1 files changed, 87 insertions, 0 deletions
diff --git a/lib/libc/tests/string/ffs_test.c b/lib/libc/tests/string/ffs_test.c
new file mode 100644
index 000000000000..4b59385d712e
--- /dev/null
+++ b/lib/libc/tests/string/ffs_test.c
@@ -0,0 +1,87 @@
+/*-
+ * Copyright (c) 2023 The FreeBSD Foundation
+ *
+ * This software was developed by Robert Clausecker <fuz@FreeBSD.org>
+ * under sponsorship from the FreeBSD Foundation.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ''AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE
+ */
+
+#include <atf-c.h>
+#include <limits.h>
+#include <stdint.h>
+#include <strings.h>
+
+#ifndef FFS
+# define FFS ffs
+# define TYPE int
+# define TYPE_MIN INT_MIN
+#endif
+
+ATF_TC_WITHOUT_HEAD(zero);
+ATF_TC_BODY(zero, tc)
+{
+	ATF_CHECK_EQ((TYPE)0, FFS(0));
+}
+
+ATF_TC_WITHOUT_HEAD(twobit);
+ATF_TC_BODY(twobit, tc)
+{
+	const TYPE one = 1;
+	TYPE x;
+	const int n = sizeof(TYPE) * CHAR_BIT;
+	int i, j;
+
+	for (i = 0; i < n - 1; i++)
+		for (j = 0; j <= i; j++) {
+			x = one << i | one << j;
+			ATF_CHECK_EQ_MSG(j + 1, FFS(x),
+			    "%s(%#jx) == %d != %d", __STRING(FFS), (intmax_t)x, FFS(x), j + 1);
+		}
+}
+
+ATF_TC_WITHOUT_HEAD(twobitneg);
+ATF_TC_BODY(twobitneg, tc)
+{
+	const TYPE one = 1;
+	TYPE x;
+	const int n = sizeof(TYPE) * CHAR_BIT;
+	int i, j;
+
+	for (i = 0; i < n - 1; i++)
+		for (j = 0; j <= i; j++) {
+			x = one << i | one << j | TYPE_MIN;
+			ATF_CHECK_EQ_MSG(j + 1, FFS(x),
+			    "%s(%#jx) == %d != %d", __STRING(FFS), (intmax_t)x, FFS(x), j + 1);
+		}
+}
+
+
+ATF_TP_ADD_TCS(tp)
+{
+
+	ATF_TP_ADD_TC(tp, zero);
+	ATF_TP_ADD_TC(tp, twobit);
+	ATF_TP_ADD_TC(tp, twobitneg);
+
+	return (atf_no_error());
+}