From: Helge Deller <deller@gmx.de>
To: linux-parisc@vger.kernel.org,
James Bottomley <James.Bottomley@HansenPartnership.com>
Subject: [PATCH] parisc: document the shadow registers
Date: Sat, 29 Jun 2013 13:24:16 +0200 [thread overview]
Message-ID: <20130629112416.GA1287@p100.box> (raw)
Signed-off-by: Helge Deller <deller@gmx.de>
diff --git a/Documentation/parisc/registers b/Documentation/parisc/registers
index dd3cadd..10c7d17 100644
--- a/Documentation/parisc/registers
+++ b/Documentation/parisc/registers
@@ -78,6 +78,14 @@ Shadow Registers used by interruption handler code
TOC enable bit 1
=========================================================================
+
+The PA-RISC architecture defines 7 registers as "shadow registers".
+Those are used in RETURN FROM INTERRUPTION AND RESTORE instruction to reduce
+the state save and restore time by eliminating the need for general register
+(GR) saves and restores in interruption handlers.
+Shadow registers are the GRs 1, 8, 9, 16, 17, 24, and 25.
+
+=========================================================================
Register usage notes, originally from John Marvin, with some additional
notes from Randolph Chung.
reply other threads:[~2013-06-29 11:24 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=20130629112416.GA1287@p100.box \
--to=deller@gmx.de \
--cc=James.Bottomley@HansenPartnership.com \
--cc=linux-parisc@vger.kernel.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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.