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From: Carlos <carlos@cvkm.cz>
Newsgroups: comp.lang.postscript
Subject: Re: Reversing the bits in a byte
Date: Sat, 2 Dec 2017 12:46:13 +0100
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[luser droog <luser.droog@gmail.com>, 2017-12-01 21:28]
[...]
> %reverse the bits in a byte
[...]
> Now applying this new idea, which I have also explained at:
> 
>   https://codereview.stackexchange.com/a/181823/5912
> 
> I get this, which appears much simpler:
> 
> /reverse8 {
>     dup 4 bitshift exch -4 bitshift or
>     dup 16#33 and 2 bitshift exch 16#cc and -2 bitshift or
>     dup 16#55 and 1 bitshift exch 16#aa and -1 bitshift or
> } def
> 
> Exchange the two nibbles, then exchange chomps (?) in each nibble,
> then exchange the bits in each chomp. Is there any better way?

Another possibility is to use a lookup array. (I don't know which one is faster
or better.)
--