diff --git a/includes/type/leb128.pat b/includes/type/leb128.pat
index 4a50f17..7231c19 100644
--- a/includes/type/leb128.pat
+++ b/includes/type/leb128.pat
@@ -5,29 +5,51 @@
 
 namespace type {
 	
-	struct LEB128 {
+	struct _LEB128 {
 		u8 array[while($ == addressof(this) || std::mem::read_unsigned($-1, 1) & 0x80 != 0)] [[hidden]];
-	} [[sealed, format("type::impl::format_leb128"), transform("type::impl::transform_leb128")]];
+	} [[sealed]];
+
+	using uLEB128 = _LEB128 [[format("type::impl::format_uleb128"), transform("type::impl::transform_uleb128")]];
+	using sLEB128 = _LEB128 [[format("type::impl::format_sleb128"), transform("type::impl::transform_sleb128")]];
+
+	using LEB128 = uLEB128;
 	
 	namespace impl {
 	
-		fn transform_leb128_array(auto array) {
+		fn transform_uleb128_array(auto array) {
 			u128 res = array[0] & 0x7f;
 			for(u8 i = 1, array[i-1] & 0x80 != 0, i+=1) {
-				res |= u64(array[i] & 0x7f) << 7 * i;
+				res |= u128(array[i] & 0x7f) << 7 * i;
+			}
+			return res;
+		};
+
+		fn transform_sleb128_array(auto array) {			
+			s128 res = type::impl::transform_uleb128_array(array);
+			if (res & 0x40 != 0) {
+				res |= ~0 << (sizeof(array) / sizeof(u8)) * 7;
 			}
 			return res;
 		};
 		
-		fn format_leb128(auto leb128) {
-			u128 res = type::impl::transform_leb128_array(leb128.array);
+		fn format_uleb128(auto leb128) {
+			u128 res = type::impl::transform_uleb128_array(leb128.array);
 			return std::format("{} ({:#x})", res, res);
 		};
 	
-		fn transform_leb128(auto leb128) {
-			return type::impl::transform_leb128_array(leb128.array);
+		fn transform_uleb128(auto leb128) {
+			return type::impl::transform_uleb128_array(leb128.array);
 		};
+
+		fn format_sleb128(auto leb128) {
+			s128 res = type::impl::transform_sleb128_array(leb128.array);
+			return std::format("{} ({:#x})", res, res);
+		};
+	
+		fn transform_sleb128(auto leb128) {
+			return type::impl::transform_sleb128_array(leb128.array);
+		};
+
 	}
 	
 }
-