Code compatibility between separately compiled and assembled modules
By writing code that adheres to the ARM Architecture Procedure Call Standard (AAPCS), you can ensure that separately compiled and assembled modules can work together.
The AAPCS forms part of the Base Standard Application Binary Interface for the ARM Architecture specification.
Interworking qualifiers associated with the
command-line option control interworking. Position independence
qualifiers, also associated with the
--apcs compiler command-line
option, control position independence, and affect the creation of
reentrant and thread-safe code.
This does not mean that you must use the same
options to get your modules to work together. You must be familiar
with the AAPCS.