Add basic f16 and f128 modules

Create empty modules so `rustdoc` has someplace to link to for these
types.

1 files changed, 46 insertions, 0 deletions

diff --git a/library/std/src/f16/tests.rs b/library/std/src/f16/tests.rs
new file mode 100644
index 00000000000..d65c43eca4b
--- /dev/null
+++ b/library/std/src/f16/tests.rs
@@ -0,0 +1,46 @@
+#![allow(dead_code)] // FIXME(f16_f128): remove once constants are used
+
+// We run out of precision pretty quickly with f16
+const F16_APPROX_L1: f16 = 0.001;
+const F16_APPROX_L2: f16 = 0.01;
+const F16_APPROX_L3: f16 = 0.1;
+const F16_APPROX_L4: f16 = 0.5;
+
+/// Smallest number
+const TINY_BITS: u16 = 0x1;
+/// Next smallest number
+const TINY_UP_BITS: u16 = 0x2;
+/// Exponent = 0b11...10, Sifnificand 0b1111..10. Min val > 0
+const MAX_DOWN_BITS: u16 = 0x7bfe;
+/// Zeroed exponent, full significant
+const LARGEST_SUBNORMAL_BITS: u16 = 0x03ff;
+/// Exponent = 0b1, zeroed significand
+const SMALLEST_NORMAL_BITS: u16 = 0x0400;
+/// First pattern over the mantissa
+const NAN_MASK1: u16 = 0x02aa;
+/// Second pattern over the mantissa
+const NAN_MASK2: u16 = 0x0155;
+
+/// Compare by value
+#[allow(unused_macros)]
+macro_rules! assert_f16_eq {
+    ($a:expr, $b:expr) => {
+        let (l, r): (&f16, &f16) = (&$a, &$b);
+        assert_eq!(*l, *r, "\na: {:#018x}\nb: {:#018x}", l.to_bits(), r.to_bits())
+    };
+}
+
+/// Compare by representation
+#[allow(unused_macros)]
+macro_rules! assert_f16_biteq {
+    ($a:expr, $b:expr) => {
+        let (l, r): (&f16, &f16) = (&$a, &$b);
+        let lb = l.to_bits();
+        let rb = r.to_bits();
+        assert_eq!(
+            lb, rb,
+            "float {:?} is not bitequal to {:?}.\na: {:#018x}\nb: {:#018x}",
+            *l, *r, lb, rb
+        );
+    };
+}