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From: Eric Sosman <esos...@ieee-dot-org.invalid>
Newsgroups: comp.lang.c,comp.arch
Subject: Re: size test
Date: Wed, 25 Apr 2012 21:03:51 -0400
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On 4/25/2012 7:34 PM, Joe keane wrote:
>[...]
> #define CLASS_SIZE(X, Y) \
> ((0x4 | (Y)&  0x3)<<  (X))
>
> How do i get an inverse of CLASS_SIZE.

     It's not invertible, because it's many-to-one.  For example,
CLASS_SIZE(1,3) and CLASS_SIZE(1,127) both expand to expressions
that evaluate to 14.  Given the 14, you can't tell whether it came
from 1,3 or 1,127 (or 1,63, or ...).

-- 
Eric Sosman
esos...@ieee-dot-org.invalid