, float threshold) {
}
void init_lpf(LPFFilter *filter, float cutoff, int sample_rate) {
float a = tanf(M_PI*cutoff/sample_rate);
float a2 = a*a;
float a = tanf(M_PI * cutoff / sample_rate);
float a2 = a * a;
float r, e;
for(int i = 0; i < LPF_ORDER; i++) {
r = sinf(M_PI*(2.0f*i+1.0f)/(4.0f*LPF_ORDER));
e = a2+2.0f*a*r+1.0f;
filter->A[i] = a2 / e;
filter->d1[i] = 2.0f*(1.0f-a2)/e;
filter->d2[i] = -(a2 - 2.0f * a * r + 1.0f) / e;
for (int i = 0; i < LPF_ORDER; i++) {
r = sinf(M_PI * (2.0f * i + 1.0f) / (4.0f * LPF_ORDER));
e = a2 + 2.0f * a * r + 1.0f;
float inv_e = 1.0f / e;
filter->A[i] = a2 * inv_e;
filter->d1[i] = 2.0f * (1.0f - a2) * inv_e;
filter->d2[i] = -(a2 - 2.0f * a * r + 1.0f) * inv_e;
}
}
float process_lpf(LPFFilter *filter, float x) {
float y = x;
for(int i = 0; i < LPF_ORDER; i++) {
filter->w0[i] = filter->d1[i] * filter->w1[i] + filter->d2[i] * filter->w2[i] + y;
y = filter->A[i] * (filter->w0[i] + 2.0f * filter->w1[i] + filter->w2[i]);
#if USE_NEON // Use NEON if available
float32x4_t v_y = vdupq_n_f32(y); // Load input into all lanes
for (int i = 0; i < LPF_ORDER; i += 4) { // Process 4 biquads at a time
float32x4_t v_w1 = vld1q_f32(&filter->w1[i]);
float32x4_t v_w2 = vld1q_f32(&filter->w2[i]);
float32x4_t v_d1 = vld1q_f32(&filter->d1[i]);
float32x4_t v_d2 = vld1q_f32(&filter->d2[i]);
float32x4_t v_A = vld1q_f32(&filter->A[i]);
// Compute w0 = d1 * w1 + d2 * w2 + y
float32x4_t v_w0 = vmlaq_f32(vmulq_f32(v_d1, v_w1), v_d2, v_w2);
v_w0 = vaddq_f32(v_w0, v_y);
// Compute y = A * (w0 + 2*w1 + w2)
float32x4_t v_tw1 = vaddq_f32(v_w1, v_w1); // 2*w1
float32x4_t v_sum = vaddq_f32(vaddq_f32(v_w0, v_tw1), v_w2);
v_y = vmulq_f32(v_A, v_sum); // Multiply by A
// Store updated values
vst1q_f32(&filter->w2[i], v_w1);
vst1q_f32(&filter->w1[i], v_w0);
}
return vgetq_lane_f32(v_y, 0); // Return first lane of vector
#else // Scalar fallback if NEON is not available
for (int i = 0; i < LPF_ORDER; i++) {
float w0_new = filter->d1[i] * filter->w1[i] + filter->d2[i] * filter->w2[i] + y;
y = filter->A[i] * (w0_new + 2.0f * filter->w1[i] + filter->w2[i]);
filter->w2[i] = filter->w1[i];
filter->w1[i] = filter->w0[i];
filter->w1[i] = w0_new;
}
return y;
#endif
}