Help with bit and byte addressable bitfields

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Article #121

#121

From: Ken Bass
Date: Sun, 26 Jul 1992 04:39

23 lines
1103 bytes

I'd like to know your suggestions on how to define and access a bitfield
that is both bit and byte addressable. The application is to maintain a
ram image in a memory mapped i/o system.

Lets say we have WidgetRamImg of type WidgetRamImgDef where

typedef struct {
   unsigned int bit0;
         ...
   unsigned int bit32;
} WidgetRamImgDef;

WidgetRamImgDef WidgetRamImg;

I'd like to say WidgetRamImg=0x0; at init time, but the type is wrong.
Casting to WidgetRamImgDef does not work either.

Any suggestions?

-- 
Ken Bass (kbass@gmuvax2.gmu.edu)              |   Telecommunications  
George Mason University                       |   Techniques Corp, 
Student, Department of Electrical Engineering |   Software Engineer

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Newsgroups: comp.std.c
Path: arc1-ca.pugleaf.net!sparky!uunet!haven.umd.edu!news.umbc.edu!gmuvax2!kbass
From: kbass@gmuvax2.gmu.edu (Ken Bass)
Subject: Help with bit and byte addressable bitfields
Message-ID: <1992Jul26.043900.7020@gmuvax2.gmu.edu>
Organization: George Mason University, Fairfax, Va.
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Date: Sun, 26 Jul 1992 04:39:00 GMT
Lines: 23