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nand2tetris-assembler.el
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nand2tetris-assembler.el
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;;; nand2tetris-assembler.el --- Assembler For the Nand2tetris Course
;;; https://www.coursera.org/course/nand2tetris-assembler1
;; Copyright (C) 2015 Diego Berrocal
;; Author: Diego Berrocal <[email protected]>
;; Created: 10 August 2015
;; Keywords: nand2tetris-assembler, hdl
;; Homepage: http://www.github.com/CestDiego/nand2tetris-assembler.el/
;; Version: 1.1.0
;; Package-Requires: ((nand2tetris "1.1.0"))
;; This file is not part of GNU Emacs.
;;; License:
;;
;; This file is NOT part of GNU Emacs.
;;
;; This program is free software; you can redistribute it and/or
;; modify it under the terms of the GNU General Public License
;; as published by the Free Software Foundation; either version 2
;; of the License, or (at your option) any later version.
;;
;; This program is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
;; GNU General Public License for more details.
;;
;;; Commentary:
;; Useful functions to make following the Nand2Tetris course easier.
;; See: https://www.coursera.org/course/nand2tetris-assembler1
;;; Code:
(require 'nand2tetris)
(defconst nand2tetris-assembler--default-symbols-alist
'(("SP" . #x0)
("LCL" . #x1)
("ARG" . #x2)
("THIS" . #x3)
("THAT" . #x4)
("R0" . #x0)
("R1" . #x1)
("R2" . #x2)
("R3" . #x3)
("R4" . #x4)
("R5" . #x5)
("R6" . #x6)
("R7" . #x7)
("R8" . #x8)
("R9" . #x9)
("R10" . #xA)
("R11" . #xB)
("R12" . #xC)
("R13" . #xD)
("R14" . #xE)
("R15" . #xF)
("SCREEN" . #x4000)
("KBD" . #x6000))
"Default alist of Predefined Symbols for the Hack Assembly.
According to http://www.nand2tetris.org/chapters/chapter%2006.pdf")
(defconst nand2tetris-assembler--comp-symbols-alist
'(("0" . "0101010")
("1" . "0111111")
("-1" . "0111010")
("D" . "0001100")
("A" . "0110000")
("M" . "1110000")
("!D" . "0001101")
("!A" . "0110001")
("!M" . "1110001")
("-D" . "0001111")
("-A" . "0110011")
("-M" . "1110011")
("D+1" . "0011111")
("A+1" . "0110111")
("M+1" . "1110111")
("D-1" . "0001110")
("A-1" . "0110010")
("M-1" . "1110010")
("D+A" . "0000010")
("D+M" . "1000010")
("D-A" . "0010011")
("D-M" . "1010011")
("A-D" . "0000111")
("M-D" . "1000111")
("D&A" . "0000000")
("D&M" . "1000000")
("D|A" . "0010101")
("D|M" . "1010101"))
"Computation symbols relation with their binary representation.")
(defconst nand2tetris-assembler--dest-symbols-alist
'(("" . "000")
("M" . "001")
("D" . "010")
("A" . "100")
("AD" . "110")
("MD" . "011")
("AM" . "101")
("AMD" . "111"))
"Destination symbols relation with their binary representation.")
(defconst nand2tetris-assembler--jump-symbols-alist
'(("" . "000")
("JGT" . "001")
("JEQ" . "010")
("JGE" . "011")
("JLT" . "100")
("JNE" . "101")
("JLE" . "110")
("JMP" . "111"))
"Jump symbols relation with their binary representation.")
(defvar-local nand2tetris-assembler--symbols-alist
nand2tetris-assembler--default-symbols-alist
"Le symbols.")
(defun nand2tetris-assembler/read-lines (file)
"Return list of non-double-slash begginging lines in FILE."
(let ((filter-regexp "\s*//.*$"))
(with-temp-buffer
(insert-file-contents file)
(split-string (buffer-string) "\n" t filter-regexp))))
(defvar nand2tetris-assembler--A-instruction-regexp
(rx ?@ (group (+ digit)))
"Regular Expression for an A instruction.")
(defvar nand2tetris-assembler--C-instruction-regexp
(rx
;;Destination regexp
(* space)
(? (seq
(group (* (or "M" "D" "A")))
?=))
;; Computation regexp
(seq (group
(* (or "M" "A" "D" ?+ ?- ?! ?| ?& "1" "0")))
(? (or line-end space "/")))
;; Jump regexp
(? (seq ";"
(group (* word))
(? (or line-end space "/")))))
"Regular Expression for an A instruction.")
(defun nand2tetris-assembler/parser (instruction)
"Provides convenient access to the command’s components (fields and symbols).
In addition, removes all white space and comments in INSTRUCTION."
(cond ((string-match nand2tetris-assembler--A-instruction-regexp instruction)
`("A" . ,(match-string 1 instruction)))
((string-match nand2tetris-assembler--C-instruction-regexp instruction)
`("C" . (("dest" . ,(match-string 1 instruction))
("comp" . ,(match-string 2 instruction))
("jump" . ,(match-string 3 instruction)))))))
(defun nand2tetris-assembler/format-A-instruction (decimal-number)
"Convert DECIMAL-NUMBER to a 16-long string binary representation.
Resulting string has 0-padding if the binary representaton is not
big enough."
(let* ((integer (string-to-number decimal-number))
(binary-string (nand2tetris-assembler/int-to-binary-string integer)))
(if (<= (length binary-string) 16)
(while (not (equal 16 (length binary-string)))
(setq binary-string (concat "0" binary-string)))
(error "The A instruction gave a binary representation bigger than 2e15"))
binary-string))
(defun nand2tetris-assembler/int-to-binary-string (integer)
"Convert INTEGER into it's binary representation.
Borrowed from http://stackoverflow.com/a/20577329"
(let ((res ""))
(while (not (= integer 0))
(setq res (concat (if (= 1 (logand integer 1)) "1" "0") res))
(setq integer (lsh integer nand2tetris-assembler-1)))
(if (string= res "")
(setq res "0"))
res))
(defun nand2tetris-assembler/format-C-instruction (data-alist)
"Return a valid C-Instruction from the fields in DATA-ALIST.
If one field retrieved by DATA-ALIST isn't matched, error is raised."
(let*
((prefix-bits "111")
(dest-symbol (or (cdr (assoc "dest" data-alist)) ""))
(jump-symbol (or (cdr (assoc "jump" data-alist)) ""))
(comp-symbol (or (cdr (assoc "comp" data-alist)) ""))
(dest-bits (cdr (assoc dest-symbol
nand2tetris-assembler--dest-symbols-alist)))
(comp-bits (cdr (assoc comp-symbol
nand2tetris-assembler--comp-symbols-alist)))
(jump-bits (cdr (assoc jump-symbol
nand2tetris-assembler--jump-symbols-alist))))
(unless dest-bits
(error (concat "The Destination Symbol does not"
" match to the predefined symbols: " dest-symbol)))
(unless comp-bits
(error (concat "The Computation Symbol does not"
" match to the predefined symbols: " comp-symbol)))
(unless jump-bits
(error (concat "The Jump Symbol does not"
" match to the predefined symbols: " jump-symbol)))
(concat prefix-bits comp-bits dest-bits jump-bits)))
(defun nand2tetris-assembler/process (instruction)
"Assume INSTRUCTION is valid and output it's binary representation.
Instruction correctness given by
http://www.nand2tetris.org/chapters/chapter%2006.pdf Page 106.
Also the parsed lines do not start with `//' so we can assume it
will only have a instruction and maybe inline comments that are
going to be ignored by the regular expressions."
(let* ((parsed-instruction (nand2tetris-assembler/parser instruction))
(type (car parsed-instruction))
(parsed-data (cdr parsed-instruction)))
(cond
((equal type "A" )
(insert
(nand2tetris-assembler/format-A-instruction parsed-data)))
((equal type "C")
;; (print parsed-data)
(insert
(nand2tetris-assembler/format-C-instruction parsed-data))))
(insert "\n")))
(defconst nand2tetris-assembler--label-regexp
(rx "(" (group (+ (or word ?- ?_ ?. ?$))) ")" )
"Regular Expression that matches the label tags.")
(defconst nand2tetris-assembler--variable-regexp
(rx ?@ (group letter (* (or word ?- ?_ ?. ?$))))
"Regular Expression that matches the variable tags.")
(defun nand2tetris-assembler/digest-labels (lines)
"Read LINES and take away the labels.
The LABELS are stored in `nand2tetris-assembler--symbols-alist'"
(let ((i 0)
(digested-lines '()))
(dolist (line lines digested-lines)
(if (string-match nand2tetris-assembler--label-regexp line)
(let* ((label (match-string 1 line)))
;; Make sure label is not repeated if it is ERROR
;; Make sure this is not final line.
(push `(,label . ,i) nand2tetris-assembler--symbols-alist))
;; Line isn't a label so..
;; Augment the counter
(setq i (+ 1 i))
;; Let the line pass thru
(setq digested-lines (append digested-lines (list line)))))))
(defun nand2tetris-assembler/replace-variables (lines)
"Return a variable/label agnostic INSTRUCTION for each of the LINES.
Use the tables defined in `nand2tetris-assembler--symbols-alist'.
Take into consideration that this table stores integer values, so
that when returning the corresponding instruction we use the
`format' function with the %d escape."
(let ((variable-index 16) ;; Start variables at 16
(instructions '()))
(dolist (line lines instructions)
(if (string-match nand2tetris-assembler--variable-regexp line)
(let* ((variable-name (match-string 1 line))
(value (cdr
(assoc variable-name nand2tetris-assembler--symbols-alist))))
(when (equal "" variable-name)
(error
"In Replacing Variables: variable-name checks empty string"))
(if value
;; There is a variable or label with that name in the alist
(setq instructions (append instructions
(list (format "@%d" value))))
;; We add the variable to the alist, we use the full name instead
;; of the let local variable because otherwise push isn't global.
(push `(,variable-name . ,variable-index) nand2tetris-assembler--symbols-alist)
;; Let's replace it imnediatly so that we don't make another scan
;; of the lines
(setq instructions
(append instructions (list (format "@%d" variable-index))))
;; Increase the counter
(setq variable-index (+ 1 variable-index))))
(setq instructions (append instructions (list line)))))))
(defun nand2tetris-assembler/init ()
"Init function for the Hack Assembly mode."
(interactive)
;; Initialize the symbols alist
(let* ((current-file (buffer-file-name))
(read-lines (nand2tetris-assembler/read-lines current-file))
(digested-lines (nand2tetris-assembler/digest-labels read-lines))
(filename (concat
(file-name-sans-extension buffer-file-name)
".hack"))
(instructions (nand2tetris-assembler/replace-variables digested-lines)))
(with-temp-file filename
(mapcar #'nand2tetris-assembler/process instructions))))
;;; Bindings
(defvar nand2tetris-assembler-mode-map
(let ((map (make-sparse-keymap)))
;;Compile
(define-key map "\C-c\C-c" #'nand2tetris-assembler/init)
map)
"Keymap for `nand2tetris-assembler-mode'.")
;;; Syntax Table
(defconst nand2tetris-assembler-mode-syntax-table
(let ((table (make-syntax-table)))
(modify-syntax-entry ?/ ". 124b" table)
(modify-syntax-entry ?* ". 23" table)
(modify-syntax-entry ?\n "> b" table)
table))
;;; Major Mode
(define-derived-mode nand2tetris-assembler-mode prog-mode
"HACK Assembler"
"Major mode for the HACK Assembler language.
\\{nand2tetris-assembler-mode-map}"
(set (make-local-variable 'comment-start) "// ")
(set (make-local-variable 'comment-start-skip) "//+\\s-*")
;; (set (make-local-variable 'font-lock-defaults)
;; '(nand2tetris-font-lock-keywords nil nil nil nil))
)
;;;###autoload
(add-to-list 'auto-mode-alist
`(,(concat (expand-file-name nand2tetris-core-base-dir) "\.*\\.asm")
. ,#'nand2tetris-assembler-mode))
(provide 'nand2tetris-assembler)
;;; nand2tetris-assembler.el ends here