tests/tcg/s390x: Test EPSW

Add a small test to prevent regressions.

Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Message-Id: <20230704081506.276055-9-iii@linux.ibm.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>

tests/tcg/s390x/Makefile.target

@@ -36,6 +36,7 @@ TESTS+=rxsbg
 TESTS+=ex-relative-long
 TESTS+=ex-branch
 TESTS+=mxdb
+TESTS+=epsw
 
 cdsg: CFLAGS+=-pthread
 cdsg: LDFLAGS+=-pthread

tests/tcg/s390x/epsw.c

@@ -0,0 +1,23 @@
+/*
+ * Test the EPSW instruction.
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+#include <assert.h>
+#include <stdlib.h>
+
+int main(void)
+{
+    unsigned long r1 = 0x1234567887654321UL, r2 = 0x8765432112345678UL;
+
+    asm("cr %[r1],%[r2]\n"  /* cc = 1 */
+        "epsw %[r1],%[r2]"
+        : [r1] "+r" (r1), [r2] "+r" (r2) : : "cc");
+
+    /* Do not check the R and RI bits. */
+    r1 &= ~0x40000008UL;
+    assert(r1 == 0x1234567807051001UL);
+    assert(r2 == 0x8765432180000000UL);
+
+    return EXIT_SUCCESS;
+}