Check some features of P3109 Spec

Author: awf

test/test_p3109_spec.py

@@ -0,0 +1,60 @@
+# Copyright (c) 2024 Graphcore Ltd. All rights reserved.
+from typing import Callable
+import ml_dtypes
+import numpy as np
+import pytest
+
+from gfloat import FloatClass, Domain, decode_float, decode_ndarray
+from gfloat.formats import *
+
+
+def spec_is_normal(fi: FormatInfo, x: int):
+    r"""
+  Copy from spec:
+
+  \Case{\isNormal*<f>(x \in \{0, \NInf, \Inf, \NaN\}) \gives \False}\\
+  \Case{\isNormal*<f>(x) \gives
+    \begin{cases}
+      (x \mod 2^{\k_f - 1}) \div 2^{\p_f - 1} > 0 & \If \s_f = \Signed   \\
+      x \div 2^{\p_f - 1} > 0                     & \If \s_f = \Unsigned
+    \end{cases}
+  }
+  """
+    if x in (fi.code_of_zero, fi.code_of_posinf, fi.code_of_neginf, fi.code_of_nan):
+        return False
+
+    k_f = fi.k
+    p_f = fi.precision
+    if fi.is_signed:
+        #      (x \mod 2^{\k_f - 1}) \div 2^{\p_f - 1} > 0
+        return (x % 2 ** (k_f - 1)) // 2 ** (p_f - 1) > 0
+    else:
+        #      x \div 2^{\p_f - 1} > 0
+        return x // 2 ** (p_f - 1) > 0
+
+
+_p3109_formats_to_test = (
+    (2, 1),
+    (2, 2),
+    (3, 1),
+    (3, 2),
+    (3, 3),
+    (4, 1),
+    (4, 2),
+    (4, 3),
+    (4, 4),
+    (6, 1),
+    (6, 5),
+    (8, 3),
+    (8, 1),
+    (11, 3),
+)
+
+
+@pytest.mark.parametrize("k,p", _p3109_formats_to_test)
+def test_p3109_specials_signed(k: int, p: int) -> None:
+    fi = format_info_p3109(k, p, Domain.Extended)
+
+    for i in range(2**fi.k):
+        fv = decode_float(fi, i)
+        assert spec_is_normal(fi, i) == (fv.fclass == FloatClass.NORMAL)