3 files changed, 22 insertions, 20 deletions

diff --git a/README.md b/README.md
index 338a280..64871b5 100644
--- a/README.md
+++ b/README.md
@@ -64,9 +64,9 @@ can be used to build the basic shell, while
 Builds and runs the unit tests. See `build.bat help` for a list of
 all available options.
 
-Note: At the moment certain optimizations, such as multithreading and
-advanced CPU instructions, are not supported on Windows.
-Work is ongoing to improve Windows support.
+Note: The build script for Windows does not support all the options
+available with build.sh. If you want to tune the build options, you'll
+have to manually edit the build script.
 
 ## Running tests
 
diff --git a/build.bat b/build.bat
index 91cc4db..b082e03 100644
--- a/build.bat
+++ b/build.bat
@@ -9,15 +9,25 @@ if [%1]==[/d] (
 

 SET CC=clang

 SET CXX=clang++

-SET ARCH=PORTABLE

 SET THREADS=16

 SET SANITIZE=

 

-:: TODO depends on ARCH variable

-SET ARCHOPTS=

-:: TODO depends on SANITIZE variable

-SET DFLAGS=-g3 -DDEBUG

+SET ARCH=PORTABLE

+clang -march=native -dM -E - < NUL | findstr /C:"__AVX2__" >NUL 2>&1

+if %ERRORLEVEL% EQU 0 (

+    SET ARCH=AVX2

+    SET ARCHOPTS=-mavx2

+    goto :ArchDone

+)

+clang -march=native -dM -E - < NUL | findstr /C:"__ARM_NEON" >NUL 2>&1

+if %ERRORLEVEL% EQU 0 (

+    SET ARCH=NEON

+    goto :ArchDone

+)

+:ArchDone

+

 

+SET DFLAGS=-g3 -DDEBUG

 SET WARNINGS=-Wno-deprecated-declarations

 SET VARIABLES=-DTHREADS=%THREADS% -D%ARCH%

 SET OFLAGS=-O3

diff --git a/src/utils/prefetch.h b/src/utils/prefetch.h
index 89b14e8..a2c41ef 100644
--- a/src/utils/prefetch.h
+++ b/src/utils/prefetch.h
@@ -1,15 +1,7 @@
-#if defined(AVX2)
-
-#define prefetch(a, i) _mm_prefetch(a+i, _MM_HINT_T0)
-
-#else
 #if defined(__GNUC__) || defined(__clang__)
-
-#define prefetch(a, i) __builtin_prefetch(a+i, 0, 0)
-
+    #define prefetch(a, i) __builtin_prefetch(a+i, 0, 0)
+#elif defined(AVX2)
+    #define prefetch(a, i) _mm_prefetch((char *)(a+i), _MM_HINT_T0)
 #else
-
-#define prefetch(a, i) (void)i
-
-#endif
+    #define prefetch(a, i) (void)i
 #endif