From: Paul Brook <paul@nowt.org>
To: qemu-devel@nongnu.org
Subject: [Qemu-devel] [5619] Mention output overlaps.
Date: Tue, 04 Nov 2008 13:17:18 +0000 [thread overview]
Message-ID: <E1KxLmY-0005OP-KL@cvs.savannah.gnu.org> (raw)
Revision: 5619
http://svn.sv.gnu.org/viewvc/?view=rev&root=qemu&revision=5619
Author: pbrook
Date: 2008-11-04 13:17:17 +0000 (Tue, 04 Nov 2008)
Log Message:
-----------
Mention output overlaps.
Modified Paths:
--------------
trunk/tcg/README
Modified: trunk/tcg/README
===================================================================
--- trunk/tcg/README 2008-11-04 12:33:21 UTC (rev 5618)
+++ trunk/tcg/README 2008-11-04 13:17:17 UTC (rev 5619)
@@ -390,6 +390,11 @@
instruction. Memory constraints are not supported in this
version. Aliases are specified in the input operands as for GCC.
+The same register may be used for both an input and an output, even when
+they are not explicitly aliased. If an op expands to multiple target
+instructions then care must be taken to avoid clobbering input values.
+GCC style "early clobber" outputs are not currently supported.
+
A target can define specific register or constant constraints. If an
operation uses a constant input constraint which does not allow all
constants, it must also accept registers in order to have a fallback.
reply other threads:[~2008-11-04 13:17 UTC|newest]
Thread overview: [no followups] expand[flat|nested] mbox.gz Atom feed
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=E1KxLmY-0005OP-KL@cvs.savannah.gnu.org \
--to=paul@nowt.org \
--cc=qemu-devel@nongnu.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).