Initial revision
This commit is contained in:
erich
parent
f397c4797c
commit
d2dee25f8c
2 changed files with 1177 additions and 0 deletions
561
shared_src/stage2.c
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561
shared_src/stage2.c
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/*
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* GRUB -- GRand Unified Bootloader
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* Copyright (C) 1996 Erich Boleyn <erich@uruk.org>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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#include "../shared_src/shared.h"
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char *
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get_entry(char *list, int num, int nested)
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{
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int i;
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for (i = 0; i < num; i++)
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{
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do
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{
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while (*(list++));
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}
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while (nested && *(list++));
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}
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return list;
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}
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void
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print_entries(int y, int size, int first, char *menu_entries)
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{
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int i;
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gotoxy(77, y+1);
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if (first)
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putchar(DISP_UP);
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else
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putchar(' ');
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get_entry(menu_entries, first, 0);
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for (i = 1; i <= size; i++)
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{
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int j = 0;
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gotoxy(3, y+i);
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while (*menu_entries)
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{
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if (j < 71)
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{
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putchar(*menu_entries);
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j++;
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}
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menu_entries++;
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}
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if (*(menu_entries-1))
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menu_entries++;
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for (; j < 71; j++)
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putchar(' ');
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}
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gotoxy(77, y+size);
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if (*menu_entries)
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putchar(DISP_DOWN);
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else
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putchar(' ');
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}
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void
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print_border(int y, int size)
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{
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int i;
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gotoxy(1, y);
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putchar(DISP_UL);
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for (i = 0; i < 73; i++)
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putchar(DISP_HORIZ);
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putchar(DISP_UR);
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i = 1;
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while (1)
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{
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gotoxy(1, y+i);
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if (i > size)
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break;
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putchar(DISP_VERT);
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gotoxy(75, y+i);
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putchar(DISP_VERT);
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i++;
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}
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putchar(DISP_LL);
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for (i = 0; i < 73; i++)
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putchar(DISP_HORIZ);
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putchar(DISP_LR);
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}
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void
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set_line(int y, int attr)
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{
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int x;
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for (x = 2; x < 75; x++)
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{
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gotoxy(x, y);
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set_attrib(attr);
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}
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}
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int timeout = -1;
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void
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run_menu(char *menu_entries, char *config_entries, int num_entries,
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char *heap, int entryno)
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{
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int c, time1, time2 = -1, first_entry = 0;
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char *cur_entry;
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/*
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* Main loop for menu UI.
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*/
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restart:
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while (entryno > 11)
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{
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first_entry++; entryno--;
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}
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init_page();
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print_border(3, 12);
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printf("\n
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Use the \x18 and \x19 keys for selecting which entry is highlighted.\n");
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if (config_entries)
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printf(" Press enter to boot the selected OS, \'e\' to edit the
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commands before booting, or \'c\' for a command-line.");
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else
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printf(
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" Press \'b\' to boot, enter to edit the selected command in the
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boot sequence, \'c\' for a command-line, \'o\' to open a new line
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after (\'O\' for before) the selected line, \'d\' to remove the
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selected line, or escape to go back to the main menu.");
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print_entries(3, 12, first_entry, menu_entries);
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/* invert initial line */
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set_line(4+entryno, 0x70);
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/* XX using RT clock now, need to initialize value */
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while ((time1 = getrtsecs()) == 0xFF);
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while (1)
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{
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/* initilize to NULL just in case... */
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cur_entry = NULL;
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if (timeout >= 0 && (time1 = getrtsecs()) != time2 && time1 != 0xFF)
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{
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if (timeout <= 0)
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{
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timeout = -1;
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break;
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}
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/* else not booting yet! */
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time2 = time1;
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gotoxy(3, 22);
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printf("The highlighted entry will be booted automatically in %d seconds. ", timeout);
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gotoxy(74, 4+entryno);
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timeout--;
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}
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if (checkkey() != -1)
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{
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c = getkey();
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if (timeout >= 0)
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{
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gotoxy(3, 22);
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printf(" ");
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timeout = -1;
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fallback = -1;
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gotoxy(74, 4+entryno);
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}
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if ((c == KEY_UP) || (ASCII_CHAR(c) == 16))
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{
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if (entryno > 0)
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{
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set_line(4+entryno, 0x7);
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entryno--;
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set_line(4+entryno, 0x70);
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}
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else if (first_entry > 0)
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{
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first_entry--;
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print_entries(3, 12, first_entry, menu_entries);
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set_line(4, 0x70);
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}
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}
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if ((c == KEY_DOWN) || (ASCII_CHAR(c) == 14)
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&& (first_entry+entryno+1) < num_entries)
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{
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if (entryno < 11)
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{
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set_line(4+entryno, 0x7);
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entryno++;
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set_line(4+entryno, 0x70);
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}
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else if (num_entries > 12+first_entry)
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{
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first_entry++;
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print_entries(3, 12, first_entry, menu_entries);
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set_line(15, 0x70);
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}
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}
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c = ASCII_CHAR(c);
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if (config_entries)
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{
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if ((c == '\n') || (c == '\r'))
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break;
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}
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else
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{
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if ((c == 'd') || (c == 'o') || (c == 'O'))
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{
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set_line(4+entryno, 0x7);
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/* insert after is almost exactly like insert before */
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if (c == 'o')
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{
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entryno++;
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c = 'O';
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}
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cur_entry = get_entry(menu_entries, first_entry+entryno, 0);
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if (c == 'O')
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{
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bcopy(cur_entry, cur_entry+2,
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((int)heap) - ((int)cur_entry));
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cur_entry[0] = ' ';
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cur_entry[1] = 0;
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heap += 2;
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num_entries++;
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}
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else if (num_entries > 0)
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{
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char *ptr = get_entry(menu_entries,
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first_entry+entryno+1, 0);
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bcopy(ptr, cur_entry, ((int)heap) - ((int)ptr));
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heap -= (((int)ptr) - ((int)cur_entry));
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num_entries--;
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if (entryno >= num_entries)
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entryno--;
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if (first_entry && num_entries < 12+first_entry)
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first_entry--;
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}
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print_entries(3, 12, first_entry, menu_entries);
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set_line(4+entryno, 0x70);
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}
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cur_entry = menu_entries;
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if (c == 27)
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return;
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if (c == 'b')
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break;
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}
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if ((config_entries && (c == 'e'))
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|| (!config_entries && ((c == '\n') || (c == '\r'))))
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{
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int num_entries = 0, i = 0;
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char *new_heap;
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if (config_entries)
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{
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new_heap = heap;
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cur_entry = get_entry(config_entries,
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first_entry+entryno, 1);
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}
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else
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{
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/* safe area! */
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new_heap = heap+1501;
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cur_entry = get_entry(menu_entries, first_entry+entryno, 0);
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}
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do
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{
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while (*(new_heap++) = cur_entry[i++]);
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num_entries++;
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}
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while (config_entries && cur_entry[i]);
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/* this only needs to be done if config_entries is non-NULL,
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but it doesn't hurt to do it always */
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*(new_heap++) = 0;
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if (config_entries)
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run_menu(heap, NULL, num_entries, new_heap, 0);
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else
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{
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cls();
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init_cmdline();
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new_heap = heap+1501;
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saved_drive = boot_drive;
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saved_partition = install_partition;
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current_drive = 0xFF;
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if (!get_cmdline("editing> ", commands, new_heap, 1501))
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{
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int j = 0;
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/* get length of new command */
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while (new_heap[j++]);
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if (j < 2)
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{
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j = 2;
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new_heap[0] = ' ';
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new_heap[1] = 0;
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}
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/* align rest of commands properly */
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bcopy(cur_entry+i, cur_entry+j,
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((int)heap) - (((int)cur_entry) + i));
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/* copy command to correct area */
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bcopy(new_heap, cur_entry, j);
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heap += (j - i);
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}
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}
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goto restart;
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}
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if (c == 'c')
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{
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enter_cmdline(NULL, heap);
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goto restart;
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}
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}
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}
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/*
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* Attempt to boot an entry.
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*/
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do
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{
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cls();
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if (config_entries)
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printf(" Booting \'%s\'\n\n",
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get_entry(menu_entries, first_entry+entryno, 0));
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else
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printf(" Booting command-list\n\n");
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if (!cur_entry)
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cur_entry = get_entry(config_entries, first_entry+entryno, 1);
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if (!(c = enter_cmdline(cur_entry, heap)))
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{
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cur_entry = NULL;
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first_entry = 0;
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entryno = fallback;
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fallback = -1;
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}
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}
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while (!c);
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goto restart;
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}
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static int
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get_line_from_config(char *cmdline, int maxlen)
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{
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int pos = 0, literal = 0, comment = 0;
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char c; /* since we're loading it a byte at a time! */
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while (read((int)&c, 1))
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{
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/* translate characters first! */
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if (c == '\\')
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{
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literal = 1;
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continue;
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}
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if (c == '\r')
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continue;
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if ((c == '\t') || (literal && (c == '\n')))
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c = ' ';
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literal = 0;
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if (comment)
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{
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if (c == '\n')
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comment = 0;
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}
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else if (!pos)
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{
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if (c == '#')
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comment = 1;
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else if ((c != ' ') && (c != '\n'))
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cmdline[pos++] = c;
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}
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else
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{
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if (c == '\n')
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break;
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if (pos < maxlen)
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cmdline[pos++] = c;
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}
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}
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cmdline[pos] = 0;
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return pos;
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}
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void
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cmain(void)
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{
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int config_len = 0, menu_len = 0;
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int num_entries = 0, default_entry = 0;
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char *config_entries = (char *)(mbi.mmap_addr + mbi.mmap_length);
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char *menu_entries = (char *)(BUFFERADDR + (32 * 1024));
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|
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/*
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* Here load the configuration file.
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*/
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if (open(config_file))
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{
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int state = 0, prev_config_len = 0, prev_menu_len = 0;
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char cmdline[1502], *ptr;
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while (get_line_from_config(cmdline, 1500))
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{
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ptr = skip_to(1, cmdline);
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|
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if (strcmp("title", cmdline) < 1)
|
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{
|
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if (state > 1)
|
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{
|
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num_entries++;
|
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config_entries[config_len++] = 0;
|
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prev_menu_len = menu_len;
|
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prev_config_len = config_len;
|
||||
}
|
||||
else
|
||||
{
|
||||
menu_len = prev_menu_len;
|
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config_len = prev_config_len;
|
||||
}
|
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|
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state = 1;
|
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|
||||
/* copy title into menu area */
|
||||
while (menu_entries[menu_len++] = *(ptr++));
|
||||
}
|
||||
else if (!state)
|
||||
{
|
||||
if (strcmp("timeout", cmdline) < 1)
|
||||
safe_parse_maxint(&ptr, &timeout);
|
||||
if (strcmp("fallback", cmdline) < 1)
|
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safe_parse_maxint(&ptr, &fallback);
|
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if (strcmp("default", cmdline) < 1)
|
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safe_parse_maxint(&ptr, &default_entry);
|
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|
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errnum = 0;
|
||||
}
|
||||
else
|
||||
{
|
||||
int i = 0;
|
||||
|
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state++;
|
||||
|
||||
/* copy config file data to config area */
|
||||
while (config_entries[config_len++] = cmdline[i++]);
|
||||
}
|
||||
}
|
||||
|
||||
if (state > 1)
|
||||
{
|
||||
num_entries++;
|
||||
config_entries[config_len++] = 0;
|
||||
}
|
||||
else
|
||||
{
|
||||
menu_len = prev_menu_len;
|
||||
config_len = prev_config_len;
|
||||
}
|
||||
|
||||
menu_entries[menu_len++] = 0;
|
||||
config_entries[config_len++] = 0;
|
||||
|
||||
bcopy(menu_entries, config_entries+config_len, menu_len);
|
||||
|
||||
menu_entries = config_entries+config_len;
|
||||
}
|
||||
|
||||
/*
|
||||
* If no acceptable config file, goto command-line, starting heap from
|
||||
* where the config entries would have been stored if there were any.
|
||||
*/
|
||||
|
||||
if (!num_entries)
|
||||
while (1)
|
||||
enter_cmdline(NULL, config_entries);
|
||||
|
||||
/*
|
||||
* Run menu interface (this shouldn't return!).
|
||||
*/
|
||||
|
||||
run_menu(menu_entries, config_entries, num_entries,
|
||||
menu_entries+menu_len, default_entry);
|
||||
}
|
||||
|
||||
|
||||
616
stage1/stage1.S
Normal file
616
stage1/stage1.S
Normal file
|
|
@ -0,0 +1,616 @@
|
|||
/*
|
||||
* GRUB -- GRand Unified Bootloader
|
||||
* Copyright (C) 1996 Erich Boleyn <erich@uruk.org>
|
||||
*
|
||||
* This program is free software; you can redistribute it and/or modify
|
||||
* it under the terms of the GNU General Public License as published by
|
||||
* the Free Software Foundation; either version 2 of the License, or
|
||||
* (at your option) any later version.
|
||||
*
|
||||
* This program is distributed in the hope that it will be useful,
|
||||
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
||||
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
||||
* GNU General Public License for more details.
|
||||
*
|
||||
* You should have received a copy of the GNU General Public License
|
||||
* along with this program; if not, write to the Free Software
|
||||
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
|
||||
*/
|
||||
|
||||
/*
|
||||
* defines for the code go here
|
||||
*/
|
||||
|
||||
#define SIGNATURE 0xaa55
|
||||
#define BPBEND 0x3e
|
||||
#define PARTSTART 0x1be /* starting address of partition table */
|
||||
#define PARTEND 0x1fe /* ending addres of the partition table */
|
||||
#define MINPARAMSIZ 18 /* size of extra data parameters */
|
||||
#define LISTSIZ 8 /* size of sector list */
|
||||
#define REALSTACK 0x2000 /* stack for this code and BIOS calls */
|
||||
#define BUFFERSEG 0x7000 /* segment address of disk buffer, the
|
||||
disk buffer MUST be 32K long and cannot
|
||||
straddle a 64K boundary */
|
||||
#define BIOS_HD_FLAG 0x80 /* bit set in BIOS drive number to designate
|
||||
a hard disk vs. a floppy */
|
||||
|
||||
/* data for debugging */
|
||||
#define CHAR_1 '1'
|
||||
#define CHAR_2 '2'
|
||||
#define CHAR_3 '3'
|
||||
#define CHAR_4 '4'
|
||||
#define CHAR_5 '5'
|
||||
#define CHAR_6 '6'
|
||||
#define CHAR_a 'a'
|
||||
|
||||
/* messages displayed at all times */
|
||||
#define CHAR_S 'S'
|
||||
#define CHAR_J 'J'
|
||||
|
||||
/* error messages */
|
||||
|
||||
/* Read error (trying to read non-existent sector, perhaps) */
|
||||
#define CHAR_R 'R'
|
||||
/* Geometry translation error (off of probed geometry) */
|
||||
#define CHAR_G 'G'
|
||||
/* Disk geometry probe failed! */
|
||||
#define CHAR_P 'P'
|
||||
|
||||
/* Absolute addresses
|
||||
This makes the assembler generate the address without support
|
||||
from the linker. (ELF can't relocate 16bit addresses!) */
|
||||
#define ABS(x) (x-_start+0x7c00)
|
||||
|
||||
/* Relative addresses (for jumps)
|
||||
These macros use the local label 0, so start with your local
|
||||
label at 1! */
|
||||
#define REL(x) .word x-0f; 0:
|
||||
#define RELB(x) .byte x-0f; 0:
|
||||
|
||||
/* Print message
|
||||
movb $x, %al; call message */
|
||||
#define MSG(x) movb $x, %al; .byte 0xe8; REL(message)
|
||||
|
||||
.file "stage1.S"
|
||||
|
||||
.text
|
||||
|
||||
/*
|
||||
* The ".code16" directive only works in GAS, the GNU assembler!
|
||||
* This adds 32-bit data or addressing directives so that this
|
||||
* code will work in real mode!
|
||||
*/
|
||||
.code16
|
||||
|
||||
.globl _start; _start:
|
||||
/*
|
||||
* _start is loaded at 0x7c00 and is jumped to with CS:IP 0:0x7c00
|
||||
*/
|
||||
|
||||
/*
|
||||
* Beginning of the sector is compatible with the FAT/HPFS BIOS
|
||||
* parameter block.
|
||||
*/
|
||||
|
||||
/* jmp after_BPB */
|
||||
.byte 0xeb; RELB(after_BPB)
|
||||
nop /* do I care about this ??? */
|
||||
|
||||
/*
|
||||
* This space is for the BIOS parameter block!!!! Don't change
|
||||
* the first jump, nor start the code anywhere but right after
|
||||
* this area.
|
||||
*/
|
||||
|
||||
. = _start + 4
|
||||
|
||||
/* scratch space */
|
||||
sectors:
|
||||
.word 0
|
||||
heads:
|
||||
.word 0
|
||||
cylinders:
|
||||
.word 0
|
||||
/* more space... */
|
||||
|
||||
. = _start + BPBEND
|
||||
|
||||
/*
|
||||
* End of BIOS parameter block.
|
||||
*/
|
||||
|
||||
after_BPB:
|
||||
|
||||
/* general setup */
|
||||
|
||||
/* set up %ds and %ss as offset from 0 */
|
||||
xorw %ax, %ax
|
||||
movw %ax, %ds
|
||||
movw %ax, %es
|
||||
|
||||
cld /* sets the copy direction to forward */
|
||||
|
||||
/* set up the REAL stack */
|
||||
movw %ax, %ss
|
||||
movw $REALSTACK, %sp
|
||||
|
||||
/*
|
||||
* Check if we have a forced disk reference here
|
||||
*/
|
||||
/* movb firstlist, %al */
|
||||
.byte 0xa0; .word ABS(firstlist)
|
||||
cmpb $0xff, %al
|
||||
/* je 1f */
|
||||
.byte 0x74; RELB(1f)
|
||||
movb %al, %dl
|
||||
1:
|
||||
/* save drive reference first thing! */
|
||||
pushw %dx
|
||||
|
||||
/* tell the user that we're here before anything else! */
|
||||
MSG(CHAR_S)
|
||||
|
||||
#ifndef BIOS_PROBE_ONLY
|
||||
/*
|
||||
* Jump to floppy probe instead of the hard disk probe ?
|
||||
*/
|
||||
movb %dl, %al
|
||||
andb $BIOS_HD_FLAG, %al
|
||||
|
||||
/* jz floppy_probe */
|
||||
.byte 0x0f, 0x84; REL(floppy_probe)
|
||||
#endif
|
||||
|
||||
#ifdef DEBUG
|
||||
MSG(CHAR_6)
|
||||
#endif
|
||||
|
||||
/*
|
||||
* Determine the hard disk geometry from the BIOS!
|
||||
*/
|
||||
movb $8, %ah
|
||||
int $0x13
|
||||
|
||||
/* if BIOS geometry call fails, display error and die! */
|
||||
/* jc probe_error (16-bit)*/
|
||||
.byte 0x0f, 0x82; REL(probe_error)
|
||||
|
||||
final_init:
|
||||
xorb %ah, %ah
|
||||
movb %dh, %al
|
||||
incw %ax
|
||||
|
||||
/* movw %ax, heads */ /* save num heads */
|
||||
.byte 0xA3; .word ABS(heads)
|
||||
|
||||
xorw %dx, %dx
|
||||
movb %cl, %dl
|
||||
shlw $2, %dx
|
||||
movb %ch, %al
|
||||
movb %dh, %ah
|
||||
|
||||
incw %ax
|
||||
|
||||
/* movw %ax, cylinders */ /* save num cylinders */
|
||||
.byte 0xA3; .word ABS(cylinders)
|
||||
|
||||
xorw %ax, %ax
|
||||
movb %dl, %al
|
||||
shrb $2, %al
|
||||
|
||||
/* save a byte on addressing by moving this forward ?? */
|
||||
movw $ABS(sectors), %si
|
||||
|
||||
/* movw %ax, (%si) */ /* save num sectors */
|
||||
.byte 0x89, 0x04
|
||||
|
||||
/* this sets up for the first run through "bootloop" */
|
||||
movw $ABS(firstlist), %di
|
||||
|
||||
|
||||
/* this is the loop for reading the secondary boot-loader in */
|
||||
bootloop:
|
||||
|
||||
#ifdef DEBUG
|
||||
MSG(CHAR_2)
|
||||
#endif
|
||||
|
||||
/* update position to load from */
|
||||
subw $LISTSIZ, %di
|
||||
|
||||
/* cmpw $0, 4(%di) */ /* check the number of sectors to read */
|
||||
.byte 0x81, 0x7d, 0x04; .word 0
|
||||
|
||||
/* je bootit (16-bit)*/ /* if zero, go to the start function */
|
||||
.byte 0x0f, 0x84; REL(bootit)
|
||||
|
||||
/* movl (%di), %ax */ /* load logical sector start (bottom half) */
|
||||
.byte 0x8b, 0x05
|
||||
|
||||
/* movl 2(%di), %dx */ /* load logical sector start (top half) */
|
||||
.byte 0x8b, 0x55, 0x02
|
||||
|
||||
/* divw (%si), %dx:%ax */ /* divide by number of sectors */
|
||||
.byte 0xf7, 0x34
|
||||
|
||||
/* movb %dl, (%di) */ /* save sector start */
|
||||
.byte 0x88, 0x15
|
||||
|
||||
xorw %dx, %dx /* zero %dx */
|
||||
/* divw 2(%si), %dx:%ax */ /* divide by number of heads */
|
||||
.byte 0xf7, 0x74, 0x02
|
||||
|
||||
/* movb %dl, 1(%di) */ /* save head start */
|
||||
.byte 0x88, 0x55, 0x01
|
||||
|
||||
/* movw %ax, 2(%di) */ /* save cylinder start */
|
||||
.byte 0x89, 0x45, 0x02
|
||||
|
||||
/* cmpw 4(%si), %ax */ /* do we need too many cylinders? */
|
||||
.byte 0x3b, 0x44, 0x04
|
||||
|
||||
/* jge geometry_error (16-bit) */
|
||||
.byte 0x0f, 0x8d; REL(geometry_error)
|
||||
|
||||
setup_sectors:
|
||||
|
||||
#ifdef DEBUG
|
||||
MSG(CHAR_3)
|
||||
#endif
|
||||
|
||||
/* determine the maximum sector length of this read */
|
||||
/* movw (%si), %ax */ /* get number of sectors per track/head */
|
||||
.byte 0x8b, 0x04
|
||||
|
||||
/* subb (%di), %al */ /* subtract sector start */
|
||||
.byte 0x2a, 0x05
|
||||
|
||||
/* how many do we really want to read? */
|
||||
/* cmpw %ax, 4(%di) */ /* compare against total number of sectors */
|
||||
.byte 0x39, 0x45, 0x04
|
||||
|
||||
/* jg more_sectors (8-bit)*/ /* which is greater? */
|
||||
.byte 0x7f; RELB(more_sectors)
|
||||
|
||||
/* movw 4(%di), %ax */ /* if less than, set to total */
|
||||
.byte 0x8b, 0x45, 0x04
|
||||
|
||||
#ifdef DEBUG
|
||||
pushw %ax
|
||||
MSG(CHAR_4)
|
||||
popw %ax
|
||||
#endif
|
||||
|
||||
more_sectors:
|
||||
/* subw %ax, 4(%di) */ /* subtract from total */
|
||||
.byte 0x29, 0x45, 0x04
|
||||
|
||||
/* this is the loop for taking care of BIOS translation (ugh!) */
|
||||
|
||||
#ifdef DEBUG
|
||||
pushw %ax
|
||||
addb $CHAR_a, %al
|
||||
/* call message */
|
||||
.byte 0xe8; REL(message)
|
||||
popw %ax
|
||||
#endif
|
||||
|
||||
/* movb 3(%di), %dl */ /* get high bits of cylinder */
|
||||
.byte 0x8a, 0x55, 0x03
|
||||
|
||||
shlb $6, %dl /* shift left by 6 bits */
|
||||
/* movw (%di), %cl */ /* get sector */
|
||||
.byte 0x8b, 0x0d
|
||||
|
||||
incb %cl /* normalize sector (sectors go
|
||||
from 1-N, not 0-(N-1) ) */
|
||||
orb %dl, %cl /* composite together */
|
||||
/* movb 2(%di), %ch */ /* sector+hcyl in cl, cylinder in ch */
|
||||
.byte 0x8a, 0x6d, 0x02
|
||||
|
||||
/* restore %dx */
|
||||
popw %dx
|
||||
pushw %dx
|
||||
|
||||
/* movb 1(%di), %dh */ /* head num */
|
||||
.byte 0x8a, 0x75, 0x01
|
||||
|
||||
pushw %ax /* save %ax from destruction! */
|
||||
|
||||
/*
|
||||
* BIOS call "INT 0x13 Function 0x2" to read sectors from disk into memory
|
||||
* Call with %ah = 0x2
|
||||
* %al = number of sectors
|
||||
* %ch = cylinder
|
||||
* %cl = sector (bits 6-7 are high bits of "cylinder")
|
||||
* %dh = head
|
||||
* %dl = drive (0x80 for hard disk, 0x0 for floppy disk)
|
||||
* %es:%bx = segment:offset of buffer
|
||||
* Return:
|
||||
* %al = 0x0 on success; err code on failure
|
||||
*/
|
||||
|
||||
movw $BUFFERSEG, %bx
|
||||
movw %bx, %es /* load %es segment with disk buffer */
|
||||
|
||||
xorw %bx, %bx /* %bx = 0, put it at 0 in the segment */
|
||||
movb $0x2, %ah /* function 2 */
|
||||
int $0x13
|
||||
|
||||
/* jc read_error */
|
||||
.byte 0x72
|
||||
RELB(read_error)
|
||||
|
||||
/* load addresses for copy from disk buffer to destination */
|
||||
/* movw 6(%di), %es */ /* load destination segment */
|
||||
.byte 0x8e, 0x45, 0x06
|
||||
|
||||
movw $BUFFERSEG, %ax
|
||||
movw %ax, %fs /* load source segment */
|
||||
|
||||
/* restore %ax */
|
||||
popw %ax
|
||||
|
||||
/* determine the next possible destination address (presuming
|
||||
512 byte sectors!) */
|
||||
shlw $5, %ax /* shift %ax five bits to the left */
|
||||
/* addw %ax, 6(%di) */ /* add the corrected value to the destination
|
||||
address for next time */
|
||||
.byte 0x01, 0x45, 0x06
|
||||
|
||||
/* get the copy length */
|
||||
shlw $4, %ax
|
||||
movw %ax, %cx
|
||||
|
||||
/* save addressing regs */
|
||||
pushw %si
|
||||
pushw %di
|
||||
|
||||
xorw %di, %di /* zero offset of destination addresses */
|
||||
xorw %si, %si /* zero offset of source addresses */
|
||||
|
||||
/* perform copy */
|
||||
rep /* sets a repeat */
|
||||
fs /* this overrides the source segment from %ds to %fs */
|
||||
movsb /* this runs the actual copy */
|
||||
|
||||
/* restore addressing regs */
|
||||
popw %di
|
||||
popw %si
|
||||
|
||||
/* check if finished with this dataset */
|
||||
/* cmpw $0, 4(%di) */
|
||||
.byte 0x81, 0x7d, 0x04; .word 0
|
||||
|
||||
/* je bootloop */
|
||||
.byte 0x0f, 0x84; REL(bootloop)
|
||||
|
||||
#ifdef DEBUG
|
||||
MSG(CHAR_5)
|
||||
#endif
|
||||
|
||||
/* find out the next BIOS set to load in */
|
||||
/* movb $0, (%di) */ /* set the sector start */
|
||||
.byte 0xc6, 0x05, 0
|
||||
|
||||
xorb %ah, %ah /* zero %ah */
|
||||
/* movb 1(%di), %al */ /* load head number into %al */
|
||||
.byte 0x8a, 0x45, 0x01
|
||||
|
||||
incw %ax /* increment current head number */
|
||||
/* cmpw 2(%si), %ax */ /* compare to total number of heads */
|
||||
.byte 0x3b, 0x44, 0x02
|
||||
|
||||
/* jne update_heads (8-bit)*/
|
||||
.byte 0x75; RELB(update_heads)
|
||||
|
||||
/* movw 2(%di), %ax */ /* load cylinder number into %ax */
|
||||
.byte 0x8b, 0x45, 0x02
|
||||
|
||||
incw %ax /* increment current cylinder number */
|
||||
/* cmpw 4(%si), %ax */ /* compare to total number of cylinders */
|
||||
.byte 0x3b, 0x44, 0x04
|
||||
|
||||
/* je geometry_error */ /* display error and die if greater */
|
||||
.byte 0x74; RELB(geometry_error)
|
||||
|
||||
/* movw %ax, 2(%di) */ /* store new cylinder number */
|
||||
.byte 0x89, 0x45, 0x02
|
||||
|
||||
movb $0, %al /* for storing new head number */
|
||||
|
||||
update_heads:
|
||||
/* movb %al, 1(%di) */ /* store new head number */
|
||||
.byte 0x88, 0x45, 0x01
|
||||
|
||||
#ifdef DEBUG
|
||||
addb $CHAR_a, %al
|
||||
/* call message */
|
||||
.byte 0xe8; REL(message)
|
||||
|
||||
/* movb 2(%di), %al */
|
||||
.byte 0x8a, 0x45, 0x02
|
||||
|
||||
addb $CHAR_a, %al
|
||||
/* call message */
|
||||
.byte 0xe8; REL(message)
|
||||
#endif
|
||||
|
||||
/* jump to "setup_sectors" to determine length of the new read */
|
||||
/* jmp setup_sectors */
|
||||
.byte 0xe9; REL(setup_sectors)
|
||||
|
||||
/*
|
||||
* BIOS Geometry translation error (past the end of the disk geometry!).
|
||||
*/
|
||||
geometry_error:
|
||||
movb $CHAR_G, %al
|
||||
/* jmp display_error (8-bit) */
|
||||
.byte 0xeb; RELB(display_error)
|
||||
|
||||
/*
|
||||
* Disk probe failure.
|
||||
*/
|
||||
probe_error:
|
||||
movb $CHAR_P, %al
|
||||
/* jmp display_error (8-bit) */
|
||||
.byte 0xeb; RELB(display_error)
|
||||
|
||||
/*
|
||||
* Read error on the disk.
|
||||
*/
|
||||
read_error:
|
||||
movb $CHAR_R, %al
|
||||
|
||||
display_error:
|
||||
/* call message */
|
||||
.byte 0xe8; REL(message)
|
||||
|
||||
/* go here when you need to stop the machine hard after an error condition */
|
||||
stop: /* jmp stop (8-bit) */
|
||||
.byte 0xeb; RELB(stop)
|
||||
|
||||
|
||||
/*
|
||||
* message: write the character in %al to the console, %ah gets trashed.
|
||||
*/
|
||||
message:
|
||||
/*
|
||||
* Use BIOS "int 10H Function 0Eh" to write character in teletype mode
|
||||
* %ah = 0xe %al = character
|
||||
* %bh = page %bl = foreground color (graphics modes)
|
||||
*/
|
||||
|
||||
pushw %bx
|
||||
movw $0x0001, %bx
|
||||
movb $0xe, %ah
|
||||
int $0x10 /* display a byte */
|
||||
popw %bx
|
||||
|
||||
/* ret */
|
||||
.byte 0xc3
|
||||
lastlist:
|
||||
|
||||
/*
|
||||
* This data area is for keeping general parameters.
|
||||
*/
|
||||
. = _start + PARTSTART - MINPARAMSIZ - LISTSIZ
|
||||
|
||||
/* this next data area before the partition area is specifically
|
||||
sized, you should update "MINPARAMSIZ" to reflect any additions
|
||||
or deletions to this area */
|
||||
|
||||
.word 0
|
||||
.word 0
|
||||
|
||||
/* fill the first data listing with the default */
|
||||
#ifdef FFS_STAGE1_5
|
||||
.long 2 /* this is the sector start parameter, in logical
|
||||
sectors from the start of the disk, sector 0 */
|
||||
.word 14 /* this is the number of sectors to read */
|
||||
.word 0x0200 /* this is the segment of the starting address
|
||||
to load the data into */
|
||||
#else
|
||||
.long 1 /* this is the sector start parameter, in logical
|
||||
sectors from the start of the disk, sector 0 */
|
||||
.word 64 /* this is the number of sectors to read */
|
||||
.word 0x0800 /* this is the segment of the starting address
|
||||
to load the data into */
|
||||
#endif
|
||||
firstlist:
|
||||
.byte 0xff /* the disk to load stage2 from */
|
||||
/* 0xff means use the boot drive */
|
||||
/* the above label has to be after its data!!! */
|
||||
|
||||
/*
|
||||
* Jump here when all data loading is done.
|
||||
*/
|
||||
|
||||
bootit:
|
||||
|
||||
/*
|
||||
* Tell the user we're going to the next stage...
|
||||
*/
|
||||
MSG(CHAR_J)
|
||||
|
||||
popw %dx /* this makes sure %dl is our "boot" drive */
|
||||
|
||||
/*
|
||||
* ljmp to the second stage boot loader.
|
||||
*/
|
||||
|
||||
/* ljmp $myoffset, $myseg */
|
||||
.byte 0xea
|
||||
#ifdef STAGE1_5
|
||||
.word 0x2000, 0
|
||||
#else
|
||||
.word 0x8000, 0
|
||||
#endif
|
||||
|
||||
/*
|
||||
* This is the compatibility version number.
|
||||
*
|
||||
* DO NOT MOVE THIS!!!
|
||||
*/
|
||||
.byte 1, 0
|
||||
|
||||
/*
|
||||
* This is where an MBR would go if on a hard disk. The code
|
||||
* here isn't even referenced unless we're on a floppy. Kinda
|
||||
* sneaky, huh?
|
||||
*/
|
||||
|
||||
. = _start + PARTSTART
|
||||
|
||||
#ifndef BIOS_PROBE_ONLY
|
||||
probe_values:
|
||||
.byte 36, 18, 15, 9, 0
|
||||
|
||||
floppy_probe:
|
||||
/*
|
||||
* Perform floppy probe!
|
||||
*/
|
||||
|
||||
movw $ABS(probe_values-1), %si
|
||||
|
||||
probe_loop:
|
||||
/* reset floppy controller INT 13h AH=0 */
|
||||
xorw %ax, %ax
|
||||
int $0x13
|
||||
|
||||
incw %si
|
||||
|
||||
/* movb (%si), %cl */
|
||||
.byte 0x8a, 0x0c
|
||||
|
||||
/* if number of sectors is 0, display error and die */
|
||||
cmpb $0, %cl
|
||||
|
||||
/* je probe_error (16-bit)*/
|
||||
.byte 0x0f, 0x84; REL(probe_error)
|
||||
|
||||
/* perform read */
|
||||
movw $REALSTACK, %bx
|
||||
movw $0x201, %ax
|
||||
movb $0, %ch
|
||||
movb $0, %dh
|
||||
int $0x13
|
||||
|
||||
/* if error, jump to "probe_loop" */
|
||||
/* jc probe_loop (8-bit)*/
|
||||
.byte 0x72; RELB(probe_loop)
|
||||
|
||||
/* %cl is already the correct value! */
|
||||
movb $1, %dh
|
||||
movb $79, %ch
|
||||
|
||||
/* jmp final_init */
|
||||
.byte 0xe9; REL(final_init)
|
||||
|
||||
#endif /* !BIOS_PROBE_ONLY */
|
||||
|
||||
. = _start + PARTEND
|
||||
|
||||
/* the last 2 bytes in the sector 0 contain the signature */
|
||||
.word SIGNATURE
|
||||
|
||||
Loading…
Add table
Add a link
Reference in a new issue