diff --git a/include/pocketpy/cffi.h b/include/pocketpy/cffi.h
index dd5c098e..802b8bb9 100644
--- a/include/pocketpy/cffi.h
+++ b/include/pocketpy/cffi.h
@@ -37,7 +37,6 @@ struct VoidP{
 
     void* ptr;
     VoidP(void* ptr): ptr(ptr){}
-    VoidP(): ptr(nullptr){}
 
     bool operator==(const VoidP& other) const {
         return ptr == other.ptr;
diff --git a/include/pocketpy/linalg.h b/include/pocketpy/linalg.h
index 57710b98..c3bdc77b 100644
--- a/include/pocketpy/linalg.h
+++ b/include/pocketpy/linalg.h
@@ -234,7 +234,7 @@ struct Mat3x3{
 
     bool is_affine() const{
         float det = _11 * _22 - _12 * _21;
-        if(!isclose(det, 0)) return false;
+        if(isclose(det, 0)) return false;
         return _31 == 0.0f && _32 == 0.0f && _33 == 1.0f;
     }
 
diff --git a/include/typings/c.pyi b/include/typings/c.pyi
index d3365adc..3a0348fe 100644
--- a/include/typings/c.pyi
+++ b/include/typings/c.pyi
@@ -7,14 +7,13 @@ def memset(ptr: 'void_p', value: int, size: int) -> None: ...
 def memcpy(dst: 'void_p', src: 'void_p', size: int) -> None: ...
 
 class void_p:
+    def __init__(self, addr: int): ...
     def __add__(self, i: int) -> 'void_p': ...
     def __sub__(self, i: int) -> 'void_p': ...
     def __eq__(self, other: 'void_p') -> bool: ...
     def __ne__(self, other: 'void_p') -> bool: ...
 
     def hex(self) -> str: ...
-    @staticmethod
-    def from_hex(s: str) -> 'void_p': ...
 
     def read_char(self) -> int: ...
     def read_uchar(self) -> int: ...
diff --git a/src/cffi.cpp b/src/cffi.cpp
index 5369a44f..27e98605 100644
--- a/src/cffi.cpp
+++ b/src/cffi.cpp
@@ -3,15 +3,12 @@
 namespace pkpy{
 
     void VoidP::_register(VM* vm, PyObject* mod, PyObject* type){
-        vm->bind_default_constructor<VoidP>(type);
-
-        vm->bind_func<1>(type, "from_hex", [](VM* vm, ArgsView args){
-            std::string s = CAST(Str&, args[0]).str();
-            size_t size;
-            intptr_t ptr = std::stoll(s, &size, 16);
-            if(size != s.size()) vm->ValueError("invalid literal for void_p(): " + s);
-            return VAR_T(VoidP, (void*)ptr);
+        vm->bind_constructor<2>(type, [](VM* vm, ArgsView args){
+            Type cls = PK_OBJ_GET(Type, args[0]);
+            i64 addr = CAST(i64, args[1]);
+            return vm->heap.gcnew<VoidP>(cls, reinterpret_cast<void*>(addr));
         });
+
         vm->bind_method<0>(type, "hex", [](VM* vm, ArgsView args){
             VoidP& self = _CAST(VoidP&, args[0]);
             return VAR(self.hex());
diff --git a/tests/40_class.py b/tests/40_class.py
index 320c0bb4..3c167f37 100644
--- a/tests/40_class.py
+++ b/tests/40_class.py
@@ -109,11 +109,3 @@ class B(A):
 # assert B.a == 1  ...bug here
 assert B.b == 3
 assert B.c == 4
-
-import c
-
-class A(c.void_p):
-    pass
-    
-a = A()
-assert repr(a).startswith('<void* at')
diff --git a/tests/40_class_ex.py b/tests/40_class_ex.py
index 7856aeab..de9e5607 100644
--- a/tests/40_class_ex.py
+++ b/tests/40_class_ex.py
@@ -115,5 +115,5 @@ import c
 class A(c.void_p):
     pass
     
-a = A()
+a = A(0)
 assert repr(a).startswith('<void* at')
diff --git a/tests/99_cffi_2.py b/tests/99_cffi_2.py
index 09834cd4..3f87c079 100644
--- a/tests/99_cffi_2.py
+++ b/tests/99_cffi_2.py
@@ -1,38 +1,6 @@
 import c
 
-assert c.void_p.from_hex('0x2568b60').hex() == '0x2568b60'
-
-# ------------------------------------------------
-class HexAddress:
-    def __init__(self, address):
-        if not address.startswith("0x"):  # 确保地址以0x开头
-            raise ValueError("Address should start with '0x'.")
-        self.address = address[2:]  # 去除0x前缀，并保存十六进制字符串
-
-    def __str__(self):
-        return "0x" + self.address  
-
-    def __add__(self, other):
-        if isinstance(other, int):
-            return HexAddress(hex(int(self.address, 16) + other))  # 将字符串地址转为整数进行运算
-        elif isinstance(other, HexAddress):
-            return HexAddress(hex(int(self.address, 16) + int(other.address, 16)))  # 将字符串地址转为整数进行运算
-        else:
-            raise TypeError("Unsupported operand type for +: HexAddress and {}".format(type(other)))
-
-    def __sub__(self, other):
-        if isinstance(other, int):
-            return HexAddress(hex(int(self.address, 16) - other))  # 将字符串地址转为整数进行运算
-        elif isinstance(other, HexAddress):
-            return HexAddress(hex(int(self.address, 16) - int(other.address, 16)))  # 将字符串地址转为整数进行运算
-        else:
-            raise TypeError("Unsupported operand type for -: HexAddress and {}".format(type(other)))
-
-c_void_1 = c.malloc(8)
-
-assert (c_void_1 + 8).hex() == c.void_p.from_hex(str(HexAddress(c_void_1.hex()) + 8)).hex()
-assert (c_void_1 - 8).hex() == c.void_p.from_hex(str(HexAddress(c_void_1.hex()) - 8)).hex()
-
+assert c.NULL == c.void_p(0)
 # ------------------------------------------------
 # 此处测试并不完全
 c_void_1 = c.malloc(8)