Added comments.

.gitignore

@@ -0,0 +1,3 @@
+# Ignore binaries
+*.o
+helloworld

src/HelloWorld.asm

@@ -1,17 +1,17 @@
 .section .data
     hello:
-        .ascii "Hello, World.\n"
+        .ascii "Hello, World.\n"    # the string
 
 .section .text
     .global _start
 
 _start:
-    mov $1, %rax
-    mov $1, %rdi
-    mov $hello, %rsi
-    mov $14, %rdx
-    syscall
+    mov $1, %rax                    # Define write syscall
+    mov $1, %rdi                    # Define stdout
+    mov $hello, %rsi                # Give string
+    mov $14, %rdx                   # Give size of the string
+    syscall                         # Call the kernel to do work for us
 
-    mov $60, %rax
-    xor %rdi, %rdi
-    syscall
+    mov $60, %rax                   # Define exit syscall
+    xor %rdi, %rdi                  # Give return value
+    syscall                         # Call the kernel to do work for us