Code optimization <LEA Instruction>

[Richard B. Johnson]

On Fri, 28 Jan 2000, Alan Cox wrote:

> > > > be used to change the value of an index register faster than
> > > > using the ADD instruction (Page G-10, Intel '486 Rag).
> > > 
> > > It is
> > 
> > It is not. Never was and can't possibly be. Further, tests show
> > as expected, that address generation takes more time than register
> > addition.
> 
> > > Your test is wrong. See the notes on address generation stalls
> > 
> > Yea. Sure.
> 
> Read the intel book then come back and apologise

I will not.

I state that the newer 'C' versions are using LEA abitrarily for
arithmetic on index registers.

I write a demo that clearly shows that LEA cannot be abitrarily used
for aritmetic on an index register.

You, for some unknown reason declare the demo invalid while it clearly
is designed to emphasize the problem and demonstrate it.

So back off!

Cheers,
Dick Johnson

Penguin : Linux version 2.3.39 on an i686 machine (800.63 BogoMips).


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