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[gpsd-dev] test_nmea2000 fail on some AIS frames
From: |
address@hidden |
Subject: |
[gpsd-dev] test_nmea2000 fail on some AIS frames |
Date: |
Fri, 30 Jan 2015 16:43:29 +0100 |
Hallo,
i have isolated to probem.
1.) I only see the problen on Intel 32 bit machine, i do not see it on ARM (i
have only 32 bit machines) and PowerPC 64 or 32 bit machines.
2.) The "wrong" values have an offset of 1 bit, so this is a rounding problem.
3.) I can fix it by forcing the constant, that i use to scale the integer taken
from nmea2000 datastream, to be a double (use .06L instead of .06)
I prefer to do this, but ask: Is the minimal increase in precision on one
platform worth the performance penalty?
In a longer term, i will check, if multiplying with a 64 bit constant and then
shifting right by 32 is the better solution to use the more intuitive floating
constants.
Your options are welcome.
Reinhard
- [gpsd-dev] test_nmea2000 fail on some AIS frames,
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