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From dean gaudet <d...@arctic.org>
Subject Re: [PATCH] performance fixes for number formatting
Date Thu, 19 Jul 2001 22:30:26 GMT
On Tue, 17 Jul 2001, Brian Pane wrote:

> dean gaudet wrote:
> >you might want to disassemble the functions in gdb (or using objdump) to
> >make sure that gcc emits a single division instruction for the "x / 10",
> >"x % 10" expressions -- i forget the cases where it can and can't do this.
> >the low level div instruction is a two result opcode, quotient and
> >remainder.  if it isn't doing it, then figure out how to make it do that
> >and you'll see even more improvement :)
> >
> I see one just idivl call in the output of gcc on x86.  I assume
> that means it has done the optimization, right?

yup, rad -- you should also see it use %eax (quotient) and %edx
(remainder) after the opcode.


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