* Why all the SAVE_ macros in transfer_to_handler (head.S)?
@ 2000-08-08 0:36 William Kucharski
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From: William Kucharski @ 2000-08-08 0:36 UTC (permalink / raw)
To: linuxppc-embedded
This is likely a FAQ, but does anyone know of any particular reason
transfer_to_handler() (in head.S) uses the three SAVE_ macros (SAVE_4GPRS,
SAVE_8GPRs, SAVE_8GPRS) rather than just the single instruction
stmw r8,(GPR8)r21
Yeah, I know the green book says this can have greater latency and take MUCH
longer to execute than separate instructions, but I've yet to find a CPU for
which this is actually true.
So, the question stands, anyone know the original rationale? Historical
reasons? To avoid case(s) in which it is true? To avoid the POWER heritage of
the instruction? Coding style differences?
Thanks,
William Kucharski
wkucharski@lucent.com
** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/
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2000-08-08 0:36 Why all the SAVE_ macros in transfer_to_handler (head.S)? William Kucharski
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