From 7a5bcadc232c29dc785e81ba026e2e6588de0584 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jan=20Hamal=20Dvo=C5=99=C3=A1k?= <mordae@anilinux.org>
Date: Sat, 27 Jan 2024 11:55:47 +0100
Subject: [PATCH] Remove filters that did not pay off
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Signed-off-by: Jan Hamal Dvořák <mordae@anilinux.org>
---
 src/main.c | 70 ++----------------------------------------------------
 1 file changed, 2 insertions(+), 68 deletions(-)

diff --git a/src/main.c b/src/main.c
index 2f21326..ed88f5e 100644
--- a/src/main.c
+++ b/src/main.c
@@ -41,9 +41,7 @@
 #define RSSI_ALPHA 1
 #define LPF_SAMPLES 8 /* 8 */
 #define HPF_ALPHA 1   /* 1 */
-#define IIR_ON 0
 #define SPEED 3
-#define PRIME_DELTA 1
 
 #define SLEEP_US 16666
 
@@ -343,53 +341,12 @@ inline static __unused int cheap_angle_diff(int angle1, int angle2)
 	return diff;
 }
 
-#if SPEED == 3
-inline static unsigned popcount(unsigned v)
+inline static __unused unsigned popcount(unsigned v)
 {
 	v = v - ((v >> 1) & 0x55555555);
 	v = (v & 0x33333333) + ((v >> 2) & 0x33333333);
 	return (((v + (v >> 4)) & 0x0f0f0f0f) * 0x01010101) >> 24;
 }
-#endif
-
-#define NPOLE 3
-#define NZERO 3
-float acoeff[] = { -0.16915568299951372, 0.8087276367484724, -1.3271950516294135, 1 };
-float bcoeff[] = { 1, 3, 3, 1 };
-float gain = 25.610088152223362;
-
-inline static __unused float applyfilter(float v, float *xv, float *yv)
-{
-	int i;
-	float out = 0;
-	for (i = 0; i < NZERO; i++) {
-		xv[i] = xv[i + 1];
-	}
-	xv[NZERO] = v / gain;
-	for (i = 0; i < NPOLE; i++) {
-		yv[i] = yv[i + 1];
-	}
-	for (i = 0; i <= NZERO; i++) {
-		out += xv[i] * bcoeff[i];
-	}
-	for (i = 0; i < NPOLE; i++) {
-		out -= yv[i] * acoeff[i];
-	}
-	yv[NPOLE] = out;
-	return out;
-}
-
-inline static __unused float angle_diff(float angle1, float angle2)
-{
-	float diff = fmod(angle2 - angle1, 360.0f);
-
-	if (diff > 180.0f)
-		diff -= 360.0f;
-	else if (diff < -180.0f)
-		diff += 360.0f;
-
-	return diff;
-}
 
 static __unused bool is_prime_or_one(int n)
 {
@@ -435,14 +392,6 @@ static void rf_rx(void)
 	}
 #endif
 
-#if IIR_ON
-	float xvI[] = { 0, 0, 0, 0 };
-	float yvI[] = { 0, 0, 0, 0 };
-
-	float xvQ[] = { 0, 0, 0, 0 };
-	float yvQ[] = { 0, 0, 0, 0 };
-#endif
-
 #if SPEED == 2
 	interp0->ctrl[0] = (31 << SIO_INTERP0_CTRL_LANE0_MASK_MSB_LSB) |
 			   (0 << SIO_INTERP0_CTRL_LANE0_MASK_LSB_LSB) |
@@ -502,22 +451,12 @@ static void rf_rx(void)
 
 		int delta = ~dma_hw->ch[rx_dma].transfer_count - prev_transfers;
 
-		int acceptable_deviation = delta_watermark / 16 + 1;
+		int acceptable_deviation = delta_watermark / 32 + 1;
 
 		if (delta < (delta_watermark - acceptable_deviation)) {
-#if PRIME_DELTA
-			while (!is_prime_or_one(--delta_watermark))
-				;
-#else
 			delta_watermark--;
-#endif
 		} else if (delta > (delta_watermark + acceptable_deviation)) {
-#if PRIME_DELTA
-			while (!is_prime_or_one(++delta_watermark))
-				;
-#else
 			delta_watermark++;
-#endif
 		}
 
 		while (delta < delta_watermark) {
@@ -657,11 +596,6 @@ static void rf_rx(void)
 		Q = lpQavg3 / (LPF_SAMPLES * LPF_SAMPLES * LPF_SAMPLES);
 #endif
 
-#if IIR_ON
-		I = applyfilter(I, xvI, yvI);
-		Q = applyfilter(Q, xvQ, yvQ);
-#endif
-
 		if ((Q < 0) ^ (prevQ < 0)) {
 			stride *= ((I < 0) ^ (Q < 0)) ? 1 : -1;
 			period = (63 * period + stride) / 64;