gh-132908: Add math.isnormal/issubnormal() functions (GH132935)

Modules/mathmodule.c

@@ -3118,6 +3118,44 @@ math_isfinite_impl(PyObject *module, double x)
 }
 
 
+/*[clinic input]
+math.isnormal
+
+    x: double
+    /
+
+Return True if x is normal, and False otherwise.
+[clinic start generated code]*/
+
+static PyObject *
+math_isnormal_impl(PyObject *module, double x)
+/*[clinic end generated code: output=c7b302b5b89c3541 input=fdaa00c58aa7bc17]*/
+{
+    return PyBool_FromLong(isnormal(x));
+}
+
+
+/*[clinic input]
+math.issubnormal
+
+    x: double
+    /
+
+Return True if x is subnormal, and False otherwise.
+[clinic start generated code]*/
+
+static PyObject *
+math_issubnormal_impl(PyObject *module, double x)
+/*[clinic end generated code: output=4e76ac98ddcae761 input=9a20aba7107d0d95]*/
+{
+#if defined(__STDC_VERSION__) && __STDC_VERSION__ >= 202311L
+    return PyBool_FromLong(issubnormal(x));
+#else
+    return PyBool_FromLong(isfinite(x) && x && !isnormal(x));
+#endif
+}
+
+
 /*[clinic input]
 math.isnan
 
@@ -4145,6 +4183,8 @@ static PyMethodDef math_methods[] = {
     MATH_HYPOT_METHODDEF
     MATH_ISCLOSE_METHODDEF
     MATH_ISFINITE_METHODDEF
+    MATH_ISNORMAL_METHODDEF
+    MATH_ISSUBNORMAL_METHODDEF
     MATH_ISINF_METHODDEF
     MATH_ISNAN_METHODDEF
     MATH_ISQRT_METHODDEF