1 files changed, 37 insertions, 0 deletions
diff --git a/lib/std/special/compiler_rt/modti3_test.zig b/lib/std/special/compiler_rt/modti3_test.zig
new file mode 100644
index 0000000000..10f81d59d2
--- /dev/null
+++ b/lib/std/special/compiler_rt/modti3_test.zig
@@ -0,0 +1,37 @@
+const __modti3 = @import("modti3.zig").__modti3;
+const testing = @import("std").testing;
+
+fn test__modti3(a: i128, b: i128, expected: i128) void {
+    const x = __modti3(a, b);
+    testing.expect(x == expected);
+}
+
+test "modti3" {
+    test__modti3(0, 1, 0);
+    test__modti3(0, -1, 0);
+    test__modti3(5, 3, 2);
+    test__modti3(5, -3, 2);
+    test__modti3(-5, 3, -2);
+    test__modti3(-5, -3, -2);
+
+    test__modti3(0x8000000000000000, 1, 0x0);
+    test__modti3(0x8000000000000000, -1, 0x0);
+    test__modti3(0x8000000000000000, 2, 0x0);
+    test__modti3(0x8000000000000000, -2, 0x0);
+    test__modti3(0x8000000000000000, 3, 2);
+    test__modti3(0x8000000000000000, -3, 2);
+
+    test__modti3(make_ti(0x8000000000000000, 0), 1, 0x0);
+    test__modti3(make_ti(0x8000000000000000, 0), -1, 0x0);
+    test__modti3(make_ti(0x8000000000000000, 0), 2, 0x0);
+    test__modti3(make_ti(0x8000000000000000, 0), -2, 0x0);
+    test__modti3(make_ti(0x8000000000000000, 0), 3, -2);
+    test__modti3(make_ti(0x8000000000000000, 0), -3, -2);
+}
+
+fn make_ti(high: u64, low: u64) i128 {
+    var result: u128 = high;
+    result <<= 64;
+    result |= low;
+    return @bitCast(i128, result);
+}