diff --git a/.appveyor.yml b/.appveyor.yml
index 880b8e1..10581fd 100644
--- a/.appveyor.yml
+++ b/.appveyor.yml
@@ -34,6 +34,10 @@ build_script:
 
 test_script:
   - nimble test
+  - IF "%PLATFORM%" == "x86" CALL "C:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\vcvarsall.bat" x86
+  - IF "%PLATFORM%" == "x64" CALL "C:\Program Files\Microsoft SDKs\Windows\v7.1\Bin\SetEnv.cmd" /x64
+  - IF "%PLATFORM%" == "x64" CALL "C:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\vcvarsall.bat" x86_amd64
+  - nimble testvcc
 
 deploy: off
 
diff --git a/.gitignore b/.gitignore
index 739a54a..ff45144 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1 +1,2 @@
 nimcache
+*.exe
diff --git a/stew.nimble b/stew.nimble
index 8b14c48..b00fb2b 100644
--- a/stew.nimble
+++ b/stew.nimble
@@ -12,3 +12,7 @@ requires "nim >= 1.2.0"
 task test, "Run all tests":
   exec "nim c -r --threads:off tests/all_tests"
   exec "nim c -r --threads:on -d:nimTypeNames tests/all_tests"
+
+task testvcc, "Run all tests with vcc compiler":
+  exec "nim c -r --cc:vcc --threads:off tests/all_tests"
+  exec "nim c -r --cc:vcc --threads:on -d:nimTypeNames tests/all_tests"
diff --git a/stew/bitops2.nim b/stew/bitops2.nim
index 8818599..58dc896 100644
--- a/stew/bitops2.nim
+++ b/stew/bitops2.nim
@@ -253,12 +253,12 @@ elif defined(vcc) and useBuiltins:
 
   template checkedScan(fnc: untyped, x: typed, def: typed): int =
     var index{.noinit.}: culong
-    if fnc(index.addr, v) == 0: def
+    if fnc(index.addr, v).int == 0: def
     else: index.int
 
   template bitScan(fnc: untyped, x: typed): int =
     var index{.noinit.}: culong
-    if fnc(index.addr, v) == 0: 0
+    if fnc(index.addr, v).int == 0: 0
     else: index.int
 
   func countOnesBuiltin(v: uint8|uint16|uint32): int = builtin_popcnt32(v.uint32).int
@@ -266,8 +266,8 @@ elif defined(vcc) and useBuiltins:
     when arch64:
       builtin_popcnt64(v).int
     else:
-      builtin_popcnt32((v and 0xFFFFFFFF'u64).uint32).int +
-        builtin_popcnt32((v shr 32'u64).uint32).int
+      builtin_popcnt32((v and 0xFFFFFFFF'u64).cint).int +
+        builtin_popcnt32((v shr 32'u64).cint).int
 
   func firstOneBuiltin(v: uint8|uint16|uint32): int =
     1 + checkedScan(bitScanForward, v.culong, -1)
diff --git a/tests/nim.cfg b/tests/nim.cfg
new file mode 100644
index 0000000..619bfaf
--- /dev/null
+++ b/tests/nim.cfg
@@ -0,0 +1,4 @@
+vcc.exe = "cl.exe"
+vcc.cpp.exe = "cl.exe"
+vcc.linkerexe = "cl.exe"
+vcc.cpp.linkerexe = "cl.exe"
\ No newline at end of file