RTEMS CPU Architecture Supplement
In each of the architecture specific chapters, this subsection will detail the set of registers which are NOT preserved across subroutine invocations. The registers which are not preserved are assumed to be available for use as scratch registers. Therefore, the contents of these registers should not be assumed upon return from any RTEMS directive.
In some architectures, there may be a set of registers made available automatically as a side-effect of the subroutine invocation mechanism.
RTEMS CPU Architecture Supplement
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