finished 01, now just need to write readme

00/README.md

@@ -25,7 +25,7 @@ it even smaller if you wanted to. Let's take a look at what's inside (`od -t x1
 00 10 00 00 00 00 00 00 48 b8 6d 02 40 00 00 00
 00 00 48 89 c7 31 c0 48 89 c6 48 b8 02 00 00 00
 00 00 00 00 0f 05 48 b8 72 02 40 00 00 00 00 00
-48 89 c7 48 b8 41 00 00 00 00 00 00 00 48 89 c6
+48 89 c7 48 b8 41 02 00 00 00 00 00 00 48 89 c6
 48 b8 ed 01 00 00 00 00 00 00 48 89 c2 48 b8 02
 00 00 00 00 00 00 00 0f 05 48 b8 03 00 00 00 00
 00 00 00 48 89 c7 48 89 c2 48 b8 6a 02 40 00 00
@@ -179,18 +179,19 @@ Now we open our output file:
 
 - `48 b8 72 02 40 00 00 00 00 00` `mov rax, 0x400272`
 - `48 89 c7` `mov rdi, rax`
-- `48 b8 41 00 00 00 00 00 00 00` `mov rax, 0x41`
+- `48 b8 41 02 00 00 00 00 00 00` `mov rax, 0x41`
 - `48 89 c6` `mov rsi, rax`
 - `48 b8 ed 01 00 00 00 00 00 00` `mov rax, 0o755`
 - `48 89 c2` `mov rdx, rax`
 - `48 b8 02 00 00 00 00 00 00 00` `mov rax, 2`
 - `0f 05` `syscall`
 
-In C, this is `open("out00", O_WRONLY|O_CREAT, 0755)`.  This is quite similar
-to our first call, with two important differences: first, we specify `0x41` as
-the second argument. This tells Linux that we are writing to the file
-(`O_WRONLY = 0x01`), and that we want to create it if it doesn't exist
-(`O_CREAT = 0x40`). Secondly, we are setting the third argument this time.  It
+In C, this is `open("out00", O_WRONLY|O_CREAT|O_TRUNC, 0755)`.  This is quite
+similar to our first call, with two important differences: first, we specify
+`0x241` as the second argument. This tells Linux that we are writing to the
+file (`O_WRONLY = 0x01`), that we want to create it if it doesn't exist
+(`O_CREAT = 0x40`), and that we want to delete any previous contents it had
+(`O_TRUNC = 0x200`). Secondly, we are setting the third argument this time.  It
 specifies the permissions our file is created with (`0o755` means user
 read/write/execute, group/other read/execute). This is not very important to
 the actual execution of the program, so don't worry if you don't know what it