1 // 16bit code to load disk image and start system boot.
3 // Copyright (C) 2008 Kevin O'Connor <kevin@koconnor.net>
4 // Copyright (C) 2002 MandrakeSoft S.A.
6 // This file may be distributed under the terms of the GNU GPLv3 license.
8 #include "util.h" // irq_enable
9 #include "biosvar.h" // struct bregs
10 #include "config.h" // CONFIG_*
11 #include "cmos.h" // inb_cmos
13 //--------------------------------------------------------------------------
15 // displays the boot device
16 //--------------------------------------------------------------------------
18 static const char drivetypes[][10]={
19 "", "Floppy","Hard Disk","CD-Rom", "Network"
23 print_boot_device(u16 type)
25 /* NIC appears as type 0x80 */
26 if (type == IPL_TYPE_BEV)
28 if (type == 0 || type > 0x4)
29 BX_PANIC("Bad drive type\n");
30 printf("Booting from %s...\n", drivetypes[type]);
32 // XXX - latest cvs has BEV description
35 //--------------------------------------------------------------------------
37 // displays the reason why boot failed
38 //--------------------------------------------------------------------------
40 print_boot_failure(u16 type, u8 reason)
42 if (type == 0 || type > 0x3)
43 BX_PANIC("Bad drive type\n");
45 printf("Boot failed");
47 /* Report the reason too */
49 printf(": not a bootable disk");
51 printf(": could not read the boot disk");
59 SET_IPL(sequence, seq_nr);
64 if (CONFIG_ELTORITO_BOOT) {
65 bootdev = inb_cmos(CMOS_BIOS_BOOTFLAG2);
66 bootdev |= ((inb_cmos(CMOS_BIOS_BOOTFLAG1) & 0xf0) << 4);
67 bootdev >>= 4 * seq_nr;
70 BX_PANIC("No bootable device.\n");
72 /* Translate from CMOS runes to an IPL table offset by subtracting 1 */
76 BX_PANIC("No more boot devices.");
77 if (!!(inb_cmos(CMOS_BIOS_CONFIG) & 0x20) ^ (seq_nr == 1))
78 /* Boot from floppy if the bit is set or it's the second boot */
84 if (bootdev >= GET_IPL(count)) {
85 BX_INFO("Invalid boot device (0x%x)\n", bootdev);
88 u16 type = GET_IPL(table[bootdev].type);
90 /* Do the loading, and set up vector as a far pointer to the boot
91 * address, and bootdrv as the boot drive */
92 print_boot_device(type);
96 case IPL_TYPE_FLOPPY: /* FDD */
97 case IPL_TYPE_HARDDISK: /* HDD */
99 bootdrv = (type == IPL_TYPE_HARDDISK) ? 0x80 : 0x00;
103 memset(&cr, 0, sizeof(cr));
109 call16_int(0x13, &cr);
111 if (cr.flags & F_CF) {
112 print_boot_failure(type, 1);
116 /* Always check the signature on a HDD boot sector; on FDD,
117 * only do the check if the CMOS doesn't tell us to skip it */
118 if ((type != IPL_TYPE_FLOPPY)
119 || !((inb_cmos(CMOS_BIOS_BOOTFLAG1) & 0x01))) {
120 if (GET_FARVAR(bootseg, *(u16*)0x1fe) != 0xaa55) {
121 print_boot_failure(type, 0);
126 /* Canonicalize bootseg:bootip */
127 bootip = (bootseg & 0x0fff) << 4;
130 case IPL_TYPE_CDROM: /* CD-ROM */
135 /* Expansion ROM with a Bootstrap Entry Vector (a far
137 u32 vector = GET_IPL(table[bootdev].vector);
138 bootseg = vector >> 16;
139 bootip = vector & 0xffff;
146 memset(&cr, 0, sizeof(cr));
149 // Set the magic number in ax and the boot drive in dl.
154 // Boot failed: invoke the boot recovery function
155 memset(&cr, 0, sizeof(cr));
156 call16_int(0x18, &cr);
159 // Boot Failure recovery: try the next device.
164 u16 seq = GET_IPL(sequence) + 1;
168 // INT 19h Boot Load Service Entry Point
176 // Called from 32bit code - start boot process
182 memset(&br, 0, sizeof(br));
183 call16_int(0x19, &br);