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Re: [PATCH] X86: Disassemble primary opcode map's group 2 ModRM.reg == 6 aliases correctly
On Mon, May 29, 2017 at 2:57 PM, Borislav Petkov <bp@suse.de> wrote:
> On Mon, May 29, 2017 at 02:52:32PM -0700, H.J. Lu wrote:
>> On Mon, May 29, 2017 at 2:49 PM, Borislav Petkov <bp@suse.de> wrote:
>> > On Mon, May 29, 2017 at 02:44:12PM -0700, H.J. Lu wrote:
>> >> Can you write some tests to verify it?
>> >
>> > Verify what exactly?
>>
>> It is SAL not SHL.
>
> There's no difference between SAL and SHL as doing an arithmetic shift
> left and a logical shift left is the same thing - in both cases the LSB
> is filled with 0.
From IA SDM:
The CF flag contains the value of the last bit shifted out of the
destination operand; it is undefined for SHL and SHR
instructions where the count is greater than or equal to the size (in
bits) of the destination operand. The OF flag is
affected only for 1-bit shifts (see “Description” above); otherwise,
it is undefined. The SF, ZF, and PF flags are set
according to the result. If the count is 0, the flags are not
affected. For a non-zero count, the AF flag is undefined.
What does AMD manual say?
--
H.J.