Wireshark mailing list archives
Re: Why tvb_get_bits() assumes Big Endian?
From: Jaap Keuter <jaap.keuter () xs4all nl>
Date: Thu, 30 Jul 2020 13:37:57 +0200
:)
On 30 Jul 2020, at 09:19, Tomasz Moń <desowin () gmail com> wrote: On Thu, Jul 30, 2020 at 8:58 AM Tomasz Moń <desowin () gmail com <mailto:desowin () gmail com>> wrote:On Thu, Jul 30, 2020 at 8:30 AM Jaap Keuter <jaap.keuter () xs4all nl> wrote:Let’s put a hypothetical here, a 7 bit value spanning 2 octets: 15 14 13 12 11 10 9 8| 7 6 5 4 3 2 1 0 +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | | | | | | | 6| 5| 4| 3| 2| 1| 0| | | | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ This would be the typical interpretation, as seen in network protocols. Your suggestion is that the interpretation can also be: 15 14 13 12 11 10 9 8| 7 6 5 4 3 2 1 0 +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | | | | | | | 1| 0| 6| 5| 4| 3| 2| | | | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+This is not what I wanted to write. Assuming you meant two octets, and the bitmask on the 16-bit value is 0x1FC0 then the alternative interpretation would be: 15 14 13 12 11 10 9 8| 7 6 5 4 3 2 1 0 +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | | | | | | | 4| 3| 2| 1| 0| 6| 5| | | | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+Sorry, I should have displayed that in a fixed font earlier! It is perfectly clear then (the bitmask in your example is 0x03F8, and not 0x1FC0 as I was led to believe due to trying to figure it out on font not suited for the task)
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Current thread:
- Why tvb_get_bits() assumes Big Endian? Tomasz Moń (Jul 29)
- Re: Why tvb_get_bits() assumes Big Endian? Jaap Keuter (Jul 29)
- Re: Why tvb_get_bits() assumes Big Endian? Tomasz Moń (Jul 29)
- Re: Why tvb_get_bits() assumes Big Endian? Roland Knall (Jul 30)
- Re: Why tvb_get_bits() assumes Big Endian? Tomasz Moń (Jul 30)
- Re: Why tvb_get_bits() assumes Big Endian? Graham Bloice (Jul 30)
- Re: Why tvb_get_bits() assumes Big Endian? Graham Bloice (Jul 30)
- Re: Why tvb_get_bits() assumes Big Endian? Jaap Keuter (Jul 30)
- Re: Why tvb_get_bits() assumes Big Endian? Tomasz Moń (Jul 29)
- Re: Why tvb_get_bits() assumes Big Endian? Jaap Keuter (Jul 29)
- Re: Why tvb_get_bits() assumes Big Endian? Tomasz Moń (Jul 30)
- Re: Why tvb_get_bits() assumes Big Endian? Jaap Keuter (Jul 30)
- Re: Why tvb_get_bits() assumes Big Endian? Tomasz Moń (Jul 30)
- Re: Why tvb_get_bits() assumes Big Endian? Filipe Laíns (Jul 30)
- Re: Why tvb_get_bits() assumes Big Endian? Tomasz Moń (Jul 30)
- Re: Why tvb_get_bits() assumes Big Endian? John Thacker (Jul 30)