supported for backwards compatibility with earlier versions of the
ARM C and C++ libraries.
ARM recommends that you use
The differences between
__user_initial_stackheap()receives the stack pointer (containing the same value it had on entry to
r1, and is expected to return the new stack base in
__user_setup_stackheap()receives the stack pointer in
sp, and returns the stack base in
__user_initial_stackheap()is provided with a small temporary stack to run on. This temporary stack enables
__user_initial_stackheap()to be implemented in C, providing that it uses no more than 88 bytes of stack space.
__user_setup_stackheap()has no temporary stack and cannot usually be implemented in C.
__user_initial_steakheap() reduces code
no requirement for a temporary stack.
In the following circumstances you cannot use the provided
__user_setup_stackheap() function, but
you can use the
your implementation is sufficiently complex that it warrants the use of a temporary stack when setting up the initial heap and stack
you have a requirement to implement the heap and stack creation code in C rather than in assembly language.