[wdmaudiodev] Re: How to allocate memory aligned to some spec ific value...
- From: "Moebius, V." <VMoebius@xxxxxxxxxxxxx>
- To: "'wdmaudiodev@xxxxxxxxxxxxx'" <wdmaudiodev@xxxxxxxxxxxxx>
- Date: Fri, 9 Jan 2004 11:08:26 +0100
In kernel mode you would use the ExAllocatePoolXxx functions. These have
already some restrictions in memory alignment, which could meet your
requirements possibly, e.g. allocations >= PAGE_SIZE are PAGE_SIZE aligned.
Refer to the DDK documentation for details.
Regards
Volker
> -----Original Message-----
> From: wdmaudiodev-bounce@xxxxxxxxxxxxx
> [mailto:wdmaudiodev-bounce@xxxxxxxxxxxxx]On Behalf Of Nitin Porwal,
> Noida
> Sent: Friday, January 09, 2004 10:44 AM
> To: wdmaudiodev@xxxxxxxxxxxxx
> Subject: [wdmaudiodev] Re: How to allocate memory aligned to some spec
> ific value...
>
>
> Hi,
> Thanks for your reply. I knew this solution, is this
> the only way to
> get the aligned memory. Because there is a huge wastage of
> memory in this
> approach. I want to align some of the memory in my driver to
> 2KB. in that
> case the wastage of memory will be so huge.
> If anybody know any other solution to this problem please let me
> know...
>
> Thanks
> Nitin
>
> -----Original Message-----
> From: wdmaudiodev-bounce@xxxxxxxxxxxxx
> [mailto:wdmaudiodev-bounce@xxxxxxxxxxxxx]On Behalf Of Sam Tertzakian
> Sent: Friday, January 09, 2004 1:35 PM
> To: wdmaudiodev@xxxxxxxxxxxxx
> Subject: [wdmaudiodev] Re: How to allocate memory aligned to
> some specific
> value...
>
>
> Can you do something like this:
>
> actual_ptr = alloc( desired_amt + desired_alignment );
> work_ptr = actual_ptr - ( actual_ptr % desired_alignment ) +
> desired_alignment;
> // work_ptr is aligned now to desired alignment
>
> ...now use work_ptr...
>
> then,
>
> free( actual_ptr ) // not work_ptr...need to keep actual_ptr
> until free
>
> example:
>
> i want 100 bytes aligned on 64-byte boundry (all numbers decimal)
>
> actual_ptr = alloc( 100 + 64 ); //os returns 1324
> // 1324 % 64 = 44...
> work_ptr = 1324 - 44 + 64 = 1344
> // 1344 % 64 = 0...it is aligned on 64-byte boundry
> // 1344 + 100 = 1444...we allocated 164 bytes starting at
> 1324 so there is
> enough space
>
> I think that will work and it does not rely on any specific
> APIs. It wastes
> a bit of memory, however.
>
> 1
>
>
> Hi All,
> I am new to device driver development area. I have a very basic
> question. I need to allocate memory in my driver which should
> be aligned to
> 64 bytes or 2KB or some other value. I want to know that is
> there any API
> available in DDK by which i can allocate memory aligned to a
> specific value,
> if not then what is the other way to achieve it.
>
> Waiting for response
> Thanks
> Nitin
> ******************
>
> WDMAUDIODEV addresses:
> Post message: mailto:wdmaudiodev@xxxxxxxxxxxxx
> Subscribe:
> mailto:wdmaudiodev-request@xxxxxxxxxxxxx?subject=subscribe
> Unsubscribe:
> mailto:wdmaudiodev-request@xxxxxxxxxxxxx?subject=unsubscribe
> Moderator: mailto:wdmaudiodev-moderators@xxxxxxxxxxxxx
>
> URL to WDMAUDIODEV page:
> http://www.wdmaudiodev.de/
>
> _________________________________________________________________
> Check your PC for viruses with the FREE McAfee online computer scan.
> http://clinic.mcafee.com/clinic/ibuy/campaign.asp?cid=3963
>
> ******************
>
> WDMAUDIODEV addresses:
> Post message: mailto:wdmaudiodev@xxxxxxxxxxxxx
> Subscribe:
> mailto:wdmaudiodev-request@xxxxxxxxxxxxx?subject=subscribe
> Unsubscribe:
> mailto:wdmaudiodev-request@xxxxxxxxxxxxx?subject=unsubscribe
> Moderator: mailto:wdmaudiodev-moderators@xxxxxxxxxxxxx
>
> URL to WDMAUDIODEV page:
> http://www.wdmaudiodev.de/
> ******************
>
> WDMAUDIODEV addresses:
> Post message: mailto:wdmaudiodev@xxxxxxxxxxxxx
> Subscribe:
> mailto:wdmaudiodev-request@xxxxxxxxxxxxx?subject=subscribe
> Unsubscribe:
> mailto:wdmaudiodev-request@xxxxxxxxxxxxx?subject=unsubscribe
> Moderator: mailto:wdmaudiodev-moderators@xxxxxxxxxxxxx
>
> URL to WDMAUDIODEV page:
> http://www.wdmaudiodev.de/
>
******************
WDMAUDIODEV addresses:
Post message: mailto:wdmaudiodev@xxxxxxxxxxxxx
Subscribe: mailto:wdmaudiodev-request@xxxxxxxxxxxxx?subject=subscribe
Unsubscribe: mailto:wdmaudiodev-request@xxxxxxxxxxxxx?subject=unsubscribe
Moderator: mailto:wdmaudiodev-moderators@xxxxxxxxxxxxx
URL to WDMAUDIODEV page:
http://www.wdmaudiodev.de/
Other related posts:
- » [wdmaudiodev] Re: How to allocate memory aligned to some spec ific value...
