How are vim macors is displays in the register
===

I found out how handy it is to be able to use macros in VIM. In particular recording with `q` but I'm confused about how to read what is stored in the register I'm recording to.

To take a specific example I use VIM a lot for writing LaTeX documents, and in that connection I have made a macro that puts a `%` at the start of the current line, so that this code is commented out. I did this by recording as follows. I pressed the keys `q u <Home> i % <Esc> q`. Now by pressing `@u` I am able to play that macro, and since I use that one a lot I desided to put it in my `.vimrc` file. I looked at the subject and found out that I have to use `<C-v>` to grab the keystrokes I use, e.g., the escape key. I 

    let @u='^[OHi%^['

where I produced `^OH` with `<C-v> <Home>` and `^[` with `<C-v> <Esc>`. Now when I start VIM the contents of register `u` is `^[OHi%^[`, as it ought to be, but if I just recorded the macro with `q`, then the register would read

    <80>khi%^[

I have tried to understand what this means. It does the same thing, but if I try to write something similar using `<C-v>` after consulting some of the help pages in vim (more precisely `:help key-notation`, `:help i_CTRL-V` and `:help i_CTRL-V_digit`), but I still don't understand it.

My motivation for wanting to understand this is that I would like to be able to read what macro I have recorded does. if I understand how the contents of the register is produced, then I might be able to understand it by producing a similar result. For example if the the macros I recorded followed the same syntax as when using `<C-v>` then I could just check what `<C-v>` plus the most likely keystrokes produced and see which one maches.