diff options
Diffstat (limited to 'binary.lisp')
| -rw-r--r-- | binary.lisp | 103 |
1 files changed, 103 insertions, 0 deletions
diff --git a/binary.lisp b/binary.lisp new file mode 100644 index 0000000..75ca5e9 --- /dev/null +++ b/binary.lisp @@ -0,0 +1,103 @@ +;; -*- 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 converting an addressing mode argument. +(defparameter + *convert-addressing-modes* + '( + (immediate + (lambda (s) + (let ((return-value 0) ; Final return value. + (operand nil)) ; Stores +/- found. + (dotimes (i (length s)) + (cond + ;; Starting hash + ((eq (char s i) #\#) + nil) + ;; Hexadecimal value + ((eq (char s i) #\$) + (progn (incf i) + (setf return-value + (if (not (equal operand nil)) + (funcall operand + return-value + (hex2dec (subseq s i (+ i 2)))) + (hex2dec (subseq s i (+ i 2))))) + (incf i))) + ;; Plus or Minus + ((or (eq (char s i) #\+) + (eq (char s i) #\-)) + (setf operand + (read-from-string (subseq s i (+ i 1))))) + ;; Interpret character + ((and (eq (char s i) #\') + (eq (char s (+ i 2)) #\')) + (progn (incf i) + (setf return-value + (if (not (equal operand nil)) + (funcall operand + return-value + (char-code (char s i))) + (char-code (char s i)))) + (incf i))) + (t (error "Badly formed immediate instruction.")) + )) + (mod return-value 256))) + (absolute + (lambda (s) + (list (hex2dec (subseq s 1 3)) + (hex2dec (subseq s 3 5))))) + (zero-page + (lambda (s) + (list (hex2dec (subseq s 1 3))))) + (implied + (lambda (s) + nil)) + (indirect-absolute + (lambda (s) + (list (hex2dec (subseq s 2 4)) + (hex2dec (subseq s 4 6))))) + (absolute-indexed-x + (lambda (s) + (list (hex2dec (subseq s 1 3)) + (hex2dec (subseq s 3 5))))) + (absolute-indexed-y + (lambda (s) + (list (hex2dec (subseq s 1 3)) + (hex2dec (subseq s 3 5))))) + (zero-page-indexed-x + (lambda (s) + (list (hex2dec (subseq s 1 3))))) + (zero-page-indexed-y + (lambda (s) + (list (hex2dec (subseq s 1 3))))) + (indexed-indirect + (lambda (s) + (list (hex2dec (subseq s 2 4))))) + (indirect-indexed + (lambda (s) + (list (hex2dec (subseq s 2 4))))) + (relative + (lambda (s) + (list (hex2dec (subseq s 1 3)) + (hex2dec (subseq s 3 5))))) + (accumulator + (lambda (s) + nil))))) |