1 files changed, 32 insertions, 0 deletions
diff --git a/lib/std/special/compiler_rt/floatunditf_test.zig b/lib/std/special/compiler_rt/floatunditf_test.zig
new file mode 100644
index 0000000000..5b4e195870
--- /dev/null
+++ b/lib/std/special/compiler_rt/floatunditf_test.zig
@@ -0,0 +1,32 @@
+const __floatunditf = @import("floatunditf.zig").__floatunditf;
+
+fn test__floatunditf(a: u128, expected_hi: u64, expected_lo: u64) void {
+    const x = __floatunditf(a);
+
+    const x_repr = @bitCast(u128, x);
+    const x_hi = @intCast(u64, x_repr >> 64);
+    const x_lo = @truncate(u64, x_repr);
+
+    if (x_hi == expected_hi and x_lo == expected_lo) {
+        return;
+    }
+    // nan repr
+    else if (expected_hi == 0x7fff800000000000 and expected_lo == 0x0) {
+        if ((x_hi & 0x7fff000000000000) == 0x7fff000000000000 and ((x_hi & 0xffffffffffff) > 0 or x_lo > 0)) {
+            return;
+        }
+    }
+
+    @panic("__floatunditf test failure");
+}
+
+test "floatunditf" {
+    test__floatunditf(0xffffffffffffffff, 0x403effffffffffff, 0xfffe000000000000);
+    test__floatunditf(0xfffffffffffffffe, 0x403effffffffffff, 0xfffc000000000000);
+    test__floatunditf(0x8000000000000000, 0x403e000000000000, 0x0);
+    test__floatunditf(0x7fffffffffffffff, 0x403dffffffffffff, 0xfffc000000000000);
+    test__floatunditf(0x123456789abcdef1, 0x403b23456789abcd, 0xef10000000000000);
+    test__floatunditf(0x2, 0x4000000000000000, 0x0);
+    test__floatunditf(0x1, 0x3fff000000000000, 0x0);
+    test__floatunditf(0x0, 0x0, 0x0);
+}