Add a small test to prevent regressions.

Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
---
 tests/tcg/s390x/Makefile.softmmu-target |  1 +
 tests/tcg/s390x/stpq.S                  | 20 ++++++++++++++++++++
 2 files changed, 21 insertions(+)
 create mode 100644 tests/tcg/s390x/stpq.S

diff --git a/tests/tcg/s390x/Makefile.softmmu-target b/tests/tcg/s390x/Makefile.softmmu-target
index 145e0bfde16..76345b6e643 100644
--- a/tests/tcg/s390x/Makefile.softmmu-target
+++ b/tests/tcg/s390x/Makefile.softmmu-target
@@ -27,6 +27,7 @@ ASM_TESTS =                                                                    \
     mc                                                                         \
     ssm-early                                                                  \
     stosm-early                                                                \
+    stpq                                                                       \
     unaligned-lowcore
 
 include $(S390X_SRC)/pgm-specification.mak
diff --git a/tests/tcg/s390x/stpq.S b/tests/tcg/s390x/stpq.S
new file mode 100644
index 00000000000..687a52eafa7
--- /dev/null
+++ b/tests/tcg/s390x/stpq.S
@@ -0,0 +1,20 @@
+    .org 0x200                         /* lowcore padding */
+    .globl _start
+_start:
+    lgrl %r0,value
+    lgrl %r1,value+8
+    stpq %r0,stored_value
+    clc stored_value(16),value
+    jne failure
+    lpswe success_psw
+failure:
+    lpswe failure_psw
+    .align 16
+value:
+    .quad 0x1234567887654321, 0x8765432112345678
+stored_value:
+    .quad 0, 0
+success_psw:
+    .quad 0x2000000000000,0xfff        /* see is_special_wait_psw() */
+failure_psw:
+    .quad 0x2000000000000,0            /* disabled wait */
-- 
2.41.0