This is Intel i386 or higher asm code version of ntdll.dll The minium cpu req by reactos are : 486. The asm src in this folder need nasm to be compile with. 1. Rename reactos/lib/ntdll/makefile to reactos/lib/ntdll/makefile.c or make a backup up of it. (it contain the C code version of ntdll makefile) 2. Copy reactos/lib/ntdll/nasm/makefile-asm to reactos/lib/ntdll/makefile (it contain the asm verison of ntdll makefile, I need to change some part to get the asm version be in use insted of the c version) 3. Now run reactos/make so u get the asm version of ntdll Hope everyone like this asm optimze version. but for momment are only thing optimze are ntdll/rtl/mem.c ----------------------------------------- RtlCompareMemory RtlCompareMemoryUlong RtlFillMemoryUlong RtlMoveMemory RtlZeroMemory RtlFillMemory (can make it lite faster not maxium optimze yet) ntdll/rtl/RtlRandom.c ----------------------------------------- RtlRandom RtlUniform SavedValue info about ntdll/nasm/fixasm.bat ----------------------------------------- delete all file that are not src or bat file in the folder ntdll/nasm/