target/hppa: Implement Fast TLB Insert instructions

These instructions are present on pcxl and pcxl2 machines,
and are used by NetBSD and OpenBSD.  See

     https://parisc.wiki.kernel.org/images-parisc/a/a9/Pcxl2_ers.pdf
     page 13-9 (195/206)

Signed-off-by: Nick Hudson <skrll@netbsd.org>
Message-Id: <20190423063621.8203-2-nick.hudson@gmx.co.uk>
[rth: Use extending loads, locally managed temporaries.]
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
diff --git a/target/hppa/insns.decode b/target/hppa/insns.decode
index 098370c..f0dd71d 100644
--- a/target/hppa/insns.decode
+++ b/target/hppa/insns.decode
@@ -133,6 +133,9 @@
 ixtlbx          000001 b:5 r:5 ... 000000 addr:1 0 00000        \
                 sp=%assemble_sr3x data=0
 
+# pcxl and pcxl2 Fast TLB Insert instructions
+ixtlbxf         000001 00000 r:5 00 0 data:1 01000 addr:1 0 00000
+
 pxtlbx          000001 b:5 x:5 sp:2 0100100 local:1 m:1 -----   data=1
 pxtlbx          000001 b:5 x:5 ... 000100 local:1 m:1 -----     \
                 sp=%assemble_sr3x data=0