From: Avi Kivity <avi@qumranet.com>
To: Mohammed Gamal <m.gamal005@gmail.com>
Cc: Guillaume Thouvenin <guillaume.thouvenin@ext.bull.net>,
kvm@vger.kernel.org
Subject: Re: [PATCH] x86 emulator: Add call near absolute instruction (group5: opcode 0xff mod r/m 2)
Date: Wed, 10 Sep 2008 10:29:44 +0300 [thread overview]
Message-ID: <48C77768.8050001@qumranet.com> (raw)
In-Reply-To: <52d4a3890809091005y6291d3e8sc8bd5b151255b002@mail.gmail.com>
Mohammed Gamal wrote:
>>
>> SrcAcc would remove the need for this change.
>>
>>
>
> Stupid question: What does Acc stand for? :)
>
Accumulator (al/ax/eax/rax). In the good old days cpus would have only
one register that was able to fully participate in arithmetic
operations, typically called A for Accumulator. The x86 retains this
tradition by having special, shorter encodings for the A register (like
the cmp opcode), and even some instructions that only operate on A (like
mul).
SrcAcc and DstAcc would accommodate these instructions by decoding A
into the corresponding 'struct operand'.
--
I have a truly marvellous patch that fixes the bug which this
signature is too narrow to contain.
next prev parent reply other threads:[~2008-09-10 7:29 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-09-08 18:47 [PATCH] x86 emulator: Add call near absolute instruction (group5: opcode 0xff mod r/m 2) Mohammed Gamal
2008-09-09 7:16 ` Guillaume Thouvenin
2008-09-09 12:49 ` Mohammed Gamal
2008-09-10 9:31 ` Guillaume Thouvenin
2008-09-09 14:51 ` Avi Kivity
2008-09-09 17:05 ` Mohammed Gamal
2008-09-10 7:29 ` Avi Kivity [this message]
2008-09-12 7:40 ` Guillaume Thouvenin
2008-09-12 10:42 ` Mohammed Gamal
2008-09-10 15:31 ` Avi Kivity
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