Paolo Bonzini wrote:
Paolo, who made the first paid computer work on Realia COBOL
well that is fun ... quite a while ago :-)
Andi Kleen wrote:
Robert Dewar <[EMAIL PROTECTED]> writes:
I must say I am a bit surprised that gcc never takes advantage
of the fact that inc and dec do not destroy the carry flag, this
is quite significant for some loops.
A lot of this old wisdom is no longer true.
inc and dec are to be g
I must say I am a bit surprised that gcc never takes advantage
of the fact that inc and dec do not destroy the carry flag, this
is quite significant for some loops.
And which is extremely bad on Pentium II and newer.
Paolo, who made the first paid computer work on Realia COBOL
Robert Dewar <[EMAIL PROTECTED]> writes:
>
> I must say I am a bit surprised that gcc never takes advantage
> of the fact that inc and dec do not destroy the carry flag, this
> is quite significant for some loops.
A lot of this old wisdom is no longer true.
inc and dec are to be generally avoide
My question: does GCC-generated code ever actually depend on this aspect
of the x86 architecture - i.e., on instructions that architecturally
change some but not all condition codes _not_ changing those bits that
they're not supposed to change?
No.
An interesting anecdote from decades ago. W
Hi Richard,
On Wednesday 26 October 2005 00:30, Richard Henderson wrote:
> On Mon, Oct 24, 2005 at 03:39:53PM -0500, Bryan Ford wrote:
> > My question: does GCC-generated code ever actually depend on this aspect
> > of the x86 architecture - i.e., on instructions that architecturally
> > change so
On Mon, Oct 24, 2005 at 03:39:53PM -0500, Bryan Ford wrote:
> My question: does GCC-generated code ever actually depend on this aspect of
> the x86 architecture - i.e., on instructions that architecturally change some
> but not all condition codes _not_ changing those bits that they're not
> sup
I have a question about GCC's handling of the condition codes (specifically
the CF, ZF, NF, OF, PF bits in bits in EFLAGS) on the i386 that will
hopefully be trivial to anyone familiar with the implementation of the i386
target. My impression is that GCC generally treats the i386 condition code
