/*
* Copyright (c) 2007 Jeremy English <jhe@jeremyenglish.org>
*
* Permission to use, copy, modify, distribute, and sell this software and its
* documentation for any purpose is hereby granted without fee, provided that
* the above copyright notice appear in all copies and that both that
* copyright notice and this permission notice appear in supporting
* documentation. No representations are made about the suitability of this
* software for any purpose. It is provided "as is" without express or
* implied warranty.
*
* Created: 07-May-2007
*/
/*
This is a port of the javascript 6502 assembler, compiler and
debugger. The orignal code was copyright 2006 by Stian Soreng -
www.6502asm.com
The stack space is in page $100 to $1ff. The video buffer starts at
$200 and is 1024 bytes. Programs get loaded at address
$600. Address $fe is random and byte $ff is used for user input.
User input is disabled.
*/
#ifndef __ASM6502_H__
#define __ASM6502_H__
typedef uint8_t Bit8;
typedef uint16_t Bit16;
typedef uint32_t Bit32;
#undef BOOL
#undef TRUE
#undef FALSE
#define BOOL Bit8
#define TRUE 1
#define FALSE 0
enum {
MAX_LABEL_LEN = 80,
NUM_OPCODES = 56, /* Number of unique instructions not counting DCB */
MEM_64K = 65536, /* We have 64k of memory to work with. */
MAX_PARAM_VALUE = 25, /* The number of values allowed behind dcb */
MAX_CMD_LEN = 4, /* Each assembly command is 3 characeters long */
/* The stack works from the top down in page $100 to $1ff */
STACK_TOP = 0x1ff,
STACK_BOTTOM = 0x100,
PROG_START = 0x600 /* The default entry point for the program */
};
typedef enum{
SINGLE, IMMEDIATE_VALUE, IMMEDIATE_GREAT,
IMMEDIATE_LESS, INDIRECT_X, INDIRECT_Y,
ZERO, ZERO_X, ZERO_Y,
ABS_VALUE, ABS_OR_BRANCH, ABS_X, ABS_Y,
ABS_LABEL_X, ABS_LABEL_Y, DCB_PARAM
} m6502_AddrMode;
typedef struct machine_6502 machine_6502;
typedef struct {
char name[MAX_CMD_LEN];
Bit8 Imm;
Bit8 ZP;
Bit8 ZPX;
Bit8 ZPY;
Bit8 ABS;
Bit8 ABSX;
Bit8 ABSY;
Bit8 INDX;
Bit8 INDY;
Bit8 SNGL;
Bit8 BRA;
void (*func) (machine_6502*, m6502_AddrMode);
} m6502_Opcodes;
/* Used to cache the index of each opcode */
typedef struct {
Bit8 index;
m6502_AddrMode adm;
} m6502_OpcodeIndex;
/* Plotter is a function that will be called everytime a pixel
needs to be updated. The first two parameter are the x and y
values. The third parameter is the color index:
Color Index Table
00 black #000000
01 white #ffffff
02 Red #880000
03 seafoam #aaffee
04 fuscia #cc44cc
05 green #00cc55
06 blue #0000aa
07 Yellow #eeee77
08 tangerine #dd8855
09 brown #664400
10 salmon #ff7777
11 charcoal #333333
12 smoke #777777
13 lime #aaff66
14 light blue #0088ff
15 gray #bbbbbb
The plotter state variable of the machine gets passed as the forth
parameter. You can use this parameter to store state information.
*/
typedef void (*m6502_Plotter) (Bit8, Bit8, Bit8, void*);
struct machine_6502 {
BOOL codeCompiledOK;
Bit8 regA;
Bit8 regX;
Bit8 regY;
Bit8 regP;
Bit16 regPC; /* A pair of 8 bit registers */
Bit16 regSP;
Bit16 defaultCodePC;
Bit8 memory[MEM_64K];
BOOL runForever;
int labelPtr;
BOOL codeRunning;
int myInterval;
m6502_Opcodes opcodes[NUM_OPCODES];
int screen[32][32];
int codeLen;
m6502_OpcodeIndex opcache[0xff];
m6502_Plotter plot;
void *plotterState;
};
/* build6502() - Creates an instance of the 6502 machine */
machine_6502 *m6502_build(void);
/* destroy6502() - compile the file and exectue it until the program
is finished */
void m6502_destroy6502(machine_6502 *machine);
/* eval_file() - Compiles and runs a file until the program is
finished */
void m6502_eval_file(machine_6502 *machine, const char *filename,
m6502_Plotter plot, void *plotterState);
/* start_eval_file() - Compile the file and execute the first
instruction */
void m6502_start_eval_file(machine_6502 *machine, const char *filename,
m6502_Plotter plot, void *plotterState);
/* XXX
void m6502_start_eval_binary(machine_6502 *machine, Bit8 *program,
unsigned int proglen,
Plotter plot, void *plotterState);
*/
void m6502_start_eval_string(machine_6502 *machine, const char *code,
m6502_Plotter plot, void *plotterState);
/* next_eval() - Execute the next insno of machine instructions */
void m6502_next_eval(machine_6502 *machine, int insno);
/* hexDump() - Dumps memory to output */
void m6502_hexDump(machine_6502 *machine, Bit16 start,
Bit16 numbytes, FILE *output);
/* Disassemble() - Prints the assembly code for the program currently
loaded in memory.*/
void m6502_disassemble(machine_6502 *machine, FILE *output);
/* trace() - Prints to output the current value of registers, the
current nmemonic, memory address and value. */
void m6502_trace(machine_6502 *machine, FILE *output);
/* save_program() - Writes a binary file of the program loaded in
memory. */
/* XXX
void save_program(machine_6502 *machine, const char *filename);
*/
#endif /* __ASM6502_H__ */
