diff --git a/arch/x86_64.c b/arch/x86_64.c
index 70f2589..1212137 100644
--- a/arch/x86_64.c
+++ b/arch/x86_64.c
@@ -55,7 +55,7 @@ uint32_t fork() {
 int32_t openat(int32_t fd, const char* filename, uint32_t flags, uint32_t mode) {
   int32_t file;
   asm volatile (
-      "mov %%r10, %5\n"
+      "mov %5, %%r10\n"
       "syscall\n"
       : "=a"(file)
       : "a"(SYS_OPENAT), "D"(fd), "S"(filename), "d"(flags), "r"((uint64_t)mode)  // RDI, RSI, RDX are used in x86-64 for write args