From f819b8d6788552263d8e56286fe8135a6b0be0f9 Mon Sep 17 00:00:00 2001
From: Michael Schwarz <m.schwarz@consolinno.de>
Date: Wed, 1 Oct 2025 14:03:50 +0200
Subject: [PATCH] Fix conversion from float to quint16 in
 SunSpecDataPoint::convertFromFloatWithSSF

Calling this function with a negative value and DataType::Int16 always gives a 0 result on ARM. Need to convert to qint16 first to avoid undefined behavior (cf. https://embeddeduse.com/2013/08/25/casting-a-negative-float-to-an-unsigned-int/)
---
 libnymea-sunspec/sunspecdatapoint.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/libnymea-sunspec/sunspecdatapoint.cpp b/libnymea-sunspec/sunspecdatapoint.cpp
index c7bfd34..d45e827 100644
--- a/libnymea-sunspec/sunspecdatapoint.cpp
+++ b/libnymea-sunspec/sunspecdatapoint.cpp
@@ -714,7 +714,7 @@ QVector<quint16> SunSpecDataPoint::convertFromFloatWithSSF(float value, qint16 s
         break;
     }
     case Int16: {
-        quint16 rawValue = static_cast<quint16>(value * pow(10, -1 * scaleFactor));
+        quint16 rawValue = static_cast<qint16>(value * pow(10, -1 * scaleFactor));
         rawData << rawValue;
         break;
     }