grammar.lisp -> syntax.lisp, added attribute pass and word rule

1 files changed, 141 insertions, 0 deletions

diff --git a/syntax.lisp b/syntax.lisp
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+;; -*- mode: common-lisp -*-
+#|
+clasm-6502: An assembler for the 6502 written in Common Lisp.
+Copyright (C) 2024  Aleksei Eaves
+
+This library is free software; you can redistribute it and/or
+modify it under the terms of the GNU Lesser General Public
+License as published by the Free Software Foundation; either
+version 2.1 of the License, or (at your option) any later version.
+
+This library 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
+Lesser General Public License for more details.
+
+You should have received a copy of the GNU Lesser General Public
+License along with this library; if not, write to the Free Software
+Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+|#
+
+;; Rules for the interpretation of lines.
+(defparameter
+ *line-syntax*
+ '(
+   (label
+	(lambda (l)
+	  (and (eq (last-char (first l)) #\:)
+		   (eq (length l) 1))))
+   (label-instruction
+	(lambda (l)
+	  (and (eq (last-char (first l)) #\:)
+		   (member (read-from-string (second l)) *opcodes*))))
+   (attribute
+	(lambda (l)
+	  (and (equal (char (first l) 0) #\.)
+		   (not (equal (first l) ".WORD")))))
+   (word
+	(lambda (l)
+	  (and (equal (char (first l) 0) #\.)
+		   (equal (first l) ".WORD"))))
+   (instruction
+	(lambda (l)
+	  (member (read-from-string (first l)) *opcodes*)))
+   (macro
+	(lambda (l)
+	  (equal (second l) "=")))   
+   (unknown
+	(lambda (l)
+	  t))))
+
+;; Rules for identifying addressing modes.
+(defparameter
+ *addressing-modes-syntax*
+ '((immediate ; #?? ... more complex syntax rules for later
+	(lambda (s)
+	  (eq "#" (subseq s 0 1))))
+   (absolute ;"$????"
+	(lambda (s)
+	  (and
+	   (equal (length s) 5)
+	   (equal "$" (subseq s 0 1))
+	   (hexd? (subseq s 1 5)))))
+   (zero-page ;"$??"
+	(lambda (s)
+	  (and
+	   (equal (length s) 3)
+	   (equal "$" (subseq s 0 1))
+	   (hexd? (subseq s 1 3)))))
+   (implied nil)
+   (indirect-absolute ;($????)
+	(lambda (s)
+	  (and
+	   (equal (length s) 7)
+	   (equal "($" (subseq s 0 2))
+	   (hexd? (subseq s 1 5))
+	   (equal ")" (subseq s 5 6)))))
+   (absolute-indexed-x ;"$????,X"
+	(lambda (s)
+	  (and
+	   (equal (length s) 7)
+	   (equal "$" (subseq s 0 1))
+	   (hexd? (subseq s 1 5))
+	   (equal ",X" (subseq s 5 7)))))
+   (absolute-indexed-y ;"$????,Y"
+	(lambda (s)
+	  (and
+	   (equal (length s) 7)
+	   (equal "$" (subseq s 0 1))
+	   (hexd? (subseq s 1 5))
+	   (equal ",Y" (subseq s 5 7)))))
+   (zero-page-indexed-x ;"$??,X"
+	(lambda (s)
+	  (and
+	   (equal (length s) 5)
+	   (equal (subseq s 0 1) "$")
+	   (hexd? (subseq s 1 3))
+	   (equal (subseq s 3 5) ",X"))))
+   (zero-page-indexed-y ;"$??,Y"
+	(lambda (s)
+	  (and
+	   (equal (length s) 5)
+	   (equal (subseq s 0 1) "$")
+	   (hexd? (subseq s 1 3))
+	   (equal (subseq s 3 5) ",Y"))))
+   (indexed-indirect ;"($??,X)"
+	(lambda (s)
+	  (and
+	   (equal (length s) 7)
+	   (equal (subseq s 0 2) "($")
+	   (hexd? (subseq s 2 4))
+	   (equal (subseq s 4 7) ",X)"))))
+   (indirect-indexed ;"($??),Y"
+	(lambda (s)
+	  (and
+	   (equal (length s) 7)
+	   (equal (subseq s 0 2) "($")
+	   (hexd? (subseq s 2 4))
+	   (equal (subseq s 4 7) "),Y"))))
+   ;;How to fix that relative and absolute are the same rule?
+   ;;A check upstream would suffice.
+   (relative ;"$????"
+	(lambda (s)
+	  (and
+	   (equal (length s) 5)
+	   (equal (subseq s 0 1) "$")
+	   (hexd? (subseq s 1 5)))))
+   (accumulator ;"A"
+	(lambda (s)
+	  (and
+	   (equal (length s) 1)
+	   (equal "A" (subseq s 0 1)))))))
+
+(defun syntax-rule (line list)
+  "Apply a syntax rule against a delimited line from a program."
+  (dolist (i (extract-keys list))
+	(let ((z (funcall (eval (cadr (assoc i list)))
+					  line)))
+	  (if (not (equal
+				z nil))
+		  (return i)
+		  nil))))