[rtems commit] sparc: Document register g7 usage

[Sebastian Huber]

Module:    rtems
Branch:    master
Commit:    3fe1e4308a8d6586ab28c0c31422d0a330bf05ad
Changeset: http://git.rtems.org/rtems/commit/?id=3fe1e4308a8d6586ab28c0c31422d0a330bf05ad

Author:    Sebastian Huber <sebastian.huber at embedded-brains.de>
Date:      Tue Apr 22 10:40:26 2014 +0200

sparc: Document register g7 usage

---

 doc/cpu_supplement/sparc.t |    3 +++
 1 files changed, 3 insertions(+), 0 deletions(-)

diff --git a/doc/cpu_supplement/sparc.t b/doc/cpu_supplement/sparc.t
index 320c250..a6862c8 100644
--- a/doc/cpu_supplement/sparc.t
+++ b/doc/cpu_supplement/sparc.t
@@ -401,6 +401,9 @@ The registers g2 through g4 are reserved for applications.  GCC uses them as
 volatile registers by default.  So they are treated like volatile registers in
 RTEMS as well.
 
+The register g7 is reserved for the operating system and contains the thread
+pointer used for thread-local storage (TLS) as mandated by the SPARC ABI.
+
 @subsubsection Floating Point Registers
 
 The SPARC V7 architecture includes thirty-two,