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From adbc5a6f26b8bdaff165f3c01843e58249ad6108 Mon Sep 17 00:00:00 2001
From: Jared Boone <jboone@earfeast.com>
Date: Mon, 17 Aug 2015 11:14:14 -0700
Subject: [PATCH 51/68] Fix calculation of mag^2.
---
firmware/sgpio-rx/sgpio-rx.c | 8 ++------
1 file changed, 2 insertions(+), 6 deletions(-)
--- a/firmware/sgpio-rx/sgpio-rx.c
+++ b/firmware/sgpio-rx/sgpio-rx.c
@@ -53,7 +53,7 @@
volatile uint32_t buffer[4096];
uint32_t i = 0;
- int16_t magsq;
+ uint32_t magsq;
int8_t sigi, sigq;
sgpio_cpld_stream_enable(&sgpio_config);
@@ -68,11 +68,7 @@
/* find the magnitude squared */
sigi = buffer[i & 4095] & 0xff;
sigq = (buffer[i & 4095] >> 8) & 0xff;
- magsq = sigi * sigq;
- if ((uint16_t)magsq & 0x8000) {
- magsq ^= 0xffff;
- magsq++;
- }
+ magsq = sigi * sigi + sigq * sigq;
/* illuminate LED3 only when magsq exceeds threshold */
if (magsq > 0x3c00)
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