diff --git a/constants.c b/constants.c
index 9b69143..b6461aa 100644
--- a/constants.c
+++ b/constants.c
@@ -8,4 +8,5 @@ void main() {
     printf("SOCK_STREAM %d\n", SOCK_STREAM);
     printf("F_GETFL     %d\n", F_GETFL);
     printf("F_SETFL     %d\n", F_SETFL);
+    printf("O_NONBLOCK  %d\n", O_NONBLOCK);
 }
diff --git a/hello.s b/hello.s
index f3a8181..62c7279 100644
--- a/hello.s
+++ b/hello.s
@@ -9,10 +9,14 @@ SYS_ACCEPT      equ 43
 SYS_BIND        equ 49
 SYS_LISTEN      equ 50
 SYS_EXIT        equ 60
+SYS_FCNTL       equ 72
 SYS_UNLINK      equ 87
 STDOUT          equ 1
 AF_UNIX         equ 1
 SOCK_STREAM     equ 1
+F_GETFL         equ 3
+F_SETFL         equ 4
+O_NONBLOCK      equ 2048
 
 SECTION .data
 hello           db "Hello world!", 0x0a
@@ -33,6 +37,24 @@ _start:
     mov rdx, hello_len
     syscall
 
+    call make_server
+    push rax
+    call accept
+    pop r10
+
+exit:
+    mov rax, SYS_EXIT
+    mov rdi, 0
+    syscall
+
+accept:
+    mov rdi, rax
+    mov rax, SYS_ACCEPT
+    mov rsi, 0
+    mov rdx, 0
+    syscall
+    ret
+
 make_server:
     mov rax, SYS_UNLINK
     mov rdi, server_path
@@ -45,6 +67,7 @@ make_server:
     syscall
     push rax
 
+    call nonblocking
     call make_sockaddr
     pop r10
 
@@ -59,18 +82,28 @@ make_server:
     mov rsi, 100
     syscall
 
-    mov rax, SYS_ACCEPT
-    mov rdi, r10
-    mov rsi, 0
-    mov rdx, 0
-    syscall
-    push rax
+    mov rax, r10
+    ret
 
-exit:
-    mov rax, SYS_EXIT
-    pop rdi
+nonblocking:
+    mov r10, rax
+
+    mov rax, SYS_FCNTL
+    mov rdi, r10
+    mov rsi, F_GETFL
     syscall
 
+    mov r11, rax
+    xor r11, O_NONBLOCK
+
+    mov rax, SYS_FCNTL
+    mov rdi, r10
+    mov rsi, F_SETFL
+    mov rdx, r11
+    syscall
+
+    ret
+
 make_sockaddr:
     mov word [sockaddr], AF_UNIX
     mov rax, 0