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

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