diff --git a/src/all_cases/all_cases.cc b/src/all_cases/all_cases.cc
index 0ee0b07..aa912af 100644
--- a/src/all_cases/all_cases.cc
+++ b/src/all_cases/all_cases.cc
@@ -35,17 +35,194 @@ void AllCases::build() { // ensure that all cases available
     }
 }
 
+
+//int32_t AllCases::check_case(uint32_t head, uint32_t range) { // whether the head and range is valid
+//
+//    uint32_t mask = 0b110011 << head; // fill 2x2 block
+//
+//    for (int addr = 0; range; range >>= 2) { // traverse every 2-bits
+//
+//        while (mask >> addr & 0b1) {
+//            ++addr; // search next not filled block
+//        }
+//
+//        switch (range & 0b11) {
+//            case 0b00: // space block
+//            case 0b11: // 1x1 block
+//                mask |= 0b1 << addr; // fill 1x1 block
+//                break;
+//            case 0b10: // 2x1 block
+//                if (addr > 15 || mask >> (addr + 4) & 0b1) { // invalid address
+//                    return false;
+//                }
+//                mask |= 0b10001 << addr; // fill 2x1 block
+//                break;
+//            case 0b01: // 1x2 block
+//                if ((addr & 0b11) == 0b11 || mask >> (addr + 1) & 0b1) { // invalid address
+//                    return false;
+//                }
+//                mask |= 0b11 << addr; // fill 1x2 block
+//                break;
+//        }
+//    }
+//
+//    return true; // valid case
+//
+//}
+
+uint32_t AllCases::check_case(uint32_t head, uint32_t range) { // whether the head and range is valid
+
+    uint32_t num = 1;
+
+    uint32_t mask = 0b110011 << head; // fill 2x2 block
+
+    for (int addr = 0; range; range >>= 2, ++num) { // traverse every 2-bits
+
+        while (mask >> addr & 0b1) {
+            ++addr; // search next not filled block
+        }
+
+        switch (range & 0b11) {
+            case 0b00: // space block
+            case 0b11: // 1x1 block
+                mask |= 0b1 << addr; // fill 1x1 block
+                break;
+            case 0b10: // 2x1 block
+                if (addr > 15 || mask >> (addr + 4) & 0b1) { // invalid address
+                    return num;
+                }
+                mask |= 0b10001 << addr; // fill 2x1 block
+                break;
+            case 0b01: // 1x2 block
+                if ((addr & 0b11) == 0b11 || mask >> (addr + 1) & 0b1) { // invalid address
+                    return num;
+                }
+                mask |= 0b11 << addr; // fill 1x2 block
+                break;
+        }
+    }
+
+    return 0; // valid case
+
+}
+
+#include <iostream>
+
 void AllCases::build_data() { // find all cases
-    for (uint32_t head = 0; head < 16; ++head) { // address of 2x2 block
+
+//    auto range = Common::range_reverse(0xA5740000);
+
+    // A     5     7     4
+    // 10 10 01 01 01 11 01 00
+    //                   !!
+    // search start at
+    // 10 10 01 01 01 11 10 ...
+
+//    auto offset = check_case(0, range);
+//
+//    auto delta = (uint32_t)1 << (32 - check_case(0, range) * 2);
+//
+//    auto next_at_least = Common::range_reverse(range) + delta;
+//
+//    printf("next at least -> %08X\n", next_at_least);
+
+    /// 4258152: 0xA573F000
+    /// 4258153: 0xA5740000
+    /// 4258154: 0xA5743000
+    /// 4258155: 0xA574C000
+    /// 4258156: 0xA5770000
+    /// 4258157: 0xA5780000
+    /// 4258158: 0xA5783000
+    /// 4258159: 0xA578C000
+
+//    auto br = BasicRanges::fetch();
+//
+//    uint32_t ret;
+//    for (auto i = 4258152; i <= 4258159; ++i) {
+//        printf("check: %08X (%d) -> ", Common::range_reverse(br->at(i)), i);
+//
+//        if ((ret = check_case(0, br->at(i))) == 0) {
+//            std::cout << "ok" << std::endl;
+//        } else {
+//            std::cout << "error" << std::endl;
+//
+////            std::cout << "ret = " << ret << std::endl;
+//
+//            auto delta = (uint32_t)1 << (32 - ret * 2);
+//            auto mask = 0xFFFFFFFF << (32 - ret * 2);
+//            auto next_at_least = (Common::range_reverse(br->at(i)) & mask) + delta;
+//
+//            for (;;) {
+//                ++i;
+//                if (Common::range_reverse(br->at(i)) >= next_at_least) {
+//                    break;
+//                }
+//                std::cout << "skip -> next" << std::endl;
+//            }
+//
+//
+//            printf("next at least: %08X\n", next_at_least);
+//
+//        }
+//    }
+
+    /// A    5    7    7    0    0    00
+    /// 1010 0101 0111 0111 0000 0000 ...
+
+//    return;
+
+
+//    for (uint32_t head = 0; head < 16; ++head) { // address of 2x2 block
+    for (uint32_t head = 0; head < 1; ++head) { // address of 2x2 block
         if ((head & 0b11) == 0b11) {
             continue; // invalid 2x2 address
         }
         /// head -> 0/1/2 / 4/5/6 / 8/9/10 / 12/13/14
         data[head].reserve(ALL_CASES_SIZE[head]); // memory pre-allocated
-        for (auto const &range : *BasicRanges::fetch()) { // check base on 2x2 address and range
-            if (Common::check_case(head, range)) {
-                data[head].emplace_back(Common::range_reverse(range)); // found valid case
+//        for (const auto &range : *BasicRanges::fetch()) { // check base on 2x2 address and range
+
+//            printf("%08X -> ", Common::range_reverse(range));
+
+//            if (check_case(head, range)) {
+//                printf("ok\n");
+//                data[head].emplace_back(Common::range_reverse(range)); // found valid case
+//            } else {
+//                printf("error\n");
+//            }
+
+//        }
+
+        uint32_t ret;
+
+        auto br = BasicRanges::fetch();
+
+        for (auto i = 0; i < br->size(); ++i) {
+
+            printf("%d: %08X -> ", i, Common::range_reverse(br->at(i)));
+
+            if ((ret = check_case(0, br->at(i))) == 0) {
+                printf("ok\n");
+            } else {
+                printf("error\n");
+
+                auto delta = (uint32_t)1 << (32 - ret * 2);
+                auto mask = 0xFFFFFFFF << (32 - ret * 2);
+                auto next_at_least = (Common::range_reverse(br->at(i)) & mask) + delta;
+                printf("next at least: %08X\n", next_at_least);
+
+                for (;;) {
+                    ++i;
+                    if (Common::range_reverse(br->at(i)) >= next_at_least) {
+                        break;
+                    }
+                    std::cout << "skip -> next" << std::endl;
+                }
+
             }
+
         }
+
+
+
     }
 }
diff --git a/src/all_cases/all_cases.h b/src/all_cases/all_cases.h
index d8b6b19..4657770 100644
--- a/src/all_cases/all_cases.h
+++ b/src/all_cases/all_cases.h
@@ -24,4 +24,7 @@ private:
     static std::vector<uint32_t> data[16];
 
     static void build_data();
+
+    static uint32_t check_case(uint32_t head, uint32_t range);
+
 };
diff --git a/src/main.cc b/src/main.cc
index 6bf1373..04746e3 100644
--- a/src/main.cc
+++ b/src/main.cc
@@ -241,14 +241,14 @@ int main() {
 
 //    }
 
-
-//    load_ranges();
-    BasicRanges::build();
-    std::cout << "size: " << BasicRanges::fetch()->size() << std::endl;
+//    BasicRanges::build();
+//    std::cout << "size: " << BasicRanges::fetch()->size() << std::endl;
 //    for (const auto &range : *BasicRanges::fetch()) {
 //        printf("%08X\n", range);
 //    }
 
+    AllCases::build();
+
     std::cerr << (clock() - start_time) * 1000 / CLOCKS_PER_SEC << "ms" << std::endl;
 //    std::cerr << (clock() - start_time) * 1000000 / CLOCKS_PER_SEC << "us" << std::endl;
 //    std::cout << "complete benchmark" << std::endl;