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Diffstat (limited to 'bas.h')
| -rw-r--r-- | bas.h | 142 |
1 files changed, 142 insertions, 0 deletions
@@ -0,0 +1,142 @@ +/* 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_ON 0x1e +#define CMD_GOSUB 0x0c +#define CMD_TRAP 0x0d +#define CMD_IF 0x07 +#define CMD_LIST 0x04 +#define CMD_RESTORE 0x23 +#define CMD_REM 0x00 +#define CMD_DATA 0x01 +#define CMD_ERROR 0x37 +#define CMD_FOR 0x08 +#define CMD_NEXT 0x09 +#define CMD_LET 0x06 +#define CMD_ILET 0x36 +#define CMD_DIM 0x14 +#define CMD_READ 0x22 +#define CMD_INPUT 0x02 +#define CMD_GET 0x29 +#define CMD_LOCATE 0x31 +#define CMD_NOTE 0x1b +#define OP_GOTO 0x17 +#define OP_GOSUB 0x18 +#define OP_THEN 0x1b +#define OP_COMMA 0x12 +#define OP_ARR_COMMA 0x3c +#define OP_SEMICOLON 0x15 +#define OP_EOS 0x14 +#define OP_EOL 0x16 +#define OP_NUMCONST 0x0e +#define OP_STRCONST 0x0f +#define OP_HASH 0x1c + +/* variable types, bits 6-7 of byte 0 of each vvtable entry. */ +#define TYPE_SCALAR 0 +#define TYPE_ARRAY 1 +#define TYPE_STRING 2 + +/* callbacks */ +#define CALLBACK(x) void x(unsigned int lineno, unsigned int pos, unsigned int tok, unsigned int end) +#define CALLBACK_PTR(x) void (*x)(unsigned int lineno, unsigned int pos, unsigned int tok, unsigned int end) +#define walk_all_code() walk_code(0, 32768) + +void walk_code(unsigned int startlineno, unsigned int endlineno); +unsigned char get_vartype(unsigned char tok); + +extern CALLBACK_PTR(on_start_line); +extern CALLBACK_PTR(on_bad_line_length); +extern CALLBACK_PTR(on_end_line); +extern CALLBACK_PTR(on_start_stmt); +extern CALLBACK_PTR(on_end_stmt); +extern CALLBACK_PTR(on_cmd_token); +extern CALLBACK_PTR(on_text); +extern CALLBACK_PTR(on_exp_token); +extern CALLBACK_PTR(on_var_token); +extern CALLBACK_PTR(on_string_const); +extern CALLBACK_PTR(on_num_const); +extern CALLBACK_PTR(on_trailing_garbage); + +/* 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); |