arm-elf-gcc memcpy builtin?

Grant Edwards grante@visi.com
Tue Nov 5 07:48:00 GMT 2002


On Tue, Nov 05, 2002 at 10:10:24AM +0000, Richard Earnshaw wrote:

> > Does the ARM back end not know how to do a built-in memcpy?
> > 
> > $ arm-elf-gcc -v
> > Reading specs from /usr/local/lib/gcc-lib/arm-elf/2.95.2/specs
> > gcc version 2.95.2 19991024 (release)
> 
> The built-in memcpy will only be used if both the memory areas are word 
> aligned and the transfer is less than 65 bytes.  It doesn't have to be a 
> multiple of 4 bytes transferred.

Ah.  Most of the memcpy() calls I'm worried about have
alignments that can't be determined at compile time, so I guess
I'm out of luck.

The next option is to re-write the memcpy function in assembly
and tweak every last bit of performance out of it I can.

-- 
Grant Edwards
grante@visi.com

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