aboutsummaryrefslogtreecommitdiff
path: root/fenders.c
blob: 55ad709a8b42d14c5d445ef900eac827aaeb0409 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <errno.h>
#include <string.h>
#include <ctype.h>

#include "fenders_bin.h"
#include "fenders_offsets.h"
#include "fendersdbl_bin.h"
#include "fendersdbl_offsets.h"

extern char *optarg;
extern int optind, opterr, optopt;

#ifndef VERSION
#define VERSION "???"
#endif

#define SELF "fenders"
#define BANNER SELF " v" VERSION " by B. Watson (WTFPL)\n"
#define DEFAULT_TITLE "atari arcade"
#define OPTIONS "hrscit:v"

char *usage =
	BANNER
	"Install Fenders 3-sector loader in boot sectors of an ATR image\n"
	"Usage: " SELF " -[hrcsiv] [-t title] infile.atr [outfile.atr]\n"
	"  -h         Print this help message\n"
	"  -r         DON'T reboot (coldstart) the Atari if Reset is pressed\n"
	"  -c         Rotate colors during load\n"
   "  -s         Screen off after load\n"
	"  -i         In-place update (original renamed to end in ~)\n"
	"  -v         Set inverse video bit in title (blue/red text)\n"
	"  -t title   Set title (up to 20 chars, default: '" DEFAULT_TITLE "')\n";

typedef enum { SD, DD } density;

void set_title(char *title, density dens, int inverse) {
	int i;
	int offset;
	unsigned char *bin;
	int len = strlen(title);

	if(dens == SD) {
		offset = OFFSET_TITLE;
		bin = fenders_bin;
	} else {
		offset = OFFSET_TITLE_DD;
		bin = fendersdbl_bin;
	}

	/* zero out the title area first (zeroes are Atari spaces BTW) */
	memset(&bin[offset], 0, 20);

	if(len > 20) {
		len = 20;
		fprintf(stderr, SELF ": Truncating title to 20 characters\n");
	} else if(!len) {
		return;
	}

	/* convert ASCII to Atari screen codes (not the same as ATASCII)
		charset in GR.2 is space plus:
		!"#$%'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_

		Punctuation comes out orange (blue with -v)
		Digits and uppercase letters are orange/blue
		Lowercase letters are green/red
		` = green/red @
		{ = green/red [
		| = green/red ^
		} = green/red ]
		~ = green/red ^
	 */
	for(i=0; i<len; i++) {
		char c = title[i];

		if(c >= 32 && c <= 95)
			c -= 32;

		if(inverse)
			c |= 128;

		title[i] = c;
	}

	/* Center title in 20-byte title area */
	memcpy(&bin[offset + 10 - len / 2], title, len);

	/*
	fprintf(stderr, SELF ": Set title to \"");
	for(i=0; i<20; i++) {
		char c = bin[offset + i];
		if(!c) c = ' ';
		if(!isprint(c)) c = '.';
		putc(c, stderr);
	}

	putc('"', stderr);
	putc('\n', stderr);
	*/
}

/* for set_coldstart(), set_rot_color(), set_screen_off(),
	see fenders.dasm (and fendersdbl.dasm) to understand what's going on.
	Search for the OFFSET_* strings. */

void set_coldstart(density dens) {
	if(dens == SD) {
		fenders_bin[OFFSET_COLDST_1] = 1;    /* operand for LDY # (replaces 0) */
		fenders_bin[OFFSET_COLDST_2] = 0xea; /* NOP (replaces INY) */
	} else {
		fendersdbl_bin[OFFSET_COLDST_1_DD] = 1;
		fendersdbl_bin[OFFSET_COLDST_2_DD] = 0xea;
	}
}

void set_rot_color(density dens) {
	if(dens == SD)
		fenders_bin[OFFSET_ROTCOLOR] = 0x8d; /* STA abs (replace LDA abs) */
	else
		fendersdbl_bin[OFFSET_ROTCOLOR_DD] = 0x8d;
}

void set_screen_off(density dens) {
	if(dens == SD)
		fenders_bin[OFFSET_SCREENOFF] = 0x8d; /* STA abs (replace LDA abs) */
	else
		fendersdbl_bin[OFFSET_SCREENOFF_DD] = 0x8d;
}

int main(int argc, char **argv) {
	int coldstart = 1, rot_color = 0, screen_off = 0;
	int c, res, size, inverse = 0;
	char title[21];
	int in_place = 0;
	char rename_to[4096];
	unsigned char buf[384], *bin;
	char *infile = "-", *outfile = "-";
	FILE *in = stdin, *out = stdout;
	density dens;

	/* initialize title (may be changed by -t option) */
	strcpy(title, DEFAULT_TITLE);

	/* parse options */
	while( (c = getopt(argc, argv, OPTIONS)) != -1) {
		switch(c) {
			case 'h':
				printf(usage);
				exit(0);
				break;

			case 'r':
				coldstart = 0;
				break;

			case 'c':
				rot_color = 1;
				break;

			case 's':
				screen_off = 1;
				break;

			case 't':
				strcpy(title, optarg);
				break;

			case 'i':
				in_place = 1;
				break;

			case 'v':
				inverse = 1;
				break;

			default:
				fprintf(stderr, usage);
				exit(1);
				break;
		}
	}

	/* get input filename if present */
	if(optind < argc)
		infile = argv[optind++];

	/* get output filename if present */
	if(!in_place && optind < argc)
		outfile = argv[optind++];

	if(optind < argc) {
		fprintf(stderr, SELF
				": Ignoring extra junk '%s ...' on command line.\n",
				argv[optind]);
	}

	if(in_place) {
		/* rename infile to infile~, set outfile to old infile */
		int len = strlen(infile);

		if(strcmp(infile, "-") == 0) {
			fprintf(stderr, SELF
					": Can't use in-place mode with standard input.\n");
			exit(1);
		}

		strcpy(rename_to, infile);
		rename_to[len] = '~';
		rename_to[len + 1] = '\0';

		fprintf(stderr, SELF ": Backing up %s to %s\n", infile, rename_to);
		if(link(infile, rename_to)) {
			perror("link()");
			exit(1);
		}

		if(unlink(infile)) {
			perror("unlink()");
			exit(1);
		}

		outfile = infile;
		infile = rename_to;
	}

	/* open input and output files, if not stdin/stdout */
	if(strcmp(infile, "-") != 0) {
		in = fopen(infile, "rb");
		if(!in) {
			perror(infile);
			exit(1);
		}
	}

	/* read ATR header */
	res = fread(buf, 1, 16, in);
	if(res < 16) {
		perror(infile);
		exit(1);
	}

	/* make sure it's an ATR image */
	if( !(buf[0] == 0x96 && buf[1] == 0x02) ) {
		fprintf(stderr, SELF
				": %s not an ATR file (no NICKATARI signature)!\n"
				"If this is an XFD file, try xfd2atr\n",
				infile);
		exit(2);
	}

	/* get sector size. The single- and double-density versions of
		the loader are totally different, so pick the one we need. */
	if( (buf[4] == 0x80 && buf[5] == 0x00) ) {
		dens = SD;
		bin = fenders_bin;
	} else if( (buf[4] == 0x00 && buf[5] == 0x01) ) {
		dens = DD;
		bin = fendersdbl_bin;
	} else {
		fprintf(stderr, SELF ": ATR image must have 128 or 256 byte sectors\n");
		exit(2);
	}

	/* modify the loader according to the user's options */
	set_title(title, dens, inverse);
	if(coldstart) set_coldstart(dens);
	if(rot_color) set_rot_color(dens);
	if(screen_off) set_screen_off(dens);

	/* size of ATR image in bytes (minus the header). We don't support
		DD images less than 720 sectors. */
	size = (buf[2] + (buf[3] << 8) + (buf[6] << 16)) * 16;
	if(dens == SD && size < (128 * 369)) {
		fprintf(stderr, SELF
				": ATR is single density < 369 sectors, not supported\n"
				"Use atrsize to grow the image.\n");
		exit(2);
	} else if(dens == SD && size > (128 * 720)) {
		fprintf(stderr, SELF
				": ATR is single density > 720 sectors; "
				"some files may not appear in menu.\n");
	} else if(dens == DD && size < (128 * 3 + 256 * 717)) {
		fprintf(stderr, SELF
				": ATR is double density < 720 sectors, not supported\n"
				"Use atrsize to grow the image.\n");
		exit(2);
	} else if(dens == DD && size > (128 * 3 + 256 * 717)) {
		/* 20071005 bkw: whoops, we were truncating large images to 180K.
			The bootloader doesn't work with MyDOS >180K formats anyway, so
			don't try.
		fprintf(stderr, SELF
				": ATR file is double density > 720 sectors; some files may not"
				"appear in the menu or load correctly\n");
				*/

		/* Abort instead */
		fprintf(stderr, SELF
				": ATR is double density > 720 sectors, not supported "
				"by bootloader (try MyPicoDOS)\n");
		exit(2);
	}

	/* Input looks OK, open the output... */
	if(strcmp(outfile, "-") != 0) {
		out = fopen(outfile, "wb");
		if(!out) {
			fclose(in);
			perror(outfile);
			exit(1);
		}
	} else if(isatty(fileno(stdout))) {
		/* don't scare the n00bs! */
		fprintf(stderr,
				SELF ": Standard output is a terminal, not writing binary data.\n"
				"Either redirect to a file or set the output filename.\n");
		exit(1);
	}

	/* write ATR header */
	res = fwrite(buf, 1, 16, out);
	if(res < 16) {
		perror(outfile);
		exit(1);
	}

	/* read (and ignore) first 3 sectors. A DD image still uses SD
		sectors for the first 3 (boot) sectors on the disk. */
	res = fread(buf, 1, 384, in);
	if(res < 384) {
		perror(infile);
		exit(1);
	}

	/* Write the loader. For SD disks, this is the whole thing.
		For DD disks, this is the first 384 bytes (3 boot sectors),
		and we'll have to write the rest of the object code to sector 720 */
	res = fwrite(bin, 1, 384, out);
	if(res < 384) {
		perror(outfile);
		exit(1);
	}

	if(dens == SD) {
		/* single density can just use a simple copy loop */
		while( (c = getc(in)) != EOF )
			putc(c, out);
	} else {
		/* double density: copy sectors 4-719 as-is... */
		for(c=4; c<720; c++) {
			if(fread(buf, 1, 256, in) < 256) {
				if(feof(in)) {
					fprintf(stderr, SELF
							": got premature EOF (bad/truncated ATR image).\n");
				} else {
					perror(infile);
				}
				exit(1);
			}

			if(fwrite(buf, 1, 256, out) < 256) {
				perror(outfile);
				exit(1);
			}
		}

		/* TODO: check the VTOC and/or look for non-zero data in sector
			720, warn the user if the sector was in use. */

		/* TODO: fix bootloader to work with MyDOS-style sector link bytes.
			Also, store last part of bootloader somewhere not used by MyDOS,
			maybe sector 369 (last directory sector, unused on disks with
			less than 56 files... and 56 files is way too many to fit on
			screen in GR.1). This should happen on both single and double
			density images. */

		/* TODO: examine directory sectors, look for:
			- DOS 2.5 extended files. Either warn about them, or clear the
			extended flag (which causes the bootloader to load them just fine).
			- MyDOS subdirectories. It's probably best to abort in that case.
			- Non-DOS-compatible disk formats (boot disks, SpartaDOS, Atari
			DOS 3 or 4).
		*/

		/* TODO: add option to delete DOS.SYS and DUP.SYS (or more likely,
			delete them by default, and add option to allow user to keep them).
		*/

		/* TODO: option that creates a new, blank image, with bootloader
			already on it? There's already "atrsize -b" for creating a blank
			image... */

		/* write the rest of the loader code code to sector 720.
		 	The code in the boot sectors will load sector 720. */
		if(fwrite(bin+384, 1, 256, out) < 256) {
			perror(outfile);
			exit(1);
		}
	}

	/* set return value: 0 for success, 1 for failure */
	c = 0;

	if(ferror(in)) {
		perror(infile);
		c = 1;
	}

	if(ferror(out)) {
		perror(outfile);
		c = 1;
	}

	/* ...and I'm spent! */
	return c;
}