➕ Moves from 32 to 64 bit syscalls

main.s

@@ -2,16 +2,17 @@
 
 .text
 _start:
-	movl  $4, %eax   # 4 (code for "write" syscall) -> EAX register
-	movl  $1, %ebx   # 1 (file descriptor for stdout) -> EBX (1st argument to syscall)
-	movl  $msg, %ecx # 32-bit address of msg string -> ECX (2nd argument)
-	movl  $len, %edx # length of msg string -> EDX (3rd arg)
-	int   $0x80      # interrupt with location 0x80 (128), which invokes the kernel's system call procedure
+	mov $1, %rax
+	mov $1, %rdi
+	mov $msg, %rsi
+	mov $len, %rdx
+	syscall
+
+	mov $60, %rax
+	mov $0, %rdi
+	syscall
 
-	movl  $1, %eax   # 1 ("exit") -> EAX
-	movl  $0, %ebx   # 0 (with success) -> EBX
-	int   $0x80      # see previous
 .data
 msg:
-	.ascii  "Hello, world!\n" # inline ascii string
-	len =   . - msg           # assign (current address - address of msg start) to symbol "len"
+	.ascii "Hello, world!\n"
+	len = . - msg