extracting front bits from an unsigned long long?

[Digital Puer]

Hi, suppose I have an unsigned long long. I would like to extract
the front 'n' bits of this value and convert them into an integer.
For example, if I extract the first 3 bits, I would get an int between
0 and 7 (=2^3-1). Could someone please help out?

I can assume the largest returned value fits in an int. Also,
I'm on a big-endian PPC (AIX), in case that matters.

Ideally, I'd like to implement a prototype like:
int extractFrontBit s(unsigned long long value, int num_bits);

[Richard Tobin]

In article <11************ **********@g14g 2000cwa.googleg roups.com>,
sl*******@yahoo .com <sl*******@gmai l.com> wrote:

Haven't had much experience with non-native english speakers have you?
In a lot of eastern languages front and first are synonyms.

They are often synonyms in English. In particular, when objects are
moving along a path, the front one will be the first one. But when
(as is the case here) the idea is of looking at a static sequence of
objects, the situation is less clear. "3" is the first digit of 315
when you read or write it, but if you imagine the sequence itself
pointing in left-to-right order (i.e. English reading order) then you
would call "5" the front digit.

In such circumstances it is better to be explicit and say "leftmost",
or if you don't even want to commit to a particular writing direction,
"most significant".

-- Richard

[Mark McIntyre]

On 12 Nov 2005 14:41:20 -0800, in comp.lang.c , "sl*******@yaho o.com"
<sl*******@gmai l.com> wrote:

Haven't had much experience with non-native english speakers have you?
No, I only worked for a French bank for 10 years. Plus let me tell
you, working in London is like working in the tower of babel..
In a lot of eastern languages front and first are synonyms.

So what?
--
Mark McIntyre
CLC FAQ <http://www.eskimo.com/~scs/C-faq/top.html>
CLC readme: <http://www.ungerhu.com/jxh/clc.welcome.txt >

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[pete]

sl*******@yahoo .com wrote:

Mark McIntyre wrote:

On 11 Nov 2005 12:08:47 -0800, in comp.lang.c , "Digital Puer"
<di**********@h otmail.com> wrote:

Just for my edification,
how else would one interpret "front bits"?
I wouldn't
I didn't.
- it doesn't mean anything to me.
Me neither.
Arrays of bits don't have backs, fronts or sides...

E.g. the front digit of 543 is 5.

First perhaps. Leftmost perhaps. Front no.

I would call that, the most significant digit.
Haven't had much experience with non-native english speakers have you?
In a lot of eastern languages front and first are synonyms.

It seemed to me, that given a choice between bit0 and bit1,
that bit0, the low order bit, would be the first one.

But I often have trouble understanding plain English,
and yes, it is my only language.

I like to code but I don't enjoy extracting specifications.
I really would have to be paid, in order to do that.

When somebody posts a question and I don't understand it right,
then I answer it wrong.

When somebody posts a question and I do understand it right,
then my chances are better.

--
pete

[Flash Gordon]

sl*******@yahoo .com wrote:

Mark McIntyre wrote:

On 11 Nov 2005 12:08:47 -0800, in comp.lang.c , "Digital Puer"
<di**********@h otmail.com> wrote:

Just for my edification, how else would one interpret "front bits"?

I wouldn't - it doesn't mean anything to me. Arrays of bits don't have
backs, fronts or sides...

E.g. the front digit of 543 is 5.

First perhaps. Leftmost perhaps. Front no.

Haven't had much experience with non-native english speakers have you?
In a lot of eastern languages front and first are synonyms.

That's as maybe, but this is not one of those eastern languages.

I would not use front or first. I would possibly use left, but generally
highest or most significant.
--
Flash Gordon
Living in interesting times.
Although my email address says spam, it is real and I read it.

[slebetman]

Mark McIntyre wrote:

On 12 Nov 2005 14:41:20 -0800, in comp.lang.c , "sl*******@yaho o.com"
<sl*******@gmai l.com> wrote:

In a lot of eastern languages front and first are synonyms.

So what?

So, to a lot of people like me, who often 'think' in our native
language and then translate into english we often say front instead of
first. In Malay for instance, first relates to chronological sequence
and front relates to spatial sequence. A sequence of bits in a register
or in memory is spatial. I'm not saying you're wrong. As in english it
IS better to use 'first'. Actually it is better to use 'most
significant'. My point is simply that not everyone thinks that way.

OK, so there was a misunderstandin g. It has been resolved. The OP is
happy. Move along now...

[Dik T. Winter]

In article <dl***********@ pc-news.cogsci.ed. ac.uk> ri*****@cogsci. ed.ac.uk (Richard Tobin) writes:

In article <11************ **********@g14g 2000cwa.googleg roups.com>,
sl*******@yahoo .com <sl*******@gmai l.com> wrote:

Haven't had much experience with non-native english speakers have you?
In a lot of eastern languages front and first are synonyms.

.... In such circumstances it is better to be explicit and say "leftmost",
or if you don't even want to commit to a particular writing direction,
"most significant".

And both do not really convey the meaning of the OP. Which was (as I
understand it now) the sequence of 'k' bits starting at the first 1 bit
in the binary representation of the number. Or (in other terms) the
first 'k' bits if leading 0's are ignored.
--
dik t. winter, cwi, kruislaan 413, 1098 sj amsterdam, nederland, [phone]
home: bovenover 215, 1025 jn amsterdam, nederland; http://www.cwi.nl/~dik/

[Mark McIntyre]

On 12 Nov 2005 16:41:19 -0800, in comp.lang.c , "sl*******@yaho o.com"
<sl*******@gmai l.com> wrote:

Mark McIntyre wrote:

On 12 Nov 2005 14:41:20 -0800, in comp.lang.c , "sl*******@yaho o.com"
<sl*******@gmai l.com> wrote:

>In a lot of eastern languages front and first are synonyms.
So what?

So, to a lot of people like me, who often 'think' in our native
language and then translate into english we often say front instead of
first.

If you cast your mind back, you'll recall that the question I was
answering was "how would you interpret front bits". Not unnaturally I
expressed my opinion of how I'd intrepret it, and what I'd call the
leftmost bit of eg 543.

It was NOT "how would you expect someone with limited grasp of English
to translate their own word for 'first' into English". So I didn't
answer this question.

So you see, I consider your comment utterly bloody irrelevant!
OK, so there was a misunderstandin g. It has been resolved.

I do hope so
--
Mark McIntyre
CLC FAQ <http://www.eskimo.com/~scs/C-faq/top.html>
CLC readme: <http://www.ungerhu.com/jxh/clc.welcome.txt >

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