Hi,


The other end is a PC and a PIC with CCS C. I know
of the difference between the IEEE754 (PC) and the
PIC floating point format. The difference here is just
that the sign bit is in a different location. However, the
bitpattern I see on this processor has nothing in
common with what I get on the Pic. It's not just BE/LE.

Two examples:

float 6.0 on PIC:               81 40 00 00
float 6.0 on A186:      00 00 C0 40

And:

float 2.0 on PIC:               80 00 00 00
float 2.0 on A186:      00 00 00 1F

This has some similarity. However:

float 0.1 on PIC:               7B 4C CC CD
float 0.1 on A186:      9B CC CC 9D

Any patterns? More samples can be constructed on
demand.

Communication is working correct on 8 bits. It's over
serial, CAN and TCP/UDP, so no control characters
there. The format I want it in is the following (from
low to high):

8 bit exponent with bias of 7F
1 sign bit
23 bit mantissa

Now, I know some FP manipulations, but I can't seem
to get this one.


Regards,
Claudio

-----Oorspronkelijk bericht-----
Van: pic microcontroller discussion list
[mailto:PICLIST@MITVMA.MIT.EDU]Namens Jim
Verzonden: zaterdag 24 augustus 2002 21:58
Aan: PICLIST@MITVMA.MIT.EDU
Onderwerp: Re: [OT]: Floating point formats


Big Endian/Little Endian problem perhaps?

What kind of processor is on the other end
of this comm link?

Is the comm link doing a full eight bits - does
it perhaps recognize any particular control
characters that the data could represent?

What format does the characteristic and the mantissa
(of the FP number) take?

RF (and software) Jim

    "Our ability to manufacture fraud has exceeded
     our  ability to detect it."

     - Al Pacino as Viktor Taransky in the movie 'Simone'

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