1 /*-
2 * Copyright (c) 2008-2009 TAKAHASHI Yoshihiro
3 * Copyright (c) 1998 Robert Nordier
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms are freely
7 * permitted provided that the above copyright notice and this
8 * paragraph and the following disclaimer are duplicated in all
9 * such forms.
10 *
11 * This software is provided "AS IS" and without any express or
12 * implied warranties, including, without limitation, the implied
13 * warranties of merchantability and fitness for a particular
14 * purpose.
15 */
16
17 #include <sys/cdefs.h>
18 __FBSDID("$FreeBSD: stable/10/sys/boot/pc98/boot2/boot2.c 295453 2016-02-09 22:32:24Z emaste $");
19
20 #include <sys/param.h>
21 #include <sys/disklabel.h>
22 #include <sys/diskpc98.h>
23 #include <sys/dirent.h>
24 #include <sys/reboot.h>
25
26 #include <machine/bootinfo.h>
27 #include <machine/cpufunc.h>
28 #include <machine/elf.h>
29
30 #include <stdarg.h>
31
32 #include <a.out.h>
33
34 #include <btxv86.h>
35
36 #include "boot2.h"
37 #include "lib.h"
38 #include "paths.h"
39 #include "rbx.h"
40
41 /* Define to 0 to omit serial support */
42 #ifndef SERIAL
43 #define SERIAL 0
44 #endif
45
46 #define IO_KEYBOARD 1
47 #define IO_SERIAL 2
48
49 #if SERIAL
50 #define DO_KBD (ioctrl & IO_KEYBOARD)
51 #define DO_SIO (ioctrl & IO_SERIAL)
52 #else
53 #define DO_KBD (1)
54 #define DO_SIO (0)
55 #endif
56
57 #define SECOND 1 /* Circa that many ticks in a second. */
58
59 #define ARGS 0x900
60 #define NOPT 14
61 #define NDEV 3
62
63 #define DRV_DISK 0xf0
64 #define DRV_UNIT 0x0f
65
66 #define TYPE_AD 0
67 #define TYPE_DA 1
68 #define TYPE_FD 2
69
70 extern uint32_t _end;
71
72 static const char optstr[NOPT] = "DhaCcdgmnpqrsv"; /* Also 'P', 'S' */
73 static const unsigned char flags[NOPT] = {
74 RBX_DUAL,
75 RBX_SERIAL,
76 RBX_ASKNAME,
77 RBX_CDROM,
78 RBX_CONFIG,
79 RBX_KDB,
80 RBX_GDB,
81 RBX_MUTE,
82 RBX_NOINTR,
83 RBX_PAUSE,
84 RBX_QUIET,
85 RBX_DFLTROOT,
86 RBX_SINGLE,
87 RBX_VERBOSE
88 };
89
90 static const char *const dev_nm[NDEV] = {"ad", "da", "fd"};
91 static const unsigned char dev_maj[NDEV] = {30, 4, 2};
92 static const unsigned char dev_daua[NDEV] = {0x80, 0xa0, 0x90};
93
94 static struct dsk {
95 unsigned daua;
96 unsigned type;
97 unsigned disk;
98 unsigned unit;
99 unsigned head;
100 unsigned sec;
101 uint8_t slice;
102 uint8_t part;
103 unsigned start;
104 } dsk;
105 static char cmd[512], cmddup[512], knamebuf[1024];
106 static const char *kname;
107 uint32_t opts;
108 static struct bootinfo bootinfo;
109 #if SERIAL
110 static int comspeed = SIOSPD;
111 static uint8_t ioctrl = IO_KEYBOARD;
112 #endif
113
114 void exit(int);
115 static void load(void);
116 static int parse(void);
117 static int dskread(void *, unsigned, unsigned);
118 static void printf(const char *,...);
119 static void putchar(int);
120 static int drvread(void *, unsigned);
121 static int keyhit(unsigned);
122 static int xputc(int);
123 static int xgetc(int);
124 static inline int getc(int);
125
126 static void memcpy(void *, const void *, int);
127 static void
memcpy(void * dst,const void * src,int len)128 memcpy(void *dst, const void *src, int len)
129 {
130 const char *s = src;
131 char *d = dst;
132
133 while (len--)
134 *d++ = *s++;
135 }
136
137 static inline int
strcmp(const char * s1,const char * s2)138 strcmp(const char *s1, const char *s2)
139 {
140 for (; *s1 == *s2 && *s1; s1++, s2++);
141 return (unsigned char)*s1 - (unsigned char)*s2;
142 }
143
144 #define UFS_SMALL_CGBASE
145 #include "ufsread.c"
146
147 static inline int
xfsread(ufs_ino_t inode,void * buf,size_t nbyte)148 xfsread(ufs_ino_t inode, void *buf, size_t nbyte)
149 {
150 if ((size_t)fsread(inode, buf, nbyte) != nbyte) {
151 printf("Invalid %s\n", "format");
152 return -1;
153 }
154 return 0;
155 }
156
157 static inline void
getstr(void)158 getstr(void)
159 {
160 char *s;
161 int c;
162
163 s = cmd;
164 for (;;) {
165 switch (c = xgetc(0)) {
166 case 0:
167 break;
168 case '\177':
169 case '\b':
170 if (s > cmd) {
171 s--;
172 printf("\b \b");
173 }
174 break;
175 case '\n':
176 case '\r':
177 *s = 0;
178 return;
179 default:
180 if (s - cmd < sizeof(cmd) - 1)
181 *s++ = c;
182 putchar(c);
183 }
184 }
185 }
186
187 static inline void
putc(int c)188 putc(int c)
189 {
190
191 v86.ctl = V86_ADDR | V86_CALLF | V86_FLAGS;
192 v86.addr = PUTCORG; /* call to putc in boot1 */
193 v86.eax = c;
194 v86int();
195 v86.ctl = V86_FLAGS;
196 }
197
198 static inline int
is_scsi_hd(void)199 is_scsi_hd(void)
200 {
201
202 if ((*(u_char *)PTOV(0x482) >> dsk.unit) & 0x01)
203 return 1;
204
205 return 0;
206 }
207
208 static inline void
fix_sector_size(void)209 fix_sector_size(void)
210 {
211 u_char *p;
212
213 p = (u_char *)PTOV(0x460 + dsk.unit * 4); /* SCSI equipment parameter */
214
215 if ((p[0] & 0x1f) == 7) { /* SCSI MO */
216 if (!(p[3] & 0x30)) { /* 256B / sector */
217 p[3] |= 0x10; /* forced set 512B / sector */
218 p[3 + 0xa1000] |= 0x10;
219 }
220 }
221 }
222
223 static inline uint32_t
get_diskinfo(void)224 get_diskinfo(void)
225 {
226
227 if (dsk.disk == 0x30) { /* 1440KB FD */
228 /* 80 cylinders, 2 heads, 18 sectors */
229 return (80 << 16) | (2 << 8) | 18;
230 } else if (dsk.disk == 0x90) { /* 1200KB FD */
231 /* 80 cylinders, 2 heads, 15 sectors */
232 return (80 << 16) | (2 << 8) | 15;
233 } else if (dsk.disk == 0x80 || is_scsi_hd()) { /* IDE or SCSI HDD */
234 v86.addr = 0x1b;
235 v86.eax = 0x8400 | dsk.daua;
236 v86int();
237 return (v86.ecx << 16) | v86.edx;
238 }
239
240 /* SCSI MO or CD */
241 fix_sector_size(); /* SCSI MO */
242
243 /* other SCSI devices */
244 return (65535 << 16) | (8 << 8) | 32;
245 }
246
247 static void
set_dsk(void)248 set_dsk(void)
249 {
250 uint32_t di;
251
252 di = get_diskinfo();
253
254 dsk.head = (di >> 8) & 0xff;
255 dsk.sec = di & 0xff;
256 dsk.start = 0;
257 }
258
259 #ifdef GET_BIOSGEOM
260 static uint32_t
bd_getbigeom(int bunit)261 bd_getbigeom(int bunit)
262 {
263 int hds = 0;
264 int unit = 0x80; /* IDE HDD */
265 u_int addr = 0x55d;
266
267 while (unit < 0xa7) {
268 if (*(u_char *)PTOV(addr) & (1 << (unit & 0x0f)))
269 if (hds++ == bunit)
270 break;
271
272 if (unit >= 0xA0) {
273 int media = ((unsigned *)PTOV(0x460))[unit & 0x0F] & 0x1F;
274
275 if (media == 7 && hds++ == bunit) /* SCSI MO */
276 return(0xFFFE0820); /* C:65535 H:8 S:32 */
277 }
278 if (++unit == 0x84) {
279 unit = 0xA0; /* SCSI HDD */
280 addr = 0x482;
281 }
282 }
283 if (unit == 0xa7)
284 return 0x4F020F; /* 1200KB FD C:80 H:2 S:15 */
285 v86.addr = 0x1b;
286 v86.eax = 0x8400 | unit;
287 v86int();
288 if (V86_CY(v86.efl))
289 return 0x4F020F; /* 1200KB FD C:80 H:2 S:15 */
290 return ((v86.ecx & 0xffff) << 16) | (v86.edx & 0xffff);
291 }
292 #endif
293
294 static int
check_slice(void)295 check_slice(void)
296 {
297 struct pc98_partition *dp;
298 char *sec;
299 unsigned i, cyl;
300
301 sec = dmadat->secbuf;
302 cyl = *(uint16_t *)PTOV(ARGS);
303 set_dsk();
304
305 if (dsk.type == TYPE_FD)
306 return (WHOLE_DISK_SLICE);
307 if (drvread(sec, PC98_BBSECTOR))
308 return (WHOLE_DISK_SLICE); /* Read error */
309 dp = (void *)(sec + PC98_PARTOFF);
310 for (i = 0; i < PC98_NPARTS; i++) {
311 if (dp[i].dp_mid == DOSMID_386BSD) {
312 if (dp[i].dp_scyl <= cyl && cyl <= dp[i].dp_ecyl)
313 return (BASE_SLICE + i);
314 }
315 }
316
317 return (WHOLE_DISK_SLICE);
318 }
319
320 int
main(void)321 main(void)
322 {
323 #ifdef GET_BIOSGEOM
324 int i;
325 #endif
326 uint8_t autoboot;
327 ufs_ino_t ino;
328 size_t nbyte;
329
330 dmadat = (void *)(roundup2(__base + (int32_t)&_end, 0x10000) - __base);
331 v86.ctl = V86_FLAGS;
332 v86.efl = PSL_RESERVED_DEFAULT | PSL_I;
333 dsk.daua = *(uint8_t *)PTOV(0x584);
334 dsk.disk = dsk.daua & DRV_DISK;
335 dsk.unit = dsk.daua & DRV_UNIT;
336 if (dsk.disk == 0x80)
337 dsk.type = TYPE_AD;
338 else if (dsk.disk == 0xa0)
339 dsk.type = TYPE_DA;
340 else /* if (dsk.disk == 0x30 || dsk.disk == 0x90) */
341 dsk.type = TYPE_FD;
342 dsk.slice = check_slice();
343 #ifdef GET_BIOSGEOM
344 for (i = 0; i < N_BIOS_GEOM; i++)
345 bootinfo.bi_bios_geom[i] = bd_getbigeom(i);
346 #endif
347 bootinfo.bi_version = BOOTINFO_VERSION;
348 bootinfo.bi_size = sizeof(bootinfo);
349
350 /* Process configuration file */
351
352 autoboot = 1;
353
354 if ((ino = lookup(PATH_CONFIG)) ||
355 (ino = lookup(PATH_DOTCONFIG))) {
356 nbyte = fsread(ino, cmd, sizeof(cmd) - 1);
357 cmd[nbyte] = '\0';
358 }
359
360 if (*cmd) {
361 memcpy(cmddup, cmd, sizeof(cmd));
362 if (parse())
363 autoboot = 0;
364 if (!OPT_CHECK(RBX_QUIET))
365 printf("%s: %s", PATH_CONFIG, cmddup);
366 /* Do not process this command twice */
367 *cmd = 0;
368 }
369
370 /*
371 * Try to exec stage 3 boot loader. If interrupted by a keypress,
372 * or in case of failure, try to load a kernel directly instead.
373 */
374
375 if (!kname) {
376 kname = PATH_LOADER;
377 if (autoboot && !keyhit(3*SECOND)) {
378 load();
379 kname = PATH_KERNEL;
380 }
381 }
382
383 /* Present the user with the boot2 prompt. */
384
385 for (;;) {
386 if (!autoboot || !OPT_CHECK(RBX_QUIET))
387 printf("\nFreeBSD/pc98 boot\n"
388 "Default: %u:%s(%u,%c)%s\n"
389 "boot: ",
390 dsk.unit, dev_nm[dsk.type], dsk.unit,
391 'a' + dsk.part, kname);
392 if (DO_SIO)
393 sio_flush();
394 if (!autoboot || keyhit(3*SECOND))
395 getstr();
396 else if (!autoboot || !OPT_CHECK(RBX_QUIET))
397 putchar('\n');
398 autoboot = 0;
399 if (parse())
400 putchar('\a');
401 else
402 load();
403 }
404 }
405
406 /* XXX - Needed for btxld to link the boot2 binary; do not remove. */
407 void
exit(int x)408 exit(int x)
409 {
410 }
411
412 static void
load(void)413 load(void)
414 {
415 union {
416 struct exec ex;
417 Elf32_Ehdr eh;
418 } hdr;
419 static Elf32_Phdr ep[2];
420 static Elf32_Shdr es[2];
421 caddr_t p;
422 ufs_ino_t ino;
423 uint32_t addr;
424 int i, j;
425
426 if (!(ino = lookup(kname))) {
427 if (!ls)
428 printf("No %s\n", kname);
429 return;
430 }
431 if (xfsread(ino, &hdr, sizeof(hdr)))
432 return;
433
434 if (N_GETMAGIC(hdr.ex) == ZMAGIC) {
435 addr = hdr.ex.a_entry & 0xffffff;
436 p = PTOV(addr);
437 fs_off = PAGE_SIZE;
438 if (xfsread(ino, p, hdr.ex.a_text))
439 return;
440 p += roundup2(hdr.ex.a_text, PAGE_SIZE);
441 if (xfsread(ino, p, hdr.ex.a_data))
442 return;
443 } else if (IS_ELF(hdr.eh)) {
444 fs_off = hdr.eh.e_phoff;
445 for (j = i = 0; i < hdr.eh.e_phnum && j < 2; i++) {
446 if (xfsread(ino, ep + j, sizeof(ep[0])))
447 return;
448 if (ep[j].p_type == PT_LOAD)
449 j++;
450 }
451 for (i = 0; i < 2; i++) {
452 p = PTOV(ep[i].p_paddr & 0xffffff);
453 fs_off = ep[i].p_offset;
454 if (xfsread(ino, p, ep[i].p_filesz))
455 return;
456 }
457 p += roundup2(ep[1].p_memsz, PAGE_SIZE);
458 bootinfo.bi_symtab = VTOP(p);
459 if (hdr.eh.e_shnum == hdr.eh.e_shstrndx + 3) {
460 fs_off = hdr.eh.e_shoff + sizeof(es[0]) *
461 (hdr.eh.e_shstrndx + 1);
462 if (xfsread(ino, &es, sizeof(es)))
463 return;
464 for (i = 0; i < 2; i++) {
465 *(Elf32_Word *)p = es[i].sh_size;
466 p += sizeof(es[i].sh_size);
467 fs_off = es[i].sh_offset;
468 if (xfsread(ino, p, es[i].sh_size))
469 return;
470 p += es[i].sh_size;
471 }
472 }
473 addr = hdr.eh.e_entry & 0xffffff;
474 bootinfo.bi_esymtab = VTOP(p);
475 } else {
476 printf("Invalid %s\n", "format");
477 return;
478 }
479
480 bootinfo.bi_kernelname = VTOP(kname);
481 bootinfo.bi_bios_dev = dsk.daua;
482 __exec((caddr_t)addr, RB_BOOTINFO | (opts & RBX_MASK),
483 MAKEBOOTDEV(dev_maj[dsk.type], dsk.slice, dsk.unit, dsk.part),
484 0, 0, 0, VTOP(&bootinfo));
485 }
486
487 static int
parse()488 parse()
489 {
490 char *arg = cmd;
491 char *ep, *p, *q;
492 const char *cp;
493 unsigned int drv;
494 int c, i, j;
495
496 while ((c = *arg++)) {
497 if (c == ' ' || c == '\t' || c == '\n')
498 continue;
499 for (p = arg; *p && *p != '\n' && *p != ' ' && *p != '\t'; p++);
500 ep = p;
501 if (*p)
502 *p++ = 0;
503 if (c == '-') {
504 while ((c = *arg++)) {
505 if (c == 'P') {
506 if (*(uint8_t *)PTOV(0x481) & 0x48) {
507 cp = "yes";
508 } else {
509 opts |= OPT_SET(RBX_DUAL) | OPT_SET(RBX_SERIAL);
510 cp = "no";
511 }
512 printf("Keyboard: %s\n", cp);
513 continue;
514 #if SERIAL
515 } else if (c == 'S') {
516 j = 0;
517 while ((unsigned int)(i = *arg++ - '0') <= 9)
518 j = j * 10 + i;
519 if (j > 0 && i == -'0') {
520 comspeed = j;
521 break;
522 }
523 /* Fall through to error below ('S' not in optstr[]). */
524 #endif
525 }
526 for (i = 0; c != optstr[i]; i++)
527 if (i == NOPT - 1)
528 return -1;
529 opts ^= OPT_SET(flags[i]);
530 }
531 #if SERIAL
532 ioctrl = OPT_CHECK(RBX_DUAL) ? (IO_SERIAL|IO_KEYBOARD) :
533 OPT_CHECK(RBX_SERIAL) ? IO_SERIAL : IO_KEYBOARD;
534 if (DO_SIO) {
535 if (sio_init(115200 / comspeed) != 0)
536 ioctrl &= ~IO_SERIAL;
537 }
538 #endif
539 } else {
540 for (q = arg--; *q && *q != '('; q++);
541 if (*q) {
542 drv = -1;
543 if (arg[1] == ':') {
544 drv = *arg - '0';
545 if (drv > 9)
546 return (-1);
547 arg += 2;
548 }
549 if (q - arg != 2)
550 return -1;
551 for (i = 0; arg[0] != dev_nm[i][0] ||
552 arg[1] != dev_nm[i][1]; i++)
553 if (i == NDEV - 1)
554 return -1;
555 dsk.type = i;
556 arg += 3;
557 dsk.unit = *arg - '0';
558 if (arg[1] != ',' || dsk.unit > 9)
559 return -1;
560 arg += 2;
561 dsk.slice = WHOLE_DISK_SLICE;
562 if (arg[1] == ',') {
563 dsk.slice = *arg - '0' + 1;
564 if (dsk.slice > PC98_NPARTS + 1)
565 return -1;
566 arg += 2;
567 }
568 if (arg[1] != ')')
569 return -1;
570 dsk.part = *arg - 'a';
571 if (dsk.part > 7)
572 return (-1);
573 arg += 2;
574 if (drv == -1)
575 drv = dsk.unit;
576 dsk.disk = dev_daua[dsk.type];
577 dsk.daua = dsk.disk | dsk.unit;
578 dsk_meta = 0;
579 }
580 if ((i = ep - arg)) {
581 if ((size_t)i >= sizeof(knamebuf))
582 return -1;
583 memcpy(knamebuf, arg, i + 1);
584 kname = knamebuf;
585 }
586 }
587 arg = p;
588 }
589 return 0;
590 }
591
592 static int
dskread(void * buf,unsigned lba,unsigned nblk)593 dskread(void *buf, unsigned lba, unsigned nblk)
594 {
595 struct pc98_partition *dp;
596 struct disklabel *d;
597 char *sec;
598 unsigned i;
599 uint8_t sl;
600 u_char *p;
601
602 if (!dsk_meta) {
603 sec = dmadat->secbuf;
604 set_dsk();
605 if (dsk.type == TYPE_FD)
606 goto unsliced;
607 if (drvread(sec, PC98_BBSECTOR))
608 return -1;
609 dp = (void *)(sec + PC98_PARTOFF);
610 sl = dsk.slice;
611 if (sl < BASE_SLICE) {
612 for (i = 0; i < PC98_NPARTS; i++)
613 if (dp[i].dp_mid == DOSMID_386BSD) {
614 sl = BASE_SLICE + i;
615 break;
616 }
617 dsk.slice = sl;
618 }
619 if (sl != WHOLE_DISK_SLICE) {
620 dp += sl - BASE_SLICE;
621 if (dp->dp_mid != DOSMID_386BSD) {
622 printf("Invalid %s\n", "slice");
623 return -1;
624 }
625 dsk.start = dp->dp_scyl * dsk.head * dsk.sec +
626 dp->dp_shd * dsk.sec + dp->dp_ssect;
627 }
628 if (drvread(sec, dsk.start + LABELSECTOR))
629 return -1;
630 d = (void *)(sec + LABELOFFSET);
631 if (d->d_magic != DISKMAGIC || d->d_magic2 != DISKMAGIC) {
632 if (dsk.part != RAW_PART) {
633 printf("Invalid %s\n", "label");
634 return -1;
635 }
636 } else {
637 if (dsk.part >= d->d_npartitions ||
638 !d->d_partitions[dsk.part].p_size) {
639 printf("Invalid %s\n", "partition");
640 return -1;
641 }
642 dsk.start += d->d_partitions[dsk.part].p_offset;
643 dsk.start -= d->d_partitions[RAW_PART].p_offset;
644 }
645 unsliced: ;
646 }
647 for (p = buf; nblk; p += 512, lba++, nblk--) {
648 if ((i = drvread(p, dsk.start + lba)))
649 return i;
650 }
651 return 0;
652 }
653
654 static void
printf(const char * fmt,...)655 printf(const char *fmt,...)
656 {
657 va_list ap;
658 static char buf[10];
659 char *s;
660 unsigned u;
661 int c;
662
663 va_start(ap, fmt);
664 while ((c = *fmt++)) {
665 if (c == '%') {
666 c = *fmt++;
667 switch (c) {
668 case 'c':
669 putchar(va_arg(ap, int));
670 continue;
671 case 's':
672 for (s = va_arg(ap, char *); *s; s++)
673 putchar(*s);
674 continue;
675 case 'u':
676 u = va_arg(ap, unsigned);
677 s = buf;
678 do
679 *s++ = '0' + u % 10U;
680 while (u /= 10U);
681 while (--s >= buf)
682 putchar(*s);
683 continue;
684 }
685 }
686 putchar(c);
687 }
688 va_end(ap);
689 return;
690 }
691
692 static void
putchar(int c)693 putchar(int c)
694 {
695 if (c == '\n')
696 xputc('\r');
697 xputc(c);
698 }
699
700 static int
drvread(void * buf,unsigned lba)701 drvread(void *buf, unsigned lba)
702 {
703 static unsigned c = 0x2d5c7c2f;
704 unsigned bpc, x, cyl, head, sec;
705
706 bpc = dsk.sec * dsk.head;
707 cyl = lba / bpc;
708 x = lba % bpc;
709 head = x / dsk.sec;
710 sec = x % dsk.sec;
711
712 if (!OPT_CHECK(RBX_QUIET))
713 printf("%c\b", c = c << 8 | c >> 24);
714 v86.ctl = V86_ADDR | V86_CALLF | V86_FLAGS;
715 v86.addr = READORG; /* call to read in boot1 */
716 v86.ecx = cyl;
717 v86.edx = (head << 8) | sec;
718 v86.edi = lba;
719 v86.ebx = 512;
720 v86.es = VTOPSEG(buf);
721 v86.ebp = VTOPOFF(buf);
722 v86int();
723 v86.ctl = V86_FLAGS;
724 if (V86_CY(v86.efl)) {
725 printf("error %u c/h/s %u/%u/%u lba %u\n", v86.eax >> 8 & 0xff,
726 cyl, head, sec, lba);
727 return -1;
728 }
729 return 0;
730 }
731
732 static inline void
delay(void)733 delay(void)
734 {
735 int i;
736
737 i = 800;
738 do {
739 outb(0x5f, 0); /* about 600ns */
740 } while (--i >= 0);
741 }
742
743 static int
keyhit(unsigned sec)744 keyhit(unsigned sec)
745 {
746 unsigned i;
747
748 if (OPT_CHECK(RBX_NOINTR))
749 return 0;
750 for (i = 0; i < sec * 1000; i++) {
751 if (xgetc(1))
752 return 1;
753 delay();
754 }
755 return 0;
756 }
757
758 static int
xputc(int c)759 xputc(int c)
760 {
761 if (DO_KBD)
762 putc(c);
763 if (DO_SIO)
764 sio_putc(c);
765 return c;
766 }
767
768 static int
getc(int fn)769 getc(int fn)
770 {
771 v86.addr = 0x18;
772 v86.eax = fn << 8;
773 v86int();
774 if (fn)
775 return (v86.ebx >> 8) & 0x01;
776 else
777 return v86.eax & 0xff;
778 }
779
780 static int
xgetc(int fn)781 xgetc(int fn)
782 {
783 if (OPT_CHECK(RBX_NOINTR))
784 return 0;
785 for (;;) {
786 if (DO_KBD && getc(1))
787 return fn ? 1 : getc(0);
788 if (DO_SIO && sio_ischar())
789 return fn ? 1 : sio_getc();
790 if (fn)
791 return 0;
792 }
793 }
794