[gpsd-dev] test_nmea2000 fail on some AIS frames

[address@hidden]

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