From: Marc Gauthier <marc@cadence.com>
To: Max Filippov <jcmvbkbc@gmail.com>, Pedro Alves <palves@redhat.com>
Cc: "gdb-patches@sourceware.org" <gdb-patches@sourceware.org>,
Maxim Grigoriev <maxim2405@gmail.com>,
Woody LaRue <larue@cadence.com>
Subject: RE: [PATCH] xtensa: fix access to the last pseudo register
Date: Wed, 27 May 2015 15:13:00 -0000 [thread overview]
Message-ID: <SN1PR0701MB1853132657CD4B79F2DF0F4CC3CB0@SN1PR0701MB1853.namprd07.prod.outlook.com> (raw)
In-Reply-To: <CAMo8BfKWJwReVYA84Bc+LgnCbzk4C4R7fOZbikP0NsDA0oqy6Q@mail.gmail.com>
Max Filippov wrote:
[...]
> I'm removing that aliasing to expose the last pseudoregister.
> After that patch fp pseudo register still exists and it is a read only
> alias
> for a1. I don't think that's right, because normally frame pointer is a7
> or
> a15, depending on ABI, but that's definitely a separate question.
If the compiler allocated a frame pointer for the function, it is
a7 or a15 according to ABI, correct. If no separate pointer is
allocated (usually when no variable stack allocation such as alloca
or similar is used in the function), I believe a1 is effectively
both the stack pointer and the frame pointer.
-Marc
next prev parent reply other threads:[~2015-05-27 15:13 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-05-17 23:12 Max Filippov
2015-05-27 2:11 ` Max Filippov
2015-05-27 10:16 ` Pedro Alves
2015-05-27 10:55 ` Max Filippov
2015-05-27 15:13 ` Marc Gauthier [this message]
2015-05-29 9:40 ` Pedro Alves
2015-05-29 10:36 ` Max Filippov
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