diff --git a/crates/rb-sys-build/src/bindings.rs b/crates/rb-sys-build/src/bindings.rs
index 59e785f4..cd48e6e3 100644
--- a/crates/rb-sys-build/src/bindings.rs
+++ b/crates/rb-sys-build/src/bindings.rs
@@ -68,9 +68,7 @@ pub fn generate(
     let bindings = if cfg!(feature = "bindgen-deprecated-types") {
         bindings
     } else {
-        bindings
-            .blocklist_item("^ruby_fl_type.*")
-            .blocklist_item("^_bindgen_ty_9.*")
+        bindings.blocklist_item("^_bindgen_ty_9.*")
     };
 
     let bindings = opaqueify_bindings(rbconfig, bindings, &mut wrapper_h);
diff --git a/crates/rb-sys-tests/src/stable_api_test.rs b/crates/rb-sys-tests/src/stable_api_test.rs
index 93cb078d..f639f88e 100644
--- a/crates/rb-sys-tests/src/stable_api_test.rs
+++ b/crates/rb-sys-tests/src/stable_api_test.rs
@@ -213,6 +213,60 @@ parity_test!(
     }
 );
 
+parity_test!(
+    name: test_bignum_positive_p_evaled,
+    func: bignum_positive_p,
+    data_factory: {
+      ruby_eval!("2 ** 64")
+    },
+    expected: true
+);
+
+parity_test!(
+    name: test_bignum_negative_p_evaled,
+    func: bignum_negative_p,
+    data_factory: {
+      ruby_eval!("-(2 ** 64)")
+    },
+    expected: true
+);
+
+parity_test!(
+    name: test_bignum_positive_p_for_zero,
+    func: bignum_positive_p,
+    data_factory: {
+      unsafe { rb_sys::rb_int2big(0) }
+    },
+    expected: true
+);
+
+parity_test!(
+    name: test_bignum_negative_p_for_zero,
+    func: bignum_negative_p,
+    data_factory: {
+      unsafe { rb_sys::rb_int2big(0) }
+    },
+    expected: false
+);
+
+parity_test!(
+    name: test_bignum_positive_p,
+    func: bignum_positive_p,
+    data_factory: {
+      unsafe { rb_sys::rb_int2big(64) }
+    },
+    expected: true
+);
+
+parity_test!(
+    name: test_bignum_negative_p,
+    func: bignum_negative_p,
+    data_factory: {
+      unsafe { rb_sys::rb_int2big(-1) }
+    },
+    expected: true
+);
+
 parity_test!(
     name: test_builtin_type_for_string,
     func: builtin_type,
diff --git a/crates/rb-sys/src/stable_api.rs b/crates/rb-sys/src/stable_api.rs
index d97204da..fe3b0cb8 100644
--- a/crates/rb-sys/src/stable_api.rs
+++ b/crates/rb-sys/src/stable_api.rs
@@ -54,6 +54,24 @@ pub trait StableApiDefinition {
     /// is valid.
     unsafe fn rarray_const_ptr(&self, obj: VALUE) -> *const VALUE;
 
+    /// Tests if a bignum is positive.
+    ///
+    /// # Safety
+    /// This function is unsafe because it dereferences a raw pointer to get
+    /// access to underlying RBasic struct. The caller must ensure that the
+    /// `VALUE` is a valid pointer to a bignum.
+    unsafe fn bignum_positive_p(&self, obj: VALUE) -> bool;
+
+    /// Tests if a bignum is negative.
+    ///
+    /// # Safety
+    /// This function is unsafe because it dereferences a raw pointer to get
+    /// access to underlying RBasic struct. The caller must ensure that the
+    /// `VALUE` is a valid pointer to a bignum.
+    unsafe fn bignum_negative_p(&self, obj: VALUE) -> bool {
+        !self.bignum_positive_p(obj)
+    }
+
     /// Tests if the given value is a special constant.
     fn special_const_p(&self, value: VALUE) -> bool;
 
diff --git a/crates/rb-sys/src/stable_api/compiled.c b/crates/rb-sys/src/stable_api/compiled.c
index a877f7cd..739f6634 100644
--- a/crates/rb-sys/src/stable_api/compiled.c
+++ b/crates/rb-sys/src/stable_api/compiled.c
@@ -25,6 +25,17 @@ impl_special_const_p(VALUE obj) {
   return SPECIAL_CONST_P(obj);
 }
 
+int
+impl_bignum_positive_p(VALUE obj) {
+  return RBIGNUM_POSITIVE_P(obj);
+}
+
+int
+impl_bignum_negative_p(VALUE obj) {
+  return RBIGNUM_NEGATIVE_P(obj);
+}
+
+
 enum ruby_value_type
 impl_builtin_type(VALUE obj) {
   return RB_BUILTIN_TYPE(obj);
diff --git a/crates/rb-sys/src/stable_api/compiled.rs b/crates/rb-sys/src/stable_api/compiled.rs
index 418cb836..c142e7c2 100644
--- a/crates/rb-sys/src/stable_api/compiled.rs
+++ b/crates/rb-sys/src/stable_api/compiled.rs
@@ -19,6 +19,12 @@ extern "C" {
     #[link_name = "impl_special_const_p"]
     fn impl_special_const_p(value: VALUE) -> bool;
 
+    #[link_name = "impl_bignum_positive_p"]
+    fn impl_bignum_positive_p(obj: VALUE) -> bool;
+
+    #[link_name = "impl_bignum_negative_p"]
+    fn impl_bignum_negative_p(obj: VALUE) -> bool;
+
     #[link_name = "impl_builtin_type"]
     fn impl_builtin_type(obj: VALUE) -> ruby_value_type;
 
@@ -93,6 +99,16 @@ impl StableApiDefinition for Definition {
         unsafe { impl_special_const_p(value) }
     }
 
+    #[inline]
+    unsafe fn bignum_positive_p(&self, obj: VALUE) -> bool {
+        impl_bignum_positive_p(obj)
+    }
+
+    #[inline]
+    unsafe fn bignum_negative_p(&self, obj: VALUE) -> bool {
+        impl_bignum_negative_p(obj)
+    }
+
     #[inline]
     unsafe fn builtin_type(&self, obj: VALUE) -> ruby_value_type {
         impl_builtin_type(obj)
diff --git a/crates/rb-sys/src/stable_api/ruby_2_6.rs b/crates/rb-sys/src/stable_api/ruby_2_6.rs
index 408f096a..a36e85be 100644
--- a/crates/rb-sys/src/stable_api/ruby_2_6.rs
+++ b/crates/rb-sys/src/stable_api/ruby_2_6.rs
@@ -88,6 +88,13 @@ impl StableApiDefinition for Definition {
         ptr
     }
 
+    #[inline]
+    unsafe fn bignum_positive_p(&self, obj: VALUE) -> bool {
+        let rbasic = obj as *const crate::RBasic;
+
+        ((*rbasic).flags & crate::ruby_fl_type::RUBY_FL_USER1 as VALUE) != 0
+    }
+
     #[inline]
     fn special_const_p(&self, value: VALUE) -> bool {
         let is_immediate = value & (crate::special_consts::IMMEDIATE_MASK as VALUE) != 0;
diff --git a/crates/rb-sys/src/stable_api/ruby_2_7.rs b/crates/rb-sys/src/stable_api/ruby_2_7.rs
index b9ef5225..f228c7c3 100644
--- a/crates/rb-sys/src/stable_api/ruby_2_7.rs
+++ b/crates/rb-sys/src/stable_api/ruby_2_7.rs
@@ -88,6 +88,13 @@ impl StableApiDefinition for Definition {
         ptr
     }
 
+    #[inline]
+    unsafe fn bignum_positive_p(&self, obj: VALUE) -> bool {
+        let rbasic = obj as *const crate::RBasic;
+
+        ((*rbasic).flags & crate::ruby_fl_type::RUBY_FL_USER1 as VALUE) != 0
+    }
+
     #[inline]
     fn special_const_p(&self, value: VALUE) -> bool {
         let is_immediate = value & (crate::special_consts::IMMEDIATE_MASK as VALUE) != 0;
diff --git a/crates/rb-sys/src/stable_api/ruby_3_0.rs b/crates/rb-sys/src/stable_api/ruby_3_0.rs
index c2eb0bf0..cc059f91 100644
--- a/crates/rb-sys/src/stable_api/ruby_3_0.rs
+++ b/crates/rb-sys/src/stable_api/ruby_3_0.rs
@@ -96,6 +96,13 @@ impl StableApiDefinition for Definition {
         }
     }
 
+    #[inline]
+    unsafe fn bignum_positive_p(&self, obj: VALUE) -> bool {
+        let rbasic = obj as *const crate::RBasic;
+
+        ((*rbasic).flags & crate::ruby_fl_type::RUBY_FL_USER1 as VALUE) != 0
+    }
+
     #[inline]
     fn special_const_p(&self, value: VALUE) -> bool {
         let is_immediate = value & (crate::special_consts::IMMEDIATE_MASK as VALUE) != 0;
diff --git a/crates/rb-sys/src/stable_api/ruby_3_1.rs b/crates/rb-sys/src/stable_api/ruby_3_1.rs
index 646fa5a3..e6b747e0 100644
--- a/crates/rb-sys/src/stable_api/ruby_3_1.rs
+++ b/crates/rb-sys/src/stable_api/ruby_3_1.rs
@@ -89,6 +89,13 @@ impl StableApiDefinition for Definition {
         ret
     }
 
+    #[inline]
+    unsafe fn bignum_positive_p(&self, obj: VALUE) -> bool {
+        let rbasic = obj as *const crate::RBasic;
+
+        ((*rbasic).flags & crate::ruby_fl_type::RUBY_FL_USER1 as VALUE) != 0
+    }
+
     #[inline]
     fn special_const_p(&self, value: VALUE) -> bool {
         let is_immediate = value & (crate::special_consts::IMMEDIATE_MASK as VALUE) != 0;
diff --git a/crates/rb-sys/src/stable_api/ruby_3_2.rs b/crates/rb-sys/src/stable_api/ruby_3_2.rs
index 763158ae..c6f66e5f 100644
--- a/crates/rb-sys/src/stable_api/ruby_3_2.rs
+++ b/crates/rb-sys/src/stable_api/ruby_3_2.rs
@@ -83,6 +83,13 @@ impl StableApiDefinition for Definition {
         ptr
     }
 
+    #[inline]
+    unsafe fn bignum_positive_p(&self, obj: VALUE) -> bool {
+        let rbasic = obj as *const crate::RBasic;
+
+        ((*rbasic).flags & crate::ruby_fl_type::RUBY_FL_USER1 as VALUE) != 0
+    }
+
     #[inline]
     fn special_const_p(&self, value: VALUE) -> bool {
         let is_immediate = (value) & (crate::special_consts::IMMEDIATE_MASK as VALUE) != 0;
diff --git a/crates/rb-sys/src/stable_api/ruby_3_3.rs b/crates/rb-sys/src/stable_api/ruby_3_3.rs
index 11afd1cd..d4bd09fa 100644
--- a/crates/rb-sys/src/stable_api/ruby_3_3.rs
+++ b/crates/rb-sys/src/stable_api/ruby_3_3.rs
@@ -76,6 +76,13 @@ impl StableApiDefinition for Definition {
         ptr
     }
 
+    #[inline]
+    unsafe fn bignum_positive_p(&self, obj: VALUE) -> bool {
+        let rbasic = obj as *const crate::RBasic;
+
+        ((*rbasic).flags & crate::ruby_fl_type::RUBY_FL_USER1 as VALUE) != 0
+    }
+
     #[inline]
     fn special_const_p(&self, value: VALUE) -> bool {
         let is_immediate = (value) & (crate::special_consts::IMMEDIATE_MASK as VALUE) != 0;
diff --git a/crates/rb-sys/src/stable_api/ruby_3_4.rs b/crates/rb-sys/src/stable_api/ruby_3_4.rs
index 9cd51405..a4a9f7dc 100644
--- a/crates/rb-sys/src/stable_api/ruby_3_4.rs
+++ b/crates/rb-sys/src/stable_api/ruby_3_4.rs
@@ -84,6 +84,13 @@ impl StableApiDefinition for Definition {
         is_immediate || !test
     }
 
+    #[inline]
+    unsafe fn bignum_positive_p(&self, obj: VALUE) -> bool {
+        let rbasic = obj as *const crate::RBasic;
+
+        ((*rbasic).flags & crate::ruby_fl_type::RUBY_FL_USER1 as VALUE) != 0
+    }
+
     #[inline]
     unsafe fn builtin_type(&self, obj: VALUE) -> crate::ruby_value_type {
         let rbasic = obj as *const crate::RBasic;