diff --git a/.github/workflows/windows.yml b/.github/workflows/windows.yml
index d099290a316..2f8fe2d3be8 100644
--- a/.github/workflows/windows.yml
+++ b/.github/workflows/windows.yml
@@ -119,6 +119,19 @@ jobs:
         Copy-Item -Path "$env:GITHUB_WORKSPACE\swiftshader-install\vulkan-1.dll" -Destination 'build-x64\tests'
         cd build-x64; ctest -C Release --output-on-failure -j 4
 
+    - name: x64-simpleomp
+      run: |
+          mkdir build-x64-simpleomp; cd build-x64-simpleomp
+          cmake -T ${{ matrix.toolset-version }},host=x64 -A x64 -Dprotobuf_DIR="$env:GITHUB_WORKSPACE\protobuf-install\cmake" -DNCNN_SHARED_LIB=OFF -DNCNN_VULKAN=ON -DNCNN_SIMPLEOMP=ON -DNCNN_BUILD_TESTS=ON ..
+          cmake --build . --config Release -j 4
+    - name: x64-simpleomp-test
+      if: matrix.vs-version != 'vs2015' && matrix.vs-version != 'vs2017'
+      run: |
+        echo "[Processor]`nThreadCount=1`n" > build-x64-simpleomp/tests/Release/SwiftShader.ini
+        Copy-Item -Path "$env:GITHUB_WORKSPACE\swiftshader-install\vulkan-1.dll" -Destination 'build-x64-simpleomp\tests'
+        cd build-x64-simpleomp; ctest -C Release --output-on-failure -j 4
+# Copy-Item -Path "build-x64-simpleomp\src\Release\ncnn.dll" -Destination 'build-x64-simpleomp\tests'
+
     - name: x64-sse2
       run: |
         mkdir build-x64-sse2; cd build-x64-sse2
@@ -144,3 +157,7 @@ jobs:
       run: |
         Copy-Item -Path "build-x86\src\Release\ncnn.dll" -Destination 'build-x86\tests'
         cd build-x86; ctest -C Release --output-on-failure -j 4
+
+    
+
+
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 0f32a80c86e..9734b97ac19 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -687,7 +687,7 @@ if(NCNN_VULKAN)
             endif()
         endif()
 
-        if (TARGET glslang AND TARGET SPIRV)
+        if(TARGET glslang AND TARGET SPIRV)
             get_property(glslang_location TARGET glslang PROPERTY LOCATION)
             get_property(SPIRV_location TARGET SPIRV PROPERTY LOCATION)
             message(STATUS "Found glslang: ${glslang_location} (found version \"${glslang_VERSION}\")")
diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 803c34a780d..5aa7206ac8b 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -10,8 +10,8 @@ function(ncnn_src_group ncnn_src_string folder)
     string(REGEX REPLACE "/" "\\\\" _target_folder "${folder}")
 
     foreach(_file IN LISTS ${_ncnn_src_list})
-        source_group ("${_target_folder}" FILES "${_file}")
-    endforeach ()
+        source_group("${_target_folder}" FILES "${_file}")
+    endforeach()
 endfunction()
 
 set(ncnn_SRCS
@@ -215,11 +215,11 @@ endif()
 
 target_include_directories(ncnn
     PUBLIC
-        $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}>
-        $<INSTALL_INTERFACE:include/ncnn>
-        $<BUILD_INTERFACE:${CMAKE_CURRENT_BINARY_DIR}>
+    $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}>
+    $<INSTALL_INTERFACE:include/ncnn>
+    $<BUILD_INTERFACE:${CMAKE_CURRENT_BINARY_DIR}>
     PRIVATE
-        $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/layer>)
+    $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/layer>)
 
 if(NCNN_OPENMP)
     if(NOT NCNN_SIMPLEOMP)
@@ -237,6 +237,8 @@ if(NCNN_OPENMP)
         if(NCNN_SIMPLEOMP)
             if(IOS OR APPLE)
                 target_compile_options(ncnn PRIVATE -Xpreprocessor -fopenmp)
+            elseif(MSVC OR WIN32)
+                target_compile_options(ncnn PRIVATE /openmp)
             else()
                 target_compile_options(ncnn PRIVATE -fopenmp)
             endif()
@@ -262,7 +264,11 @@ if(NCNN_THREADS)
         target_link_libraries(ncnn PUBLIC Threads::Threads)
     endif()
     if(NCNN_SIMPLEOMP OR NCNN_SIMPLESTL)
-        target_link_libraries(ncnn PUBLIC pthread)
+        if(MSVC OR WIN32)
+            message(STATUS "Using Native WIN32 THREAD MODEL")
+        else()
+            target_link_libraries(ncnn PUBLIC pthread)
+        endif()
     endif()
 endif()
 
@@ -398,7 +404,7 @@ if(NCNN_TARGET_ARCH STREQUAL "x86")
         else()
             if(NOT CMAKE_SYSTEM_NAME MATCHES "WASI")
                 target_compile_options(ncnn PRIVATE -msse2 -msse)
-            endif ()
+            endif()
             if(CMAKE_SYSTEM_NAME MATCHES "Emscripten|WASI")
                 target_compile_options(ncnn PRIVATE -msimd128)
             endif()
diff --git a/src/simpleomp.cpp b/src/simpleomp.cpp
index 6de069a9b6f..73719efac79 100644
--- a/src/simpleomp.cpp
+++ b/src/simpleomp.cpp
@@ -61,11 +61,52 @@ extern "C" typedef void (*kmpc_micro_30)(int32_t* gtid, int32_t* tid, void*, voi
 extern "C" typedef void (*kmpc_micro_31)(int32_t* gtid, int32_t* tid, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*);
 #endif // __clang__
 
+#if _WIN32
+extern "C" typedef void (*win_kmpc_micro)(int32_t* gtid, int32_t* tid, ...);
+extern "C" typedef void (*win_kmpc_micro_0)();
+extern "C" typedef void (*win_kmpc_micro_1)(void*);
+extern "C" typedef void (*win_kmpc_micro_2)(void*, void*);
+extern "C" typedef void (*win_kmpc_micro_3)(void*, void*, void*);
+extern "C" typedef void (*win_kmpc_micro_4)(void*, void*, void*, void*);
+extern "C" typedef void (*win_kmpc_micro_5)(void*, void*, void*, void*, void*);
+extern "C" typedef void (*win_kmpc_micro_6)(void*, void*, void*, void*, void*, void*);
+extern "C" typedef void (*win_kmpc_micro_7)(void*, void*, void*, void*, void*, void*, void*);
+extern "C" typedef void (*win_kmpc_micro_8)(void*, void*, void*, void*, void*, void*, void*, void*);
+extern "C" typedef void (*win_kmpc_micro_9)(void*, void*, void*, void*, void*, void*, void*, void*, void*);
+extern "C" typedef void (*win_kmpc_micro_10)(void*, void*, void*, void*, void*, void*, void*, void*, void*, void*);
+extern "C" typedef void (*win_kmpc_micro_11)(void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*);
+extern "C" typedef void (*win_kmpc_micro_12)(void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*);
+extern "C" typedef void (*win_kmpc_micro_13)(void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*);
+extern "C" typedef void (*win_kmpc_micro_14)(void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*);
+extern "C" typedef void (*win_kmpc_micro_15)(void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*);
+extern "C" typedef void (*win_kmpc_micro_16)(void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*);
+extern "C" typedef void (*win_kmpc_micro_17)(void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*);
+extern "C" typedef void (*win_kmpc_micro_18)(void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*);
+extern "C" typedef void (*win_kmpc_micro_19)(void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*);
+extern "C" typedef void (*win_kmpc_micro_20)(void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*);
+extern "C" typedef void (*win_kmpc_micro_21)(void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*);
+extern "C" typedef void (*win_kmpc_micro_22)(void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*);
+extern "C" typedef void (*win_kmpc_micro_23)(void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*);
+extern "C" typedef void (*win_kmpc_micro_24)(void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*);
+extern "C" typedef void (*win_kmpc_micro_25)(void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*);
+extern "C" typedef void (*win_kmpc_micro_26)(void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*);
+extern "C" typedef void (*win_kmpc_micro_27)(void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*);
+extern "C" typedef void (*win_kmpc_micro_28)(void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*);
+extern "C" typedef void (*win_kmpc_micro_29)(void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*);
+extern "C" typedef void (*win_kmpc_micro_30)(void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*);
+extern "C" typedef void (*win_kmpc_micro_31)(void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*, void*);
+#endif // _WIN32
+
 #ifdef __cplusplus
 extern "C" {
 #endif
 
+#ifdef _WIN32
+static BOOL CALLBACK init_g_kmp_global(PINIT_ONCE InitOnce, PVOID Parameter, PVOID* Context);
+#else
 static void init_g_kmp_global();
+#endif // _WIN32
+
 static void* kmp_threadfunc(void* args);
 
 #ifdef __cplusplus
@@ -83,6 +124,11 @@ class KMPTask
     kmpc_micro fn;
     int argc;
     void** argv;
+#elif _WIN32
+    // vcomp abi
+    void (*fn)(void*);
+    int argc;
+    void** argv;
 #else
     // libgomp abi
     void (*fn)(void*);
@@ -210,11 +256,19 @@ class KMPGlobal
 
     void try_init()
     {
+#ifdef _WIN32
+        InitOnceExecuteOnce(&is_initialized, init_g_kmp_global, NULL, NULL);
+#else
         pthread_once(&is_initialized, init_g_kmp_global);
+#endif // _WIN32
     }
 
 public:
+#ifdef _WIN32
+    static INIT_ONCE is_initialized;
+#else
     static pthread_once_t is_initialized;
+#endif // _WIN32
 
     void init()
     {
@@ -248,10 +302,14 @@ class KMPGlobal
                 tasks[i].fn = 0;
                 tasks[i].argc = 0;
                 tasks[i].argv = (void**)0;
+#elif _WIN32
+                tasks[i].fn = 0;
+                tasks[i].argc = 0;
+                tasks[i].argv = (void**)0;
 #else
                 tasks[i].fn = 0;
                 tasks[i].data = 0;
-#endif
+#endif // __clang__
                 tasks[i].num_threads = kmp_max_threads;
                 tasks[i].thread_num = i + 1;
                 tasks[i].num_threads_to_wait = 0;
@@ -288,17 +346,29 @@ class KMPGlobal
 
 } // namespace ncnn
 
+#ifdef _WIN32
+INIT_ONCE ncnn::KMPGlobal::is_initialized = INIT_ONCE_STATIC_INIT;
+#else
 pthread_once_t ncnn::KMPGlobal::is_initialized = PTHREAD_ONCE_INIT;
+#endif // _WIN32
 
 static ncnn::KMPGlobal g_kmp_global;
 
 static ncnn::ThreadLocalStorage tls_num_threads;
 static ncnn::ThreadLocalStorage tls_thread_num;
 
+#ifdef _WIN32
+static BOOL CALLBACK init_g_kmp_global(PINIT_ONCE InitOnce, PVOID Parameter, PVOID* Context)
+{
+    g_kmp_global.init();
+    return TRUE;
+}
+#else
 static void init_g_kmp_global()
 {
     g_kmp_global.init();
 }
+#endif // _WIN32
 
 #ifdef __cplusplus
 extern "C" {
@@ -456,6 +526,10 @@ static int kmp_invoke_microtask(kmpc_micro fn, int gtid, int tid, int argc, void
 }
 #endif // __clang__
 
+#if _WIN32
+void CDECL _vcomp_fork_call_wrapper(void* wrapper, int nargs, void** args);
+#endif // _WIN32
+
 static void* kmp_threadfunc(void* args)
 {
 #if __clang__
@@ -479,6 +553,8 @@ static void* kmp_threadfunc(void* args)
 
 #if __clang__
         kmp_invoke_microtask(task->fn, task->thread_num, tid, task->argc, task->argv);
+#elif _WIN32
+        _vcomp_fork_call_wrapper(task->fn, task->argc, task->argv);
 #else
         task->fn(task->data);
 #endif
@@ -650,8 +726,305 @@ void __kmpc_for_static_fini(void* /*loc*/, int32_t gtid)
     // NCNN_LOGE("__kmpc_for_static_fini");
     (void)gtid;
 }
-#else  // __clang__
+#elif _WIN32 // __clang__
+int CDECL omp_in_parallel(void)
+{
+    // NCNN_LOGE("omp_in_parallel() is called!");
+    return TRUE;
+}
+void CDECL _vcomp_set_num_threads(int num_threads)
+{
+    // NCNN_LOGE("_vcomp_set_num_threads(%d)\n", num_threads);
+    if (num_threads >= 1)
+        omp_set_num_threads(num_threads);
+}
+void CDECL _vcomp_fork_call_wrapper(void* wrapper, int nargs, void** args)
+{
+    switch (nargs)
+    {
+    case 0:
+        (*(win_kmpc_micro_0)wrapper)();
+        break;
+    case 1:
+        (*(win_kmpc_micro_1)wrapper)(args[0]);
+        break;
+    case 2:
+        (*(win_kmpc_micro_2)wrapper)(args[0], args[1]);
+        break;
+    case 3:
+        (*(win_kmpc_micro_3)wrapper)(args[0], args[1], args[2]);
+        break;
+    case 4:
+        (*(win_kmpc_micro_4)wrapper)(args[0], args[1], args[2], args[3]);
+        break;
+    case 5:
+        (*(win_kmpc_micro_5)wrapper)(args[0], args[1], args[2], args[3], args[4]);
+        break;
+    case 6:
+        (*(win_kmpc_micro_6)wrapper)(args[0], args[1], args[2], args[3], args[4], args[5]);
+        break;
+    case 7:
+        (*(win_kmpc_micro_7)wrapper)(args[0], args[1], args[2], args[3], args[4], args[5], args[6]);
+        break;
+    case 8:
+        (*(win_kmpc_micro_8)wrapper)(args[0], args[1], args[2], args[3], args[4], args[5], args[6], args[7]);
+        break;
+    case 9:
+        (*(win_kmpc_micro_9)wrapper)(args[0], args[1], args[2], args[3], args[4], args[5], args[6], args[7], args[8]);
+        break;
+    case 10:
+        (*(win_kmpc_micro_10)wrapper)(args[0], args[1], args[2], args[3], args[4], args[5], args[6], args[7], args[8], args[9]);
+        break;
+    case 11:
+        (*(win_kmpc_micro_11)wrapper)(args[0], args[1], args[2], args[3], args[4], args[5], args[6], args[7], args[8], args[9], args[10]);
+        break;
+    case 12:
+        (*(win_kmpc_micro_12)wrapper)(args[0], args[1], args[2], args[3], args[4], args[5], args[6], args[7], args[8], args[9], args[10], args[11]);
+        break;
+    case 13:
+        (*(win_kmpc_micro_13)wrapper)(args[0], args[1], args[2], args[3], args[4], args[5], args[6], args[7], args[8], args[9], args[10], args[11], args[12]);
+        break;
+    case 14:
+        (*(win_kmpc_micro_14)wrapper)(args[0], args[1], args[2], args[3], args[4], args[5], args[6], args[7], args[8], args[9], args[10], args[11], args[12], args[13]);
+        break;
+    case 15:
+        (*(win_kmpc_micro_15)wrapper)(args[0], args[1], args[2], args[3], args[4], args[5], args[6], args[7], args[8], args[9], args[10], args[11], args[12], args[13], args[14]);
+        break;
+    case 16:
+        (*(win_kmpc_micro_16)wrapper)(args[0], args[1], args[2], args[3], args[4], args[5], args[6], args[7], args[8], args[9], args[10], args[11], args[12], args[13], args[14], args[15]);
+        break;
+    case 17:
+        (*(win_kmpc_micro_17)wrapper)(args[0], args[1], args[2], args[3], args[4], args[5], args[6], args[7], args[8], args[9], args[10], args[11], args[12], args[13], args[14], args[15], args[16]);
+        break;
+    case 18:
+        (*(win_kmpc_micro_18)wrapper)(args[0], args[1], args[2], args[3], args[4], args[5], args[6], args[7], args[8], args[9], args[10], args[11], args[12], args[13], args[14], args[15], args[16], args[17]);
+        break;
+    case 19:
+        (*(win_kmpc_micro_19)wrapper)(args[0], args[1], args[2], args[3], args[4], args[5], args[6], args[7], args[8], args[9], args[10], args[11], args[12], args[13], args[14], args[15], args[16], args[17], args[18]);
+        break;
+    case 20:
+        (*(win_kmpc_micro_20)wrapper)(args[0], args[1], args[2], args[3], args[4], args[5], args[6], args[7], args[8], args[9], args[10], args[11], args[12], args[13], args[14], args[15], args[16], args[17], args[18], args[19]);
+        break;
+    case 21:
+        (*(win_kmpc_micro_21)wrapper)(args[0], args[1], args[2], args[3], args[4], args[5], args[6], args[7], args[8], args[9], args[10], args[11], args[12], args[13], args[14], args[15], args[16], args[17], args[18], args[19], args[20]);
+        break;
+    case 22:
+        (*(win_kmpc_micro_22)wrapper)(args[0], args[1], args[2], args[3], args[4], args[5], args[6], args[7], args[8], args[9], args[10], args[11], args[12], args[13], args[14], args[15], args[16], args[17], args[18], args[19], args[20], args[21]);
+        break;
+    case 23:
+        (*(win_kmpc_micro_23)wrapper)(args[0], args[1], args[2], args[3], args[4], args[5], args[6], args[7], args[8], args[9], args[10], args[11], args[12], args[13], args[14], args[15], args[16], args[17], args[18], args[19], args[20], args[21], args[22]);
+        break;
+    case 24:
+        (*(win_kmpc_micro_24)wrapper)(args[0], args[1], args[2], args[3], args[4], args[5], args[6], args[7], args[8], args[9], args[10], args[11], args[12], args[13], args[14], args[15], args[16], args[17], args[18], args[19], args[20], args[21], args[22], args[23]);
+        break;
+    case 25:
+        (*(win_kmpc_micro_25)wrapper)(args[0], args[1], args[2], args[3], args[4], args[5], args[6], args[7], args[8], args[9], args[10], args[11], args[12], args[13], args[14], args[15], args[16], args[17], args[18], args[19], args[20], args[21], args[22], args[23], args[24]);
+        break;
+    case 26:
+        (*(win_kmpc_micro_26)wrapper)(args[0], args[1], args[2], args[3], args[4], args[5], args[6], args[7], args[8], args[9], args[10], args[11], args[12], args[13], args[14], args[15], args[16], args[17], args[18], args[19], args[20], args[21], args[22], args[23], args[24], args[25]);
+        break;
+    case 27:
+        (*(win_kmpc_micro_27)wrapper)(args[0], args[1], args[2], args[3], args[4], args[5], args[6], args[7], args[8], args[9], args[10], args[11], args[12], args[13], args[14], args[15], args[16], args[17], args[18], args[19], args[20], args[21], args[22], args[23], args[24], args[25], args[26]);
+        break;
+    case 28:
+        (*(win_kmpc_micro_28)wrapper)(args[0], args[1], args[2], args[3], args[4], args[5], args[6], args[7], args[8], args[9], args[10], args[11], args[12], args[13], args[14], args[15], args[16], args[17], args[18], args[19], args[20], args[21], args[22], args[23], args[24], args[25], args[26], args[27]);
+        break;
+    case 29:
+        (*(win_kmpc_micro_29)wrapper)(args[0], args[1], args[2], args[3], args[4], args[5], args[6], args[7], args[8], args[9], args[10], args[11], args[12], args[13], args[14], args[15], args[16], args[17], args[18], args[19], args[20], args[21], args[22], args[23], args[24], args[25], args[26], args[27], args[28]);
+        break;
+    case 30:
+        (*(win_kmpc_micro_30)wrapper)(args[0], args[1], args[2], args[3], args[4], args[5], args[6], args[7], args[8], args[9], args[10], args[11], args[12], args[13], args[14], args[15], args[16], args[17], args[18], args[19], args[20], args[21], args[22], args[23], args[24], args[25], args[26], args[27], args[28], args[29]);
+        break;
+    case 31:
+        (*(win_kmpc_micro_31)wrapper)(args[0], args[1], args[2], args[3], args[4], args[5], args[6], args[7], args[8], args[9], args[10], args[11], args[12], args[13], args[14], args[15], args[16], args[17], args[18], args[19], args[20], args[21], args[22], args[23], args[24], args[25], args[26], args[27], args[28], args[29], args[30]);
+        break;
+    default:
+        // this line should not be touched
+        break;
+    }
+}
+
+void CDECL _vcomp_for_static_simple_init(unsigned int first, unsigned int last, int step,
+        BOOL increment, unsigned int* begin, unsigned int* end)
+{
+    unsigned int iterations, per_thread, remaining;
+    int num_threads = omp_get_num_threads();
+    int thread_num = omp_get_thread_num();
+    // NCNN_LOGE("inside _vcomp_for_static_simple_init(), the thread_num is %d", thread_num);
+
+    if (num_threads == 1)
+    {
+        *begin = first;
+        *end = last;
+        return;
+    }
+
+    if (step <= 0)
+    {
+        *begin = 0;
+        *end = increment ? -1 : 1;
+        return;
+    }
+
+    if (increment)
+        iterations = 1 + (last - first) / step;
+    else
+    {
+        iterations = 1 + (first - last) / step;
+        step *= -1;
+    }
+
+    per_thread = iterations / num_threads;
+    remaining = iterations - per_thread * num_threads;
+
+    if (thread_num < remaining)
+        per_thread++;
+    else if (per_thread)
+        first += remaining * step;
+    else
+    {
+        *begin = first;
+        *end = first - step;
+        return;
+    }
+
+    *begin = first + per_thread * thread_num * step;
+    *end = *begin + (per_thread - 1) * step;
+}
 
+void CDECL _vcomp_for_static_simple_init_i8(ULONG64 first, ULONG64 last, LONG64 step,
+        BOOL increment, ULONG64* begin, ULONG64* end)
+{
+    ULONG64 iterations, per_thread, remaining;
+    int num_threads = omp_get_num_threads();
+    int thread_num = omp_get_thread_num();
+
+    if (num_threads == 1)
+    {
+        *begin = first;
+        *end = last;
+        return;
+    }
+
+    if (step <= 0)
+    {
+        *begin = 0;
+        *end = increment ? -1 : 1;
+        return;
+    }
+
+    if (increment)
+        iterations = 1 + (last - first) / step;
+    else
+    {
+        iterations = 1 + (first - last) / step;
+        step *= -1;
+    }
+
+    per_thread = iterations / num_threads;
+    remaining = iterations - per_thread * num_threads;
+
+    if (thread_num < remaining)
+        per_thread++;
+    else if (per_thread)
+        first += remaining * step;
+    else
+    {
+        *begin = first;
+        *end = first - step;
+        return;
+    }
+
+    *begin = first + per_thread * thread_num * step;
+    *end = *begin + (per_thread - 1) * step;
+}
+
+void CDECL _vcomp_for_static_end(void)
+{
+    // NCNN_LOGE("MSVC _vcomp_for_static_end() is called!");
+    /* nothing to do here */
+}
+
+// this func will be called when cl.exe encounters a parallel region
+void WINAPIV _vcomp_fork(BOOL ifval, int nargs, void* wrapper, ...)
+{
+    g_kmp_global.try_init();
+
+    int num_threads = omp_get_num_threads();
+
+    // for nested parallel region feature, not supported here
+    if (!ifval)
+        num_threads = 1;
+
+    // build argv
+    void* argv[32];
+    {
+        va_list ap;
+        va_start(ap, wrapper);
+        for (int i = 0; i < nargs; i++)
+            argv[i] = va_arg(ap, void*);
+        va_end(ap);
+    }
+
+    if (num_threads == 0)
+    {
+        num_threads = omp_get_max_threads();
+    }
+
+    if (g_kmp_global.kmp_max_threads == 1 || num_threads == 1)
+    {
+        for (unsigned i = 0; i < num_threads; i++)
+        {
+            tls_num_threads.set(reinterpret_cast<void*>((size_t)num_threads));
+            tls_thread_num.set(reinterpret_cast<void*>((size_t)i));
+
+            _vcomp_fork_call_wrapper(wrapper, nargs, argv);
+        }
+
+        return;
+    }
+
+    int num_threads_to_wait = num_threads - 1;
+    ncnn::Mutex finish_lock;
+    ncnn::ConditionVariable finish_condition;
+
+    // TODO portable stack allocation
+    ncnn::KMPTask* tasks = (ncnn::KMPTask*)alloca((num_threads - 1) * sizeof(ncnn::KMPTask));
+    for (int i = 0; i < num_threads - 1; i++)
+    {
+        tasks[i].fn = (void (*)(void*))wrapper;
+        tasks[i].argc = nargs;
+        tasks[i].argv = (void**)argv;
+        tasks[i].num_threads = num_threads;
+        tasks[i].thread_num = i + 1;
+        tasks[i].num_threads_to_wait = &num_threads_to_wait;
+        tasks[i].finish_lock = &finish_lock;
+        tasks[i].finish_condition = &finish_condition;
+    }
+
+    // dispatch 1 ~ num_threads
+    g_kmp_global.kmp_task_queue->dispatch(tasks, num_threads - 1);
+
+    // dispatch 0
+    {
+        tls_num_threads.set(reinterpret_cast<void*>((size_t)num_threads));
+        tls_thread_num.set(reinterpret_cast<void*>((size_t)0));
+
+        _vcomp_fork_call_wrapper(wrapper, nargs, argv);
+    }
+
+    // wait for finished
+    {
+        finish_lock.lock();
+        if (num_threads_to_wait != 0)
+        {
+            finish_condition.wait(finish_lock);
+        }
+        finish_lock.unlock();
+    }
+}
+
+#else
 static ncnn::ThreadLocalStorage tls_parallel_context;
 
 struct parallel_context
@@ -661,11 +1034,9 @@ struct parallel_context
     ncnn::ConditionVariable finish_condition;
     ncnn::KMPTask* tasks;
 };
-
 void GOMP_parallel_start(void (*fn)(void*), void* data, unsigned num_threads)
 {
     g_kmp_global.try_init();
-
     // NCNN_LOGE("GOMP_parallel_start %p %p %u", fn, data, num_threads);
     if (num_threads == 0)
     {
@@ -794,6 +1165,7 @@ void GOMP_parallel(void (*fn)(void*), void* data, unsigned num_threads, unsigned
         finish_lock.unlock();
     }
 }
+
 #endif // __clang__
 
 #ifdef __cplusplus