Lpc2000

Which compiler are you using?

Try this instead:

ptr = (unsigned char *)(((unsigned long)ptr) & 0xFFC0);

that's because when dealing with pointers, the + operator increments by the 
size of the object being pointed to.

unsigned long ptr;

ptr++; adds 4 to the value of pointer.

casting the pointer to a number allows you to do your binary manipulation, 
then cast it back to a pointer.

For you alignment question, check this out:

http://gcc.gnu.org/onlinedocs/gcc/Type-Attributes.html

-- Sean

At 19:06 2/6/2006, you wrote:
>Hello,
>
>I have been doing assembly so long, that I am having trouble with
>my C program.
>
>I have records of 64 bytes in length, and the start of the record area
>must start on an even 0x0100 boundary in ram.
>
>In assembly, doing tests on the pointer for being in the middle of a
>record, or to jump to the next record is a piece of cake.
>
>assuming:
>unsigned char data[2048]; is aligned on an even boundary
>unsigned char *ptr;
>#define RECORD_SIZE 64
>#define INCREMENT_MASK 0xffc0
>#define LINE_MASK 0x3f            //record_size -1
>
>       ptr = data;
>       ....
>the compiler hates:
>       ptr &= INCREMENT_MASK;      // in case we are in the middle of a rec
>but tolerates this:
>       ptr += RECORD_SIZE;      //jump to the start of the next record
>
>since the ram area is 64k, i would think this would work.
>
>TIA
>
>Glen
>
>
>
>
>
>SPONSORED LINKS
><http://groups.yahoo.com/gads?t=ms&k=Microcontrollers&w1=Microcontrollers&w2=Microprocessor&w3=Intel+microprocessors&w4=Pic+microcontrollers&c=4&s=95&.sig=mfaAujKZXA2Z_vxre9sGnQ>Microcontrollers 
><http://groups.yahoo.com/gads?t=ms&k=Microprocessor&w1=Microcontrollers&w2=Microprocessor&w3=Intel+microprocessors&w4=Pic+microcontrollers&c=4&s=95&.sig=9jjd2D3GOLIESVQssLmLsA>Microprocessor 
><http://groups.yahoo.com/gads?t=ms&k=Intel+microprocessors&w1=Microcontrollers&w2=Microprocessor&w3=Intel+microprocessors&w4=Pic+microcontrollers&c=4&s=95&.sig=OMnZuqMZX95mgutt4B-tDw>Intel 
>microprocessors
><http://groups.yahoo.com/gads?t=ms&k=Pic+microcontrollers&w1=Microcontrollers&w2=Microprocessor&w3=Intel+microprocessors&w4=Pic+microcontrollers&c=4&s=95&.sig=Malspbd0T4Rq3M4Q0nHrfw>Pic 
>microcontrollers
>
>
>----------
>YAHOO! GROUPS LINKS
>
>    *  Visit your group "<http://groups.yahoo.com/group/lpc2000>lpc2000" 
> on the web.
>    *
>    *  To unsubscribe from this group, send an email to:
>    * 
> <mailto:lpc2000-unsubscribe@yahoogroups.com?subject=Unsubscribe>lpc2000-unsubscribe@yahoogroups.com 
>
>    *
>    *  Your use of Yahoo! Groups is subject to the 
> <http://docs.yahoo.com/info/terms/>Yahoo! Terms of Service.
>
>
>----------