/* bas.h - API for writing standalone programs that deal with
	tokenized Atari 8-bit BASIC program. */

/* maximum size of the program in memory. 64KB is actually way overkill. */
#define BUFSIZE 65536

/* the difference between the VVTP and VNTP values in the file, and the
	actual file positions of the variable names and values. */
#define TBL_OFFSET 0xf2

/* minimum program size, for a program that has no variables and
	only one line of code (the immediate line 32768, consisting only of
	one token, which would be CSAVE). anything smaller than this, we
	can't process. */
#define MIN_PROG_SIZE 21

/* maximum practical size for a BASIC program. if a file exceeds this
	size, we warn about it, but otherwise process it normally.
	this value is derived by subtracting the default LOMEM without DOS
	($0700) from the start of the display list in GR.0 ($9c20, on a 48K Atari).
 */
#define MAX_PROG_SIZE 38176

/* maximum number of variables in the variable name and value tables. this
	could be 128, but "ERROR- 4" still expands the tables. Entries >128
	don't have tokens, can't be referred to in code, but we'll preserve
	them anyway. */
#define MAXVARS 256

/* tokenized colon (statement separator) */
#define TOK_COLON 0x14

/* BASIC tokens. Not a full set. BASIC uses 2 sets of tokens, one
   for commands and the other for operators (which is to say, everything
   *not* a command). */
#define CMD_GOTO    0x0a
#define CMD_GO_TO   0x0b
#define CMD_GOSUB   0x0c
#define CMD_TRAP    0x0d
#define CMD_LIST    0x04
#define CMD_RESTORE 0x23
#define CMD_REM     0x00
#define CMD_DATA    0x01
#define CMD_ERROR   0x37
#define OP_GOTO     0x17
#define OP_GOSUB    0x18
#define OP_THEN     0x1b
#define OP_COMMA    0x12
#define OP_EOS      0x14
#define OP_EOL      0x16
#define OP_NUMCONST 0x0e
#define OP_STRCONST 0x0f

/* variable types, bits 6-7 of byte 0 of each vvtable entry. */
#define TYPE_SCALAR 0
#define TYPE_ARRAY  1
#define TYPE_STRING 2

/* BASIC 14-byte header values */
extern unsigned short lomem;
extern unsigned short vntp;
extern unsigned short vntd;
extern unsigned short vvtp;
extern unsigned short stmtab;
extern unsigned short stmcur;
extern unsigned short starp;

/* positions where various parts of the file start,
	derived from the header vars above. */
extern unsigned short codestart;
extern unsigned short code_end;
extern unsigned short vnstart;
extern unsigned short vvstart;
extern int filelen;

/* name of executable, taken from argv[0] */
extern const char *self;

/* entire file gets read into memory (for now) */
extern unsigned char program[BUFSIZE];

/* file handles */
extern FILE *input_file;
extern FILE *output_file;

extern char *output_filename;

extern int verbose;

extern void set_self(const char *argv0);
extern void die(const char *msg);
extern void parse_general_args(int argc, char **argv, void (*helpfunc)());
extern int writefile(void);
extern void readfile(void);
extern unsigned short getword(int addr);
extern void setword(int addr, int value);
extern void dump_header_vars(void);
extern void parse_header(void);
extern void update_header(void);
extern void move_code(int offset);
extern void adjust_vntable_size(int oldsize, int newsize);
extern int vntable_ok(void);
extern void invalid_args(const char *arg);
extern FILE *open_file(const char *name, const char *mode);
extern void open_input(const char *name);
extern void open_output(const char *name);