#+TITLE: asm layer

#+TAGS: general|imperative|layer|programming

[[file:img/asm.png]]

* Table of Contents                     :TOC_5_gh:noexport:
- [[#description][Description]]
  - [[#features][Features:]]
- [[#install][Install]]
  - [[#layer][Layer]]
  - [[#pdfs][PDFs]]
- [[#key-bindings][Key bindings]]

* Description
This layer adds support for Assembly code. The built-in major mode for
editing assembly code in Emacs is =asm-mode=.

The layer also adds =nasm-mode= for NASM-specific syntax. Although =nasm-mode=
is intended for NASM, it actually works well with other variants of Assembly
in general, and provides Imenu integration so you can jump around with ~SPC s j~.

** Features:
- Improved syntax highlighting.
- Automatic indentation.
- Auto-completion for symbol in opened buffers.
- Look up documentation for current instruction at cursor.
- Imenu integration.

* Install
** Layer
To use this configuration layer, add it to your =~/.spacemacs=. You will need to
add =asm= to the existing =dotspacemacs-configuration-layers= list in this
file.

** PDFs
To look up the x86 instructions, two things are required:
- the =pdftotext= command line tool from Poppler:

  #+BEGIN_SRC sh
    sudo apt-get install poppler-utils
  #+END_SRC

- [[https://software.intel.com/en-us/articles/intel-sdm][Intel® 64 and IA-32 Architectures Software Developer Manuals]]. Any PDF that
  contains the full instruction set reference will work, though volume 2 is the
  best choice for x86-lookup.

Then, set =x86-lookup-pdf= to the location of your PDF document (Tip: If you use
Helm as your completion of choice, you can use ~SPC f f~ to navigate to the
file, and press ~C-c i~ to insert the path). For example, something like this:

#+BEGIN_SRC emacs-lisp
  (setq x86-lookup-pdf "~/64-ia-32-architectures-software-developer-instruction-set-reference-manual-325383.pdf")
#+END_SRC

The first time you launch the command, it can take a while for indexing, this
is a one time operation and the result is cached for later use.

* Key bindings

| Key binding | Description                                        |
|-------------+----------------------------------------------------|
| ~SPC m h h~ | Look up the documentation for instruction at point |
| ~;~         | Insert a comment                                   |

_Note_: Quoted from the docstring of =asm-comment=, the command bound to ~;~:

#+BEGIN_SRC text
  Convert an empty comment to a `larger' kind, or start a new one.
  These are the known comment classes:

     1 -- comment to the right of the code (at the comment-column)
     2 -- comment on its own line, indented like code
     3 -- comment on its own line, beginning at the left-most column.

  Suggested usage:  while writing your code, trigger asm-comment
  repeatedly until you are satisfied with the kind of comment.
#+END_SRC