[PATCH] [PowerPC] Document requirements for VSX feature

[Pedro Franco de Carvalho <pedromfc@linux.ibm.com>]

As suggested in
https://sourceware.org/ml/gdb-patches/2018-10/msg00510.html, this
patch changes the documentation for the VSX tdesc feature to make it
clear that the altivec and FPU features are requirements.

gdb/doc/ChangeLog:
YYYY-MM-DD  Pedro Franco de Carvalho  <pedromfc@linux.ibm.com>

	* gdb.texinfo: Document the altivec and fpu requirements for
	the org.gnu.gdb.power.vsx feature.
---
 gdb/doc/gdb.texinfo | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo
index 9756155a39..944a2c4383 100644
--- a/gdb/doc/gdb.texinfo
+++ b/gdb/doc/gdb.texinfo
@@ -43230,11 +43230,13 @@ contain registers @samp{vr0} through @samp{vr31}, @samp{vscr},
 and @samp{vrsave}.
 
 The @samp{org.gnu.gdb.power.vsx} feature is optional.  It should
-contain registers @samp{vs0h} through @samp{vs31h}.  @value{GDBN}
-will combine these registers with the floating point registers
-(@samp{f0} through @samp{f31}) and the altivec registers (@samp{vr0}
-through @samp{vr31}) to present the 128-bit wide registers @samp{vs0}
-through @samp{vs63}, the set of vector registers for POWER7.
+contain registers @samp{vs0h} through @samp{vs31h}.  @value{GDBN} will
+combine these registers with the floating point registers (@samp{f0}
+through @samp{f31}) and the altivec registers (@samp{vr0} through
+@samp{vr31}) to present the 128-bit wide registers @samp{vs0} through
+@samp{vs63}, the set of vector-scalar registers for POWER7.
+Therefore, this feature requires both @samp{org.gnu.gdb.power.fpu} and
+@samp{org.gnu.gdb.power.altivec}.
 
 The @samp{org.gnu.gdb.power.spe} feature is optional.  It should
 contain registers @samp{ev0h} through @samp{ev31h}, @samp{acc}, and
-- 
2.13.6