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Decomposing a bit field? [message #71716]

Wed, 21 July 2010 02:40

rjp23
Messages: 97
Registered: June 2010

Member

Hi all,

I have some data that is contained within a 32-bit field.

I'm using some code from a colleague which seems to almost do what I
want but not quite.

An example of one of the data values is 15982561

The following code takes this and creates an array of 1s and 0s for
whether each bit is set or not.

test=intarr(32)
for i=0, 31 do begin test[i]=(ISHFT((15982561),-i) AND 1B)

However, for example bits 1-4 need to be combined (and contain data
from 0-15). As I don't quite understand what the code above is doing
I'm not sure how to (or if it can be) modified to not just operate on
the individual bits but on groups of bits.

What I need to extract is the information in the folowing form:

Bit 0: 0 or 1
Bits 1-4: 0-15
Bit 5: 0 or 1
Bits 6-8: 0-8
etc

Thanks in advance

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[Message index]

		Decomposing a bit field? By: rjp23 on Wed, 21 July 2010 02:40
		Re: Decomposing a bit field? By: Chris[6] on Wed, 21 July 2010 15:41
		Re: Decomposing a bit field? By: penteado on Wed, 21 July 2010 09:21
		Re: Decomposing a bit field? By: David Fanning on Wed, 21 July 2010 09:09
		Re: Decomposing a bit field? By: Steve[5] on Wed, 21 July 2010 09:04
		Re: Decomposing a bit field? By: rjp23 on Wed, 21 July 2010 04:25
		Re: Decomposing a bit field? By: Chris[6] on Wed, 21 July 2010 03:33
		Re: Decomposing a bit field? By: greg.addr on Wed, 21 July 2010 03:31
		Re: Decomposing a bit field? By: Steve[5] on Wed, 21 July 2010 03:29

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