From: Mikael Pettersson <mikpe@csd.uu.se>
To: Bodo Eggert <7eggert@gmx.de>
Cc: "Maciej W. Rozycki" <macro@linux-mips.org>,
"Richard B. Johnson" <linux-os@analogic.com>,
Gene Heskett <gene.heskett@verizon.net>,
cutaway@bellsouth.net, linux-kernel@vger.kernel.org
Subject: Re: .../asm-i386/bitops.h performance improvements
Date: Thu, 16 Jun 2005 09:10:09 +0200 [thread overview]
Message-ID: <17073.9681.911274.644554@alkaid.it.uu.se> (raw)
In-Reply-To: <Pine.LNX.4.58.0506152053010.3184@be1.lrz>
Bodo Eggert writes:
> My documentation says:
>
> lea reg16, mem
> Available on 8086, 80186, 80286, 80386, 80486
> 32-bit-extension available
> Opcode: 8D mod reg r/m
>
> reg will be the target register (AX .. DI), and mod and r/m will select
> something like a direct address, a register or a combination like
> BP+DI+ofs (I won't copy the table). A multiplier is not mentioned there.
You're looking at the wrong parts of the documentation. The 16-bit
mode ModR/M doesn't have SIB, but the 32-bit mode does. The SIB includes
the scaled index. All IA32 processors have it. The only LEA-related
quirk is that its ModR/M must not describe a non-memory operand.
next prev parent reply other threads:[~2005-06-16 7:10 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <4fB8l-73q-9@gated-at.bofh.it>
[not found] ` <4fF2j-1Lo-19@gated-at.bofh.it>
2005-06-15 14:57 ` Bodo Eggert
2005-06-15 15:30 ` Maciej W. Rozycki
2005-06-15 16:06 ` Richard B. Johnson
2005-06-15 16:29 ` Maciej W. Rozycki
2005-06-15 19:10 ` Bodo Eggert
2005-06-16 3:26 ` Stephen Rothwell
2005-06-16 7:10 ` Mikael Pettersson [this message]
2005-06-15 23:53 ` cutaway
2005-06-15 8:53 cutaway
2005-06-15 12:18 ` Gene Heskett
2005-06-15 13:06 ` Richard B. Johnson
2005-06-15 19:18 ` cutaway
2005-06-15 15:34 ` Maciej W. Rozycki
2005-06-15 23:48 ` cutaway
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