Filter
Top Products
Directives Reference
7-66 Copyright © 2000, 2001 ARM Limited. All rights reserved. ARM DUI 0068B
7.7.18 REQUIRE8 and PRESERVE8
The
REQUIRE8
directive specifies that the current file requires 8-byte alignment of the
stack.
The
PRESERVE8
directive specifies that the current file preserves 8-byte alignment of the
stack.
Syntax
REQUIRE8
PRESERVE8
Usage
LDRD
and
STRD
instructions (double-word transfers) only work correctly if the address
they access is 8-byte aligned.
If your code includes
LDRD
or
STRD
transfers to or from the stack, use
REQUIRE8
to instruct
the linker to ensure that your code is only called from objects that preserve 8-byte
alignment of the stack.
If your code preserves 8-byte alignment of the stack, use
PRESERVE8
to inform the linker.
The linker ensures that any code that requires 8-byte alignment of the stack is only
called, directly or indirectly, by code that preserves 8-byte alignment of the stack.