diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 9e4f157..a1b014f 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -1,8 +1,7 @@
 cmake_minimum_required(VERSION 3.0)
 
-################################
+################################################
 
-include_directories(core)
 include_directories(utils)
 include_directories(all_cases)
 
@@ -10,12 +9,12 @@ include_directories(raw_code)
 include_directories(short_code)
 include_directories(common_code)
 
-include_directories(fast_cal)
+include_directories(core)
 include_directories(analyse)
+include_directories(fast_cal)
 
-################################
+################################################
 
-add_subdirectory(core)
 add_subdirectory(utils)
 add_subdirectory(all_cases)
 
@@ -23,17 +22,16 @@ add_subdirectory(raw_code)
 add_subdirectory(short_code)
 add_subdirectory(common_code)
 
-add_subdirectory(fast_cal)
+add_subdirectory(core)
 add_subdirectory(analyse)
+add_subdirectory(fast_cal)
 
-################################
+################################################
 
 add_executable(klotski main.cc)
-#add_executable(klotski main.cc basic_ranges_demo.cc)
 
-################################
+################################################
 
-target_link_libraries(klotski core)
 target_link_libraries(klotski utils)
 target_link_libraries(klotski all_cases)
 
@@ -41,9 +39,10 @@ target_link_libraries(klotski raw_code)
 target_link_libraries(klotski short_code)
 target_link_libraries(klotski common_code)
 
-target_link_libraries(klotski fast_cal)
+target_link_libraries(klotski core)
 target_link_libraries(klotski analyse)
+target_link_libraries(klotski fast_cal)
 
 target_link_libraries(klotski pthread)
 
-################################
+################################################
diff --git a/src/common_code/CMakeLists.txt b/src/common_code/CMakeLists.txt
index 0d4ebd2..f4e40fd 100644
--- a/src/common_code/CMakeLists.txt
+++ b/src/common_code/CMakeLists.txt
@@ -1,4 +1,4 @@
 cmake_minimum_required(VERSION 3.0)
 
 add_library(common_code convert.cc serialize.cc common_code.cc)
-target_link_libraries(common_code utils raw_code)
+target_link_libraries(common_code utils)
diff --git a/src/utils/CMakeLists.txt b/src/utils/CMakeLists.txt
index c3481e7..8686549 100644
--- a/src/utils/CMakeLists.txt
+++ b/src/utils/CMakeLists.txt
@@ -1,4 +1,3 @@
 cmake_minimum_required(VERSION 3.0)
 
 add_library(utils common.cc)
-target_link_libraries(utils short_code)
diff --git a/src/utils/common.cc b/src/utils/common.cc
index 1886b76..25f780f 100644
--- a/src/utils/common.cc
+++ b/src/utils/common.cc
@@ -21,7 +21,8 @@ uint8_t Common::check_range(uint32_t head, uint32_t range) { // check generated
     int block_offset = 1;
     uint32_t cache = M_2x2 << head; // fill 2x2 block
     for (int addr = 0; range; range >>= 2, ++block_offset) { // traverse every 2-bits
-        while (cache >> addr & 0b1) {
+        // TODO: will addr >= 32 in some special cases?
+        while ((cache >> addr) & 0b1) {
             ++addr; // search next unfilled block
         }
         switch (range & 0b11) {
diff --git a/src/utils/common.h b/src/utils/common.h
index da713c2..ec038bc 100644
--- a/src/utils/common.h
+++ b/src/utils/common.h
@@ -2,6 +2,7 @@
 
 #include <cstdint>
 
+/// 0b101 and 0b110 reserved
 #define B_space 0b000
 #define B_fill  0b111
 #define B_1x2   0b001
@@ -9,13 +10,18 @@
 #define B_1x1   0b011
 #define B_2x2   0b100
 
+///  C_1x1            |  C_1x2            |  C_2x1            |  C_2x2
+///  011 000 000 000  |  001 111 000 000  |  010 000 000 000  |  100 111 000 000
+///  000 000 000 000  |  000 000 000 000  |  111 000 000 000  |  111 111 000 000
+///  ...              |  ...              |  ...              |  ...
+
 #define C_1x1 (uint64_t)0x3 // 011
 #define C_1x2 (uint64_t)0x39 // 111 001
 #define C_2x1 (uint64_t)0x7002 // 111 000 000 000 010
 #define C_2x2 (uint64_t)0x3F03C // 111 111 000 000 111 100
 
-///  C_1x1            |  C_1x2            |  C_2x1            |  C_2x2
-///  011 000 000 000  |  001 111 000 000  |  010 000 000 000  |  100 111 000 000
+///  F_1x1            |  F_1x2            |  F_2x1            |  F_2x2
+///  111 000 000 000  |  111 111 000 000  |  111 000 000 000  |  111 111 000 000
 ///  000 000 000 000  |  000 000 000 000  |  111 000 000 000  |  111 111 000 000
 ///  ...              |  ...              |  ...              |  ...
 
@@ -24,9 +30,9 @@
 #define F_2x1 (uint64_t)0x7007 // 111 000 000 000 111
 #define F_2x2 (uint64_t)0x3F03F // 111 111 000 000 111 111
 
-///  F_1x1            |  F_1x2            |  F_2x1            |  F_2x2
-///  111 000 000 000  |  111 111 000 000  |  111 000 000 000  |  111 111 000 000
-///  000 000 000 000  |  000 000 000 000  |  111 000 000 000  |  111 111 000 000
+///  F_1x1_R          |  F_1x1_D          |  F_2x1_R          |  F_1x2_D
+///  000 111 000 000  |  000 000 000 000  |  000 111 000 000  |  000 000 000 000
+///  000 000 000 000  |  111 000 000 000  |  000 111 000 000  |  111 111 000 000
 ///  ...              |  ...              |  ...              |  ...
 
 #define F_1x1_R (uint64_t)0x38 // 111 000
@@ -34,16 +40,8 @@
 #define F_2x1_R (uint64_t)0x38038 // 111 000 000 000 111 000
 #define F_1x2_D (uint64_t)0x3F000 // 111 111 000 000 000 000
 
-///  F_1x1_R          |  F_1x1_D          |  F_2x1_R          |  F_1x2_D
-///  000 111 000 000  |  000 000 000 000  |  000 111 000 000  |  000 000 000 000
-///  000 000 000 000  |  111 000 000 000  |  000 111 000 000  |  111 111 000 000
-///  ...              |  ...              |  ...              |  ...
-
 class Common {
 public:
     static uint32_t range_reverse(uint32_t bin);
-//    static bool check_case(uint32_t head, uint32_t range);
-
-    // TODO: with broken block offset return
     static uint8_t check_range(uint32_t head, uint32_t range);
 };