From 1aaed3fe42280aa65b814919d51627c1edcbbcc4 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jan=20Hamal=20Dvo=C5=99=C3=A1k?= <mordae@anilinux.org>
Date: Wed, 24 Jan 2024 23:49:36 +0100
Subject: [PATCH] Enable prime checks for LO delta
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Signed-off-by: Jan Hamal Dvořák <mordae@anilinux.org>
---
src/main.c | 27 +++++++++++++++++++++++++--
1 file changed, 25 insertions(+), 2 deletions(-)
diff --git a/src/main.c b/src/main.c
index b053ca4..16caaf8 100644
--- a/src/main.c
+++ b/src/main.c
@@ -43,6 +43,7 @@
#define HPF_ALPHA 2 /* 2 */
#define IIR_ON 0
#define SPEED 3
+#define PRIME_DELTA 1
#define SLEEP_US 16666
@@ -373,6 +374,22 @@ inline static __unused float angle_diff(float angle1, float angle2)
return diff;
}
+static __unused bool is_prime_or_one(int n)
+{
+ if (n == 1 || n == 2 || n == 3)
+ return true;
+
+ if (n <= 1 || n % 2 == 0 || n % 3 == 0)
+ return false;
+
+ for (int i = 5; i * i <= n; i += 6) {
+ if (n % i == 0 || n % (i + 2) == 0)
+ return false;
+ }
+
+ return true;
+}
+
static void rf_rx(void)
{
unsigned assi0 = 0, assi1 = 0, assi2 = 0;
@@ -455,9 +472,15 @@ static void rf_rx(void)
int acceptable_deviation = delta_watermark / 16 + 1;
if (delta < (delta_watermark - acceptable_deviation)) {
- delta_watermark--;
+#if PRIME_DELTA
+ while (!is_prime_or_one(--delta_watermark))
+ ;
+#endif
} else if (delta > (delta_watermark + acceptable_deviation)) {
- delta_watermark++;
+#if PRIME_DELTA
+ while (!is_prime_or_one(++delta_watermark))
+ ;
+#endif
}
while (delta < delta_watermark) {