; This is my emacs mode for coding assembly language that works 
; with the nasm assembler. I originally wrote it to overcome
; some of the things I didn't like in nasm-mode.

; It's licensed under the Gnu General Public License, NO WARRANTY.


(defvar nasm-mode-hook () "Hook run when starting nasm-mode.")
(defvar nasm-mode-map () "Map used by nasm-mode.")
(defvar nasm-mode-syntax-table () "Nasm-mode's syntax table.")

(if (null nasm-mode-map) 
    (progn
      (setq nasm-mode-map (make-sparse-keymap))
      ))

(define-key nasm-mode-map "\C-i" 'tab-to-tab-stop)
(define-key nasm-mode-map "\C-j" 'nasm-newline)
(define-key nasm-mode-map "\C-m" 'nasm-newline)
(define-key nasm-mode-map ";" 'nasm-semicolon)
(define-key nasm-mode-map ":" 'nasm-colon)

(setq nasm-mode-syntax-table (make-syntax-table))
(modify-syntax-entry ?\; "<" nasm-mode-syntax-table)
(modify-syntax-entry ?\n ">" nasm-mode-syntax-table)
(modify-syntax-entry ?\" "\"" nasm-mode-syntax-table)
(modify-syntax-entry ?' "\"" nasm-mode-syntax-table)

(defun nasm-mode ()
  "Major mode for editing nasm assembler source code. It's essentially
a pared-down version of asm-mode, customized by Tom.

\\{nasm-mode-map}"


  (interactive)
  (kill-all-local-variables)

  (setq mode-name "Nasm")
  (setq major-mode 'nasm-mode)
  (setq comment-start ";")
  (set-syntax-table nasm-mode-syntax-table)
  (run-hooks 'nasm-mode-hook)
  (use-local-map nasm-mode-map)
)


(defun nasm-newline ()
  "Inserts linefeed, and then indents to the appropriate point on the 
next time."
  (interactive)
  (if (eolp) (delete-horizontal-space))
  (insert "\n")
  (indent-relative)
)

(defun nasm-semicolon () 
  "Inserts a semicolon in the current buffer, indenting to the next tab
stop if we're not currently at a tab stop."
  (interactive)
  (unless (member (current-column) tab-stop-list)
    (tab-to-tab-stop)
    )
  (insert "; ")
)

(defun nasm-colon () 
  "Handles colons... If it's a label, pushes it to the start of the line,
otherwise just inserts it."
  (interactive)

  (if  
      (save-excursion
	(beginning-of-line)
	(looking-at "[ \t]+\\.*\\sw+$"))
      (progn
	(beginning-of-line)
	(delete-horizontal-space)
	(end-of-line)
	(insert ":")
	(tab-to-tab-stop)
	)
    (insert ":")
    )
  )


(setq nasm-font-lock-keywords (list
      '("^\\w+:" . font-lock-function-name-face)
      '("\t\\w+" . font-lock-keyword-face)
      '(";.*$" . font-lock-comment-face)
      '("\\b[abcd]h\\b" . font-lock-other-emphasized-face)
      '("\\b[abcd]l\\b" . font-lock-other-emphasized-face)
      '("\\be?[abcd]x\\b" . font-lock-other-emphasized-face)
      '("\\b[cdefg]s\\b" . font-lock-other-emphasized-face)
      '("\\b[ds]i\\b" . font-lock-other-emphasized-face)
      '("\\b[bs]p\\b" . font-lock-other-emphasized-face)
      '("\\b[cdefg]s\\b" . font-lock-other-emphasized-face)
))

(put 'nasm-mode 'font-lock-defaults 
     '((nasm-font-lock-keywords) nil nil nil nil))

(setq auto-mode-alist (cons '("\\.asm$" . nasm-mode) auto-mode-alist))