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Re: What is 'mov (%r11,%rax,1),%dl'?

From: Jeff Law <law at redhat dot com>
To: Segher Boessenkool <segher at kernel dot crashing dot org>, Jeffrey Walton <noloader at gmail dot com>
Cc: "gcc-help at gcc dot gnu dot org" <gcc-help at gcc dot gnu dot org>
Date: Sat, 2 Jan 2016 09:35:01 -0700
Subject: Re: What is 'mov (%r11,%rax,1),%dl'?
Authentication-results: sourceware.org; auth=none
References: <CAH8yC8m4SFCN+OC8P2HVGEZp3CyqW8CaNXXLmZo9F2osnaZW+g at mail dot gmail dot com> <20160102160114 dot GA19518 at gate dot crashing dot org>

On 01/02/2016 09:01 AM, Segher Boessenkool wrote:

On Sat, Jan 02, 2016 at 10:01:26AM -0500, Jeffrey Walton wrote:

    0x000000010048d87b <+174>:   xor    %eax,%eax
=> 0x000000010048d87d <+176>:   mov    (%r11,%rax,1),%dl

(gdb) info registers
rax            0x9b7a   0x9b7a


Why is AX not 0 here?  That seems wrong.

Maybe there's an instruction somewhere that jumps to the movinstruction. So %eax would be zero somtimes and some other value othertimes.


jeff

Follow-Ups:
- Re: What is 'mov (%r11,%rax,1),%dl'?
  - From: Jeffrey Walton

References:
- What is 'mov (%r11,%rax,1),%dl'?
  - From: Jeffrey Walton
- Re: What is 'mov (%r11,%rax,1),%dl'?
  - From: Segher Boessenkool

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