Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]


Groups > comp.lang.python > #75498 > unrolled thread

Creating a 2s compliment hex string for negitive numbers

Started bybSneddon <w.g.sneddon@gmail.com>
First post2014-08-01 13:35 -0700
Last post2014-08-01 14:25 -0700
Articles 3 — 2 participants

Back to article view | Back to comp.lang.python


Contents

  Creating a 2s compliment hex string for negitive numbers bSneddon <w.g.sneddon@gmail.com> - 2014-08-01 13:35 -0700
    Re: Creating a 2s compliment hex string for negitive numbers MRAB <python@mrabarnett.plus.com> - 2014-08-01 21:47 +0100
      Re: Creating a 2s compliment hex string for negitive numbers bSneddon <w.g.sneddon@gmail.com> - 2014-08-01 14:25 -0700

#75498 — Creating a 2s compliment hex string for negitive numbers

FrombSneddon <w.g.sneddon@gmail.com>
Date2014-08-01 13:35 -0700
SubjectCreating a 2s compliment hex string for negitive numbers
Message-ID<17160115-a77f-436a-837c-cd2039a7c53f@googlegroups.com>
I need to calculate an error correction code for an old protocol.

I calculate the integer 4617 and want to code the 2s compliment in ASCII
hex EDF7.  When issue the following.
>>> hex(-4617)
'-0x1209'   

Does anyone know a clean way to get to the desired results?   My ECC will always
be 16 bit (4 nibble) hex number.

Bill

[toc] | [next] | [standalone]


#75499

FromMRAB <python@mrabarnett.plus.com>
Date2014-08-01 21:47 +0100
Message-ID<mailman.12523.1406926051.18130.python-list@python.org>
In reply to#75498
On 2014-08-01 21:35, bSneddon wrote:
> I need to calculate an error correction code for an old protocol.
>
> I calculate the integer 4617 and want to code the 2s compliment in ASCII
> hex EDF7.  When issue the following.
>>>> hex(-4617)
> '-0x1209'
>
> Does anyone know a clean way to get to the desired results?   My ECC will always
> be 16 bit (4 nibble) hex number.
>
Use a bitwise AND:

 >>> hex(-4617 & 0xFFFF)
'0xedf7'

[toc] | [prev] | [next] | [standalone]


#75501

FrombSneddon <w.g.sneddon@gmail.com>
Date2014-08-01 14:25 -0700
Message-ID<f69f7aca-c744-452b-bbaa-e21699e42b5d@googlegroups.com>
In reply to#75499
On Friday, August 1, 2014 4:47:20 PM UTC-4, MRAB wrote:
> On 2014-08-01 21:35, bSneddon wrote:
> 
> > I need to calculate an error correction code for an old protocol.
> 
> >
> 
> > I calculate the integer 4617 and want to code the 2s compliment in ASCII
> 
> > hex EDF7.  When issue the following.
> 
> >>>> hex(-4617)
> 
> > '-0x1209'
> 
> >
> 
> > Does anyone know a clean way to get to the desired results?   My ECC will always
> 
> > be 16 bit (4 nibble) hex number.
> 
> >
> 
> Use a bitwise AND:
> 
> 
> 
>  >>> hex(-4617 & 0xFFFF)
> 
> '0xedf7'

Thanks

[toc] | [prev] | [standalone]


Back to top | Article view | comp.lang.python


csiph-web