Re: .../asm-i386/bitops.h performance improvements

["Richard B. Johnson" <linux-os@analogic.com>]

On Wed, 15 Jun 2005, Maciej W. Rozycki wrote:

> On Wed, 15 Jun 2005, Bodo Eggert wrote:
>
> > lea is an 8086 instruction. All clones have it in it's basic form. However,
> > the multiplicator is not documented for i486, therefore it will be a i586
> > extension.
>
> Huh?  The SIB byte has been added in the original i386 with 32-bit
> addressing.
>
>  Maciej

Well the __documented__ '486 LEA instruction doesn't
even allow the double-register indirect. It's just

	LEA r16,m
	LEA r32,m

... repeated twice

Page 26-190,  Intel486(tm) Microprocessor Programmer's Reference
Manual. ISBN 1-55512-195-4. The instruction may have been one
of those "immature features", read broken.

Cheers,
Dick Johnson
Penguin : Linux version 2.6.11.9 on an i686 machine (5537.79 BogoMips).
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