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[rohc] sigcomp - meaning of the F bit in the input_bit_order register



hi!

please help me to grasp the meaning of the F/H bits :-) 
in the SigComp rfc, at 8.2.  Requesting Additional Compressed Data there
is this statement:

  "When an INPUT instruction requests n bits of compressed data, it
   interprets the received bits as an integer between 0 and 2^n - 1.
   The F-bit and the H-bit specify whether the bits in these integers
   are considered to arrive in MSB to LSB order (bit set to 0) or in LSB
   to MSB order (bit set to 1)."

how should this be interpreted?

1. same as for the P bit; that is the bytes themselves are always in 
network byte order but the bits in the bytes are in LSB to MSB order when
F=1 and the other way around for F=0.

2. the bits in the _(short) integer_ are:
   
a. LSB to MSB for F=1. that would mean that the component bytes are
   also swapped which would more or less contradict another statement in
   8.2:
   "Note that the input_bit_order register cannot change the order in
   which the bytes themselves are passed to the INPUT instructions
   (bytes are always passed in the same order as they occur in the
   SigComp message)."
 
b. MSB to LSB for F=0. 

now, if 1 is the right interpretation, then wouldn't P=1 && F=1 cancel 
each other's effect?

thank you for your attention.
bye now!
cristian
-- 
 _          | There are many people who use UNIX or Linux  
(_'_        | who IMHO do not understand UNIX.
  (_'rist   |              --David Korn  
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