tests/tcg/s390x: Test VSTL

Add a small test to prevent regressions.

Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Message-Id: <20230804235624.263260-2-iii@linux.ibm.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>

tests/tcg/s390x/Makefile.target

@@ -59,6 +59,7 @@ Z13_TESTS=vistr
 Z13_TESTS+=lcbb
 Z13_TESTS+=locfhr
 Z13_TESTS+=vcksm
+Z13_TESTS+=vstl
 $(Z13_TESTS): CFLAGS+=-march=z13 -O2
 TESTS+=$(Z13_TESTS)
 

tests/tcg/s390x/vstl.c

@@ -0,0 +1,37 @@
+/*
+ * Test the VSTL instruction.
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+#include <assert.h>
+#include <stdlib.h>
+#include "vx.h"
+
+static inline void vstl(S390Vector *v1, void *db2, size_t r3)
+{
+    asm("vstl %[v1],%[r3],%[db2]"
+        : [db2] "=Q" (*(char *)db2)
+        : [v1] "v" (v1->v), [r3] "r" (r3)
+        : "memory");
+}
+
+int main(void)
+{
+    uint64_t buf[3] = {0x1122334455667788ULL, 0x99aabbccddeeffULL,
+                       0x5a5a5a5a5a5a5a5aULL};
+    S390Vector v = {.d[0] = 0x1234567887654321ULL,
+                    .d[1] = 0x9abcdef00fedcba9ULL};
+
+    vstl(&v, buf, 0);
+    assert(buf[0] == 0x1222334455667788ULL);
+
+    vstl(&v, buf, 1);
+    assert(buf[0] == 0x1234334455667788ULL);
+
+    vstl(&v, buf, -1);
+    assert(buf[0] == 0x1234567887654321ULL);
+    assert(buf[1] == 0x9abcdef00fedcba9ULL);
+    assert(buf[2] == 0x5a5a5a5a5a5a5a5aULL);
+
+    return EXIT_SUCCESS;
+}