Philip Blundell (firstname.lastname@example.org)
Mon, 19 Oct 1998 14:39:52 +0200
>Attached is a code fragment from the ppa driver modified to use parport calls
>rather than by direct IO. Direct IO limits the driver to PC style hardware,
>whereas parport calls allows for the driver to be generic for all hardware
>platforms. Your job is to adjust the C code such that the optimum assembler
>code is generated. Ideally this involves the minimum memory fetches to
>evaluate the parallel port address.
FWIW, I just compiled this fragment myself (using egcs 1.1, incidentally) and
the code looks fairly reasonable already. You can save a couple of
instructions here and there but I don't think it will make much difference in
real life -- certainly not enough to worry about at the moment. As I said, if
you have timings that show it really is a big deal then I'd be interested to
I've attached the assembler output that I get.
.ident "GCC: (GNU) egcs-2.91.57 19980901 (egcs-1.1 release)"
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This archive was generated by hypermail 2.0b3 on Wed 30 Dec 1998 - 10:18:38 EST