[Fix] Same Subnormal value over all platform

quaddtype/numpy_quaddtype/src/quaddtype_main.c

@@ -30,6 +30,29 @@ py_is_longdouble_128(PyObject *self, PyObject *args)
     }
 }
 
+#ifdef SLEEF_QUAD_C
+static const Sleef_quad SMALLEST_SUBNORMAL_VALUE = SLEEF_QUAD_DENORM_MIN;
+#else
+// Use the exact same struct layout as the original buggy code
+static const union {
+    struct {
+#if defined(__BYTE_ORDER__) && (__BYTE_ORDER__ == __ORDER_BIG_ENDIAN__)
+        uint64_t h, l;
+#else
+        uint64_t l, h;
+#endif
+    } parts;
+    Sleef_quad value;
+} smallest_subnormal_const = {.parts = {
+#if defined(__BYTE_ORDER__) && (__BYTE_ORDER__ == __ORDER_BIG_ENDIAN__)
+                                      .h = 0x0000000000000000ULL, .l = 0x0000000000000001ULL
+#else
+                                      .l = 0x0000000000000001ULL, .h = 0x0000000000000000ULL
+#endif
+                              }};
+#define SMALLEST_SUBNORMAL_VALUE (smallest_subnormal_const.value)
+#endif
+
 static PyObject *
 get_sleef_constant(PyObject *self, PyObject *args)
 {
@@ -71,7 +94,12 @@ get_sleef_constant(PyObject *self, PyObject *args)
         result->value.sleef_value = SLEEF_QUAD_MIN;
     }
     else if (strcmp(constant_name, "smallest_subnormal") == 0) {
+#ifdef SLEEF_QUAD_C
+        // On platforms with native __float128 support, use the correct literal
         result->value.sleef_value = SLEEF_QUAD_DENORM_MIN;
+#else
+        result->value.sleef_value = SMALLEST_SUBNORMAL_VALUE;
+#endif
     }
     else if (strcmp(constant_name, "bits") == 0) {
         Py_DECREF(result);

quaddtype/numpy_quaddtype/src/scalar.c

@@ -15,10 +15,22 @@
 #include "scalar_ops.h"
 #include "dragon4.h"
 
+#ifdef Py_GIL_DISABLED
+static PyMutex scalar_mutex = {0};
+#endif
+
 QuadPrecisionObject *
 QuadPrecision_raw_new(QuadBackendType backend)
 {
-    QuadPrecisionObject *new = PyObject_New(QuadPrecisionObject, &QuadPrecision_Type);
+    QuadPrecisionObject *new;
+#ifdef Py_GIL_DISABLED
+    PyMutex_Lock(&scalar_mutex);
+#endif
+    new = PyObject_New(QuadPrecisionObject, &QuadPrecision_Type);
+#ifdef Py_GIL_DISABLED
+    PyMutex_Unlock(&scalar_mutex);
+#endif
+
     if (!new)
         return NULL;
     new->backend = backend;
@@ -184,19 +196,28 @@ QuadPrecision_str(QuadPrecisionObject *self)
 static PyObject *
 QuadPrecision_repr(QuadPrecisionObject *self)
 {
+#ifdef Py_GIL_DISABLED
+    PyMutex_Lock(&scalar_mutex);
+#endif
     PyObject *str = QuadPrecision_str(self);
     if (str == NULL) {
         return NULL;
     }
     const char *backend_str = (self->backend == BACKEND_SLEEF) ? "sleef" : "longdouble";
     PyObject *res = PyUnicode_FromFormat("QuadPrecision('%S', backend='%s')", str, backend_str);
     Py_DECREF(str);
+#ifdef Py_GIL_DISABLED
+    PyMutex_Unlock(&scalar_mutex);
+#endif
     return res;
 }
 
 static PyObject *
 QuadPrecision_repr_dragon4(QuadPrecisionObject *self)
 {
+#ifdef Py_GIL_DISABLED
+    PyMutex_Lock(&scalar_mutex);
+#endif
     Dragon4_Options opt = {.scientific = 1,
                            .digit_mode = DigitMode_Unique,
                            .cutoff_mode = CutoffMode_TotalLength,
@@ -226,6 +247,9 @@ QuadPrecision_repr_dragon4(QuadPrecisionObject *self)
     const char *backend_str = (self->backend == BACKEND_SLEEF) ? "sleef" : "longdouble";
     PyObject *res = PyUnicode_FromFormat("QuadPrecision('%S', backend='%s')", str, backend_str);
     Py_DECREF(str);
+#ifdef Py_GIL_DISABLED
+    PyMutex_Unlock(&scalar_mutex);
+#endif
     return res;
 }
 

quaddtype/tests/test_quaddtype.py

@@ -24,6 +24,16 @@ def test_finfo_constant(name):
     assert isinstance(getattr(numpy_quaddtype, name), QuadPrecision)
 
 
+def test_smallest_subnormal_value():
+    """Test that smallest_subnormal has the correct value across all platforms."""
+    smallest_sub = numpy_quaddtype.smallest_subnormal
+    repr_str = repr(smallest_sub)
+
+    # The repr should show QuadPrecision('6.0e-4966', backend='sleef')
+    assert "6.0e-4966" in repr_str, f"Expected '6.0e-4966' in repr, got {repr_str}"
+
+    assert smallest_sub > 0, "smallest_subnormal should be positive"
+
 @pytest.mark.parametrize("name,value", [("bits", 128), ("precision", 33)])
 def test_finfo_int_constant(name, value):
     assert getattr(numpy_quaddtype, name) == value