In that only call the HP function when the generic one fails. However,
first can you investigate the details? This sort of thing needs to be
commented.
one more note about this:
skip_prologue_using_sal() sometimes returns a pc that is past the end of
a function. after_prologue() in hppa-tdep.c checks for this explicitly
and returns 0 in this case so that we can fall back to code reading.
this can be observed e.g. with gdb.base/break.exp with the
"breakpoint small function, optimized file" test. Is this expected? or
is it a bug in skip_prologue_using_sal()?