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/* bas.c - API for writing standalone programs that deal with
tokenized Atari 8-bit BASIC program. */
#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include <time.h>
#include "bas.h"
int verbose = 0;
unsigned short lomem;
unsigned short vntp;
unsigned short vntd;
unsigned short vvtp;
unsigned short stmtab;
unsigned short stmcur;
unsigned short starp;
unsigned short codestart;
unsigned short code_end;
unsigned short vnstart;
unsigned short vvstart;
int filelen;
const char *self;
unsigned char program[BUFSIZE];
FILE *input_file;
FILE *output_file;
void die(const char *msg) {
fprintf(stderr, "%s: %s\n", self, msg);
exit(1);
}
/* read entire file into memory */
int readfile(void) {
int got = fread(program, 1, BUFSIZE - 1, input_file);
if(verbose) fprintf(stderr, "Read %d bytes.\n", got);
if(!feof(input_file))
fprintf(stderr, "Warning: file is >64KB, way too big for a BASIC program.\n");
else if(got > MAX_PROG_SIZE)
fprintf(stderr, "Warning: file is %d bytes, suspiciously large for a BASIC program.\n", got);
fclose(input_file);
if(got < MIN_PROG_SIZE)
die("File too short to be a BASIC program (truncated?)\n");
return got;
}
/* get a 16-bit value from the file, in 6502 LSB/MSB order. */
unsigned short getword(int addr) {
return program[addr] | (program[addr + 1] << 8);
}
void setword(int addr, int value) {
program[addr] = value & 0xff;
program[addr + 1] = value >> 8;
}
void dump_header_vars(void) {
fprintf(stderr, "LOMEM $%04x VNTP $%04x VNTD $%04x VVTP $%04x\n", lomem, vntp, vntd, vvtp);
fprintf(stderr, "STMTAB $%04x STMCUR $%04x STARP $%04x\n", stmtab, stmcur, starp);
fprintf(stderr, "vnstart $%04x, vvstart $%04x, codestart $%04x, code_end $%04x\n", vnstart, vvstart, codestart, code_end);
}
void parse_header(void) {
lomem = getword(0);
vntp = getword(2);
vntd = getword(4);
vvtp = getword(6);
stmtab = getword(8);
stmcur = getword(10);
starp = getword(12);
codestart = stmtab - TBL_OFFSET - (vntp - 256);
vnstart = vntp - TBL_OFFSET;
vvstart = vvtp - TBL_OFFSET;
code_end = starp - TBL_OFFSET;
if(filelen < code_end) {
fprintf(stderr, "Warning: file is truncated: %d bytes, should be %d.\n", filelen, code_end);
}
if(verbose) dump_header_vars();
}
void update_header(void) {
setword(0, lomem);
setword(2, vntp);
setword(4, vntd);
setword(6, vvtp);
setword(8, stmtab);
setword(10, stmcur);
setword(12, starp);
}
/* sometimes the variable name table isn't large enough to hold
the generated variable names. move_code() makes more space,
by moving the rest of the program (including the variable value
table) up in memory. */
void move_code(int offset) {
unsigned char *dest = program + vvstart + offset;
if(dest < program || ((filelen + offset) > (BUFSIZE - 1))) {
die("Attempt to move memory out of range; corrupt header bytes?\n");
}
memmove(dest, program + vvstart, filelen);
vntd += offset;
vvtp += offset;
stmtab += offset;
stmcur += offset;
starp += offset;
update_header();
parse_header();
filelen += offset;
}
void adjust_vntable_size(int oldsize, int newsize) {
int move_by;
if(oldsize != newsize) {
move_by = newsize - oldsize;
if(verbose) fprintf(stderr,
"Need %d bytes for vntable, have %d, moving VVTP by %d to $%04x.\n",
newsize, oldsize, move_by, vvtp + move_by);
move_code(move_by);
}
}
void invalid_args(const char *arg) {
fprintf(stderr, "%s: Invalid argument '%s'.\n\n", self, arg);
exit(1);
}
FILE *open_file(const char *name, const char *mode) {
FILE *fp;
if(!(fp = fopen(name, mode))) {
perror(name);
exit(1);
}
return fp;
}
void open_input(const char *name) {
if(!name) {
if(isatty(fileno(stdin))) {
die("Can't read binary data from the terminal.");
}
if(freopen(NULL, "rb", stdin)) {
input_file = stdin;
return;
} else {
perror("stdin");
exit(1);
}
}
input_file = open_file(name, "rb");
}
void open_output(const char *name) {
if(!name || (strcmp(name, "-") == 0)) {
if(isatty(fileno(stdout))) {
die("Refusing to write binary data to the terminal.");
}
if(freopen(NULL, "wb", stdout)) {
output_file = stdout;
return;
} else {
perror("stdout");
exit(1);
}
}
output_file = open_file(name, "wb");
}
extern void set_self(const char *argv0) {
char *p;
self = argv0;
p = strrchr(self, '/');
if(p) self = p + 1;
}
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