Messages in this thread | | | Date | Mon, 7 Dec 1998 18:41:52 -0800 | From | Richard Henderson <> | Subject | Re: Problem with 1G RAM |
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On Sat, Dec 05, 1998 at 09:48:44PM +0100, MOLNAR Ingo wrote: > on x86, we can do instructions like: > > movl 0xc0000028(%eax), %ebx > > the compiler expands it's patters wildly differently when it's a constant.
Um, have you tried this Ingo? Given
extern char __foo; #define foo ((int)&__foo) int bar(int *x) { return x[foo+45]; }
or suchlike you should see __foo combined with other operations.
movl $__foo+45,%eax movl (%edx,%eax,4),%eax
in this case due to the shift.
My guess is that you can do fairly well with the immediates. Certainly better than having them be completely variable.
r~
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