What does as_add really do?

Hi,

I am using QNX 6.2 on the PXA250 (X-Scale). Can anybody tell me what the
as_add() startup library function really does? The help section on it is a
little vague.

I currently don’t have some of the internal memory mapped memory control
registers “logged” with this function; should I?

Regards,
John Roul