I tested the ×256 and tx.HB=/ tx.LB= methods.Tx = b1×256 +b0 is the same thing as Tx.HB = b1, Tx.LB = b0
Probably .HB / .LB method is faster and uses less memory.
I will look at it.
Anyway with 32 bit calculations you need to take care of the signed 16bit variables, which Oshonsoft can't do directly.
I think the easiest way is by converting the 16 bit T1, T2 etc.
to single variables.
×256 uses 18 instructions and .HB / .LB uses 4
I ran the calculations with the values in BMP280 datasheet in Oshonsoft simulator for the temperature
I got T=25.0824
In the datasheet T = 25.08
Seems good enough.
I will next calculate the pressure and then upload the program.