tests/tcg/s390x: Add clst.c

Add a basic test to prevent regressions.

Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Message-Id: <20221025213008.2209006-2-iii@linux.ibm.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

tests/tcg/s390x/Makefile.target

@@ -25,6 +25,7 @@ TESTS+=signals-s390x
 TESTS+=branch-relative-long
 TESTS+=noexec
 TESTS+=div
+TESTS+=clst
 
 Z13_TESTS=vistr
 $(Z13_TESTS): CFLAGS+=-march=z13 -O2

tests/tcg/s390x/clst.c

@@ -0,0 +1,82 @@
+#define _GNU_SOURCE
+#include <stdio.h>
+#include <stdlib.h>
+
+static int clst(char sep, const char **s1, const char **s2)
+{
+    const char *r1 = *s1;
+    const char *r2 = *s2;
+    int cc;
+
+    do {
+        register int r0 asm("r0") = sep;
+
+        asm("clst %[r1],%[r2]\n"
+            "ipm %[cc]\n"
+            "srl %[cc],28"
+            : [r1] "+r" (r1), [r2] "+r" (r2), "+r" (r0), [cc] "=r" (cc)
+            :
+            : "cc");
+        *s1 = r1;
+        *s2 = r2;
+    } while (cc == 3);
+
+    return cc;
+}
+
+static const struct test {
+    const char *name;
+    char sep;
+    const char *s1;
+    const char *s2;
+    int exp_cc;
+    int exp_off;
+} tests[] = {
+    {
+        .name = "cc0",
+        .sep = 0,
+        .s1 = "aa",
+        .s2 = "aa",
+        .exp_cc = 0,
+        .exp_off = 0,
+    },
+    {
+        .name = "cc1",
+        .sep = 1,
+        .s1 = "a\x01",
+        .s2 = "aa\x01",
+        .exp_cc = 1,
+        .exp_off = 1,
+    },
+    {
+        .name = "cc2",
+        .sep = 2,
+        .s1 = "abc\x02",
+        .s2 = "abb\x02",
+        .exp_cc = 2,
+        .exp_off = 2,
+    },
+};
+
+int main(void)
+{
+    const struct test *t;
+    const char *s1, *s2;
+    size_t i;
+    int cc;
+
+    for (i = 0; i < sizeof(tests) / sizeof(tests[0]); i++) {
+        t = &tests[i];
+        s1 = t->s1;
+        s2 = t->s2;
+        cc = clst(t->sep, &s1, &s2);
+        if (cc != t->exp_cc ||
+                s1 != t->s1 + t->exp_off ||
+                s2 != t->s2 + t->exp_off) {
+            fprintf(stderr, "%s\n", t->name);
+            return EXIT_FAILURE;
+        }
+    }
+
+    return EXIT_SUCCESS;
+}