test_od: Add f128 test (actually a f80 test)

drinkcat · drinkcat · commit cd9e4010c689 · 2025-08-03T13:29:05.000+08:00
diff --git a/tests/by-util/test_od.rs b/tests/by-util/test_od.rs
@@ -333,6 +333,87 @@ fn test_f64() {
         .stdout_is(expected_output);
 }
 
+#[test]
+fn test_f128() {
+    // This actually tests f80 parsing (x86(-64) behavior.
+    // Top 48-bits are ignored, padded with semi-random values here
+    let input: [u8; 19 * 16] = [
+        // Examples from Wikipedia: https://en.wikipedia.org/wiki/Extended_precision
+        // ... m ....................................]  [exp+sign]  [ padding (48 bits) .....
+        0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xcf, // 3.64519953188247460252841 × 10^−4951 (smallest positive subnormal number)
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0x7f, 0x00, 0x00, 0xfe, 0xca, 0xfe, 0xca, 0xfe,
+        0xca, // 3.36210314311209350589816 × 10^−4932 (largest subnormal number)
+        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x80, 0x01, 0x00, 0xfe, 0xca, 0xfe, 0xca, 0xfe,
+        0xca, // 3.36210314311209350626268 × 10^−4932 (smallest positive normal number)
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xfe, 0x7f, 0xfe, 0xca, 0xfe, 0xca, 0xfe,
+        0xca, // 1.18973149535723176502126 × 10^4932 (largest normal number)
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xfe, 0x3f, 0xfe, 0xca, 0xfe, 0xca, 0xfe,
+        0xca, // 0.99999999999999999994579 (largest number less than one)
+        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x80, 0xff, 0x3f, 0xfe, 0xca, 0xfe, 0xca, 0xfe,
+        0xca, // 1 (one)
+        0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x80, 0xff, 0x3f, 0xfe, 0xca, 0xfe, 0xca, 0xfe,
+        0xca, // 1.00000000000000000010842 (smallest number larger than one)
+        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x80, 0x00, 0x40, 0xfe, 0xca, 0xfe, 0xca, 0xfe,
+        0xca, // 2
+        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x80, 0x00, 0xc0, 0xfe, 0xca, 0xfe, 0xca, 0xfe,
+        0xca, // -2
+        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xfe, 0xca, 0xfe, 0xca, 0xfe,
+        0xca, // 0
+        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x80, 0xfe, 0xca, 0xfe, 0xca, 0xfe,
+        0xca, // -0
+        0x35, 0xc2, 0x68, 0x21, 0xa2, 0xda, 0x0f, 0xc9, 0x00, 0x40, 0xfe, 0xca, 0xfe, 0xca, 0xfe,
+        0xca, //3.14159265358979323851281 (closest approximation to pi)
+        // Others:
+        0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, // 3.64519953188247460252841 × 10^−4951 (pseudo-subnormal number)
+        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xff, 0x7f, 0xfe, 0xca, 0xfe, 0xca, 0xfe,
+        0xca, // pseudo-infinity => parsed as nan
+        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x80, 0xff, 0x7f, 0xfe, 0xca, 0xfe, 0xca, 0xfe,
+        0xca, // infinity
+        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x80, 0xff, 0xff, 0xfe, 0xca, 0xfe, 0xca, 0xfe,
+        0xca, // -infinity
+        0xab, 0xcd, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xff, 0x7f, 0xfe, 0xca, 0xfe, 0xca, 0xfe,
+        0xca, // pseudo-nan
+        0xab, 0xba, 0x00, 0x00, 0x00, 0x00, 0x00, 0x80, 0xff, 0x7f, 0xfe, 0xca, 0xfe, 0xca, 0xfe,
+        0xca, // nan
+        0xab, 0xba, 0x00, 0x00, 0x00, 0x00, 0x00, 0x80, 0xff, 0xff, 0xfe, 0xca, 0xfe, 0xca, 0xfe,
+        0xca, // -nan
+    ];
+    let expected_output = unindent(
+        "
+            0000000   3.6451995318824746025e-4951
+            0000020   3.3621031431120935059e-4932
+            0000040   3.3621031431120935063e-4932
+            0000060    1.189731495357231765e+4932
+            0000100        0.99999999999999999995
+            0000120                             1
+            0000140         1.0000000000000000001
+            0000160                             2
+            0000200                            -2
+            0000220                             0
+            0000240                            -0
+            0000260         3.1415926535897932385
+            0000300   3.6451995318824746025e-4951
+            0000320                           nan
+            0000340                           inf
+            0000360                          -inf
+            0000400                           nan
+            0000420                           nan
+            0000440                          -nan
+            0000460
+            ",
+    );
+    new_ucmd!()
+        .arg("--endian=little")
+        .arg("-tfL")
+        .arg("-w16")
+        .run_piped_stdin(&input[..])
+        .success()
+        .no_stderr()
+        .stdout_is(expected_output);
+}
+
 #[test]
 fn test_multibyte() {
     let input = "’‐ˆ‘˜語🙂✅🐶𝛑Universität Tübingen \u{1B000}"; // spell-checker:disable-line
