;; -*- mode: common-lisp -*-
;; 6502.lisp
;; Contains data structures specific to the 6502 system.
#|
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
|#

;;; List of addressing modes and their length.
(defparameter
 *addressing-mode-lengths*
 '((immediate           2)
   (absolute            3)
   (zero-page           2)
   (implied             1)
   (indirect-absolute   3)
   (absolute-indexed-x  3)
   (absolute-indexed-y  3)
   (zero-page-indexed-x 2)
   (zero-page-indexed-y 2)
   (indexed-indirect    2)
   (indirect-indexed    2)
   (relative            2)
   (accumulator         1)))

;; Generated list of addressing modes.
(defparameter
 *addressing-modes*
 (extract-keys *addressing-mode-lengths*))

;;; Instructions, with decimal opcode and
;;; addressing modes.
(defparameter
 *instructions*
 ;; Load & Store
 '((LDA 169 (immediate
			 absolute
			 zero-page
			 absolute-indexed-x
			 absolute-indexed-y
			 zero-page-indexed-x
			 indexed-indirect
			 indirect-indexed))
   (LDX 162 (immediate
			 zero-page
			 zero-page-indexed-y
			 absolute
			 absolute-indexed-y))
   (LDY 160 (immediate
			 zero-page
			 zero-page-indexed-x
			 absolute
			 absolute-indexed-x))
   (STA 137 (absolute
			 zero-page
			 absolute-indexed-x
			 absolute-indexed-y
			 zero-page-indexed-x
			 indexed-indirect
			 indirect-indexed))
   (STX 130 (zero-page
			 zero-page-indexed-y
			 absolute))
   (STY 128 (zero-page
			 zero-page-indexed-x
			 absolute))
   ;;Arithmetic
   (ADC 105 (immediate
			 absolute
			 zero-page
			 absolute-indexed-x
			 absolute-indexed-y
			 zero-page-indexed-x
			 indexed-indirect
			 indirect-indexed))
   (SBC 233 (immediate
			 absolute
			 zero-page
			 absolute-indexed-x
			 absolute-indexed-y
			 zero-page-indexed-x
			 indexed-indirect
			 indirect-indexed))
   ;;Increment & Decrement
   (INC 226 (zero-page
			 zero-page-indexed-x
			 absolute
			 absolute-indexed-x))
   (INX 232 (implied))
   (INY 200 (implied))
   (DEC 194 (zero-page
			 zero-page-indexed-x
			 absolute
			 absolute-indexed-x))
   (DEX 202 (implied))
   (DEY 136 (implied))
   ;; Logical
   (AND  41 (immediate
			 absolute
			 zero-page
			 absolute-indexed-x
			 absolute-indexed-y
			 zero-page-indexed-x
			 indexed-indirect
			 indirect-indexed))
   (ORA   9 (immediate
			 absolute
			 zero-page
			 absolute-indexed-x
			 absolute-indexed-y
			 zero-page-indexed-x
			 indexed-indirect
			 indirect-indexed))
   (EOR  73 (immediate
			 absolute
			 zero-page
			 absolute-indexed-x
			 absolute-indexed-y
			 zero-page-indexed-x
			 indexed-indirect
			 indirect-indexed))
   ;; Jump, Branch, Compare
   (JMP  72 (absolute
			 indirect-absolute))
   (BCC 144 (relative))
   (BCS 176 (relative))
   (BEQ 240 (relative))
   (BNE 208 (relative))
   (BMI  48 (relative))
   (BPL  16 (relative))
   (BVS 112 (relative))
   (BVC  80 (relative))
   (CMP 201 (immediate
			 absolute
			 zero-page
			 absolute-indexed-x
			 absolute-indexed-y
			 zero-page-indexed-x
			 indexed-indirect
			 indirect-indexed))
   (CPX 224 (immediate
			 zero-page
			 absolute))
   (CPY 192 (immediate
			 zero-page
			 absolute))
   (BIT  32 (zero-page
			 absolute))
   ;; Shift & Rotate
   (ASL  10 (accumulator
			 zero-page
			 zero-page-indexed-x
			 absolute
			 absolute-indexed-x))
   (LSR  74 (accumulator
			 zero-page
			 zero-page-indexed-x
			 absolute
			 absolute-indexed-x))
   (ROL  42 (accumulator
			 zero-page
			 zero-page-indexed-x
			 absolute
			 absolute-indexed-x))
   (ROR 106 (accumulator
			 zero-page
			 zero-page-indexed-x
			 absolute
			 absolute-indexed-x))
   ;; Transfer
   (TAX 170 (implied))
   (TAY 168 (implied))
   (TXA 138 (implied))
   (TYA 152 (implied))
   ;; Stack
   (TSX 186 (implied))
   (TXS 154 (implied))
   (PHA  72 (implied))
   (PHP   8 (implied))
   (PLA 104 (implied))
   (PLP  40 (implied))
   ;; Subroutine
   (JSR  32 (implied))
   (RTI  64 (implied))
   (RTS  96 (implied))
   ;; Set & Reset
   (CLC  24 (implied))
   (CLD 216 (implied))
   (CLI  88 (implied))
   (CLV 184 (implied))
   (SEC  56 (implied))
   (SED 248 (implied))
   (SEI 120 (implied))
   ;; Other
   (NOP 234 (implied))
   (BRK   0 (implied))))

;; Generated list of opcodes.
(defparameter
 *opcodes*
 (extract-keys *instructions*))