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D - Idea: Bit clear

reply "chris" <news flak.clara.co.uk> writes:
We can already set specific bits with a single operator so i think it would be a
nice feature to be able to clear them with a single operator. Eg somthing
like...

val = val  !!  7;

would be much clearer than either of...

val = (val | 7) ^ 7;
val = val & (!7);

I am not even sure !7 actualy be converted to the correct bit mask anyway? Is
the compiler smart enough to make the bitmask the same width as the variable? At
least it does not seem obvious what width the !7 should be.

With a bit clear operator it is explicit what width the bitmask should be.

And it may be of benefit for processors (like the StrongArm) that have a bit
clear instruction. Mabey even x86 will some day.

cheers,

chris
Apr 23 2004
next sibling parent reply Juan C <Juan_member pathlink.com> writes:
<snip>
We can already set specific bits with a single operator so i think it would be a
nice feature to be able to clear them with a single operator. Eg somthing

Oh no, not more operators! Have you read up on Intrinsic Functions? Were it not for those I'd suggest adding member functions int.BitTest(int), int.BitSet(int), and int.BitClear(int) -- but they would make it difficult to mimic x = y op z
Apr 23 2004
parent "chris" <news flak.clara.co.uk> writes:
"Juan C" <Juan_member pathlink.com> wrote in message
news:c6cgog$2qlh$1 digitaldaemon.com...
 <snip>
We can already set specific bits with a single operator so i think it would


nice feature to be able to clear them with a single operator. Eg somthing

Oh no, not more operators! Have you read up on Intrinsic Functions?

I didnt know about those but from the docs it seems the only functions are for setting / clearing single bits by index. cheers, chris
Apr 24 2004
prev sibling parent reply "Vathix" <vathix dprogramming.com> writes:
From: "chris" <news flak.clara.co.uk>

 We can already set specific bits with a single operator so i think it

 nice feature to be able to clear them with a single operator. Eg somthing
 like...

val &= ~7;
Apr 22 2004
parent reply "chris" <news flak.clara.co.uk> writes:
"Vathix" <vathix dprogramming.com> wrote in message
news:c6cgp3$2qlt$1 digitaldaemon.com...
 From: "chris" <news flak.clara.co.uk>

 We can already set specific bits with a single operator so i think it

 nice feature to be able to clear them with a single operator. Eg somthing
 like...

val &= ~7;

what does "~" do? It is listed under "Add Expresions" but i still dont follow what it does. cheers, chris
Apr 24 2004
next sibling parent reply Lars Ivar Igesund <larsivar igesund.net> writes:
chris wrote:
 
 what does "~" do? It is listed under "Add Expresions" but i still dont follow
 what it does.

Array concatenation (and thus also string concatenation). Lars Ivar
Apr 24 2004
parent reply "chris" <news flak.clara.co.uk> writes:
"Lars Ivar Igesund" <larsivar igesund.net> wrote in message
news:c6dm4f$281$1 digitaldaemon.com...
 chris wrote:
 what does "~" do? It is listed under "Add Expresions" but i still dont


 what it does.

Array concatenation (and thus also string concatenation).

i am confused.... so what does his example do? Ie... val &= ~7; chris
Apr 24 2004
parent reply Dave Sieber <dsieber spamnot.sbcglobal.net> writes:
"chris" <news flak.clara.co.uk> wrote:

 i am confused.... so what does his example do? Ie...
 
 val &= ~7;

When used as a unary operator, '~' is bit-wise NOT, whereas '!' is a unary logical NOT. Same as in C and C++. -- dave
Apr 24 2004
parent "chris" <news flak.clara.co.uk> writes:
"Dave Sieber" <dsieber spamnot.sbcglobal.net> wrote in message
news:Xns94D53C42924D8dsiebersbc 63.105.9.61...
 "chris" <news flak.clara.co.uk> wrote:

 i am confused.... so what does his example do? Ie...

 val &= ~7;

When used as a unary operator, '~' is bit-wise NOT, whereas '!' is a unary logical NOT. Same as in C and C++.

ah, makes sense now. Cheers. It is not listed in the "Bitwise Epresions" docs btw. chris
Apr 24 2004
prev sibling parent "Matthew" <matthew.hat stlsoft.dot.org> writes:
~ is unary bitwise not

"chris" <news flak.clara.co.uk> wrote in message
news:c6dltq$254$1 digitaldaemon.com...
 "Vathix" <vathix dprogramming.com> wrote in message
 news:c6cgp3$2qlt$1 digitaldaemon.com...
 From: "chris" <news flak.clara.co.uk>

 We can already set specific bits with a single operator so i think it

 nice feature to be able to clear them with a single operator. Eg somthing
 like...

val &= ~7;

what does "~" do? It is listed under "Add Expresions" but i still dont follow what it does. cheers, chris

Apr 24 2004