back to memcpy eh?
Bert Freudenberg
bert at isg.cs.uni-magdeburg.de
Fri Dec 14 15:17:27 UTC 2001
On Fri, 14 Dec 2001, Pennell, David wrote:
> I just took a quick look at bcopy and memcpy in FreeBSD 4.1. bcopy
> is just a simple loop and memcpy is a macro that invokes bcopy.
bcopy/bzero is deprecated in glibc, they suggest memcpy/memset instead.
A comment in string.h states:
There are two kinds of optimizations:
- machine-dependent optimizations, most probably using inline
assembler code; these might be quite expensive since the code
size can increase significantly.
These optimizations are not used unless the symbol
__USE_STRING_INLINES
is defined before including this header.
- machine-independent optimizations which do not increase the
code size significantly and which optimize mainly situations
where one or more arguments are compile-time constants.
These optimizations are used always when the compiler is
taught to optimize.
See here ...
http://sources.redhat.com/cgi-bin/cvsweb.cgi/libc/string/bits/?cvsroot=glibc
http://sources.redhat.com/cgi-bin/cvsweb.cgi/libc/sysdeps/i386/bits/string.h?cvsroot=glibc
-- Bert
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