[ECOS] While use %o register as parameters in callee passed by the caller in sparc? SOS.
Gary Thomas
gthomas@ecoscentric.com
Tue Sep 17 08:09:00 GMT 2002
On Tue, 2002-09-17 at 08:37, Qiang Huang wrote:
> Hi:
> I just wondering why in the context.S the parameter passed by the caller
> to the callee routine: hal_thread_switch_context() still appears as %o,
> shouldn't that be %i in callee's register window? or are they share the same
> register window??
Exactly. The register window only changes (and hence, %oX becomes
%iX) after the execution of a "save" instruction. This is a very
special function which does not use "save" as part of it's preamble.
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