2012-09-06 Andreas Krebbel <Andreas.Krebbel@de.ibm.com>

	* config/tc-s390.c (set_highgprs_p): New variable.
	(s390_machinemode): New function.
	(md_pseudo_table): Add new pseudo command machinemode.
	(md_parse_option): Set set_highgprs_p to TRUE if -mzarch was
	specified on command line.
	(s390_elf_final_processing): Set the highgprs flag in the ELF
	header depending on set_highgprs_p.

	* doc/c-s390.texi: Document new pseudo machinemode.

1 files changed, 13 insertions, 0 deletions

diff --git a/gas/doc/c-s390.texi b/gas/doc/c-s390.texi
index 79713277ca..76dc1449c0 100644
--- a/gas/doc/c-s390.texi
+++ b/gas/doc/c-s390.texi
@@ -873,6 +873,19 @@ restored with @code{.machine pop}.  Be aware that the cpu string has
 to be put into double quotes in case it contains characters not
 appropriate for identifiers.  So you have to write @code{"z9-109"}
 instead of just @code{z9-109}.
+
+@cindex @code{.machinemode} directive, s390
+@item .machinemode string
+This directive allows to change the architecture mode for which code
+is being generated.  @code{string} may be @code{esa}, @code{zarch},
+@code{zarch_nohighgprs}, @code{push}, or @code{pop}.
+@code{.machinemode zarch_nohighgprs} can be used to prevent the
+@code{highgprs} flag from being set in the ELF header of the output
+file.  This is useful in situations where the code is gated with a
+runtime check which makes sure that the code is only executed on
+kernels providing the @code{highgprs} feature.
+@code{.machinemode push} saves the currently selected mode, which may
+be restored with @code{.machinemode pop}.
 @end table
 
 @node s390 Floating Point