memcpy performance

Jonathan Larmour
Tue Dec 9 08:48:00 GMT 1997

Joel Sherrill wrote:
> An RTEMS user has noticed that the performance of the RTEMS message
> queue routines is bound by our use of newlib's memcpy routine.  The
> current implementation uses a byte-by-byte copy.
> What would it take to get a better generic implementation?  Is there one
> laying around which could be used instead?  I remember the old GNU/960
> version did some alignment and then copied 16-bytes at a time.

The current newlib implementation has this already in
et al. There is a #define PREFER_SIZE_OVER_SPEED which will use the
byte-by-byte copy if it is defined, otherwise it will use the 16-byte at
a time one.

Perhaps he has PREFER_SIZE_OVER_SPEED set?

Jonathan L.

More information about the Newlib mailing list