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 "ata.h" // ata_detect
12 #include "disk.h" // cdrom_boot
14 // We need a copy of this string, but we are not actually a PnP BIOS,
15 // so make sure it is *not* aligned, so OSes will not see it if they
17 char pnp_string[] VISIBLE16 __attribute__((aligned (2))) = " $PnP";
19 //--------------------------------------------------------------------------
21 // displays the boot device
22 //--------------------------------------------------------------------------
24 static const char drivetypes[][10]={
25 "", "Floppy", "Hard Disk", "CD-Rom", "Network"
29 printf_bootdev(u16 bootdev)
31 u16 type = GET_EBDA(ipl.table[bootdev].type);
33 /* NIC appears as type 0x80 */
34 if (type == IPL_TYPE_BEV)
36 if (type == 0 || type > 0x4)
37 BX_PANIC("Bad drive type\n");
38 printf("%s", drivetypes[type]);
40 /* print product string if BEV */
41 void *far_description = (void*)GET_EBDA(ipl.table[bootdev].description);
42 if (type == 4 && far_description != 0) {
44 /* first 32 bytes are significant */
45 memcpy(MAKE_FARPTR(GET_SEG(SS), &description), far_description, 32);
46 /* terminate string */
48 printf(" [%.s]", description);
53 print_boot_device(u16 bootdev)
55 printf("Booting from ");
56 printf_bootdev(bootdev);
60 //--------------------------------------------------------------------------
62 // displays the reason why boot failed
63 //--------------------------------------------------------------------------
65 print_boot_failure(u16 type, u8 reason)
67 if (type == 0 || type > 0x3)
68 BX_PANIC("Bad drive type\n");
70 printf("Boot failed");
72 /* Report the reason too */
74 printf(": not a bootable disk");
76 printf(": could not read the boot disk");
86 SET_EBDA(ipl.sequence, seq_nr);
88 u32 bootdev = GET_EBDA(ipl.bootorder);
89 bootdev >>= 4 * seq_nr;
93 BX_PANIC("No bootable device.\n");
95 /* Translate bootdev to an IPL table offset by subtracting 1 */
98 if (bootdev >= GET_EBDA(ipl.count)) {
99 dprintf(1, "Invalid boot device (0x%x)\n", bootdev);
103 /* Do the loading, and set up vector as a far pointer to the boot
104 * address, and bootdrv as the boot drive */
105 print_boot_device(bootdev);
107 u16 type = GET_EBDA(ipl.table[bootdev].type);
113 case IPL_TYPE_FLOPPY: /* FDD */
114 case IPL_TYPE_HARDDISK: /* HDD */
116 bootdrv = (type == IPL_TYPE_HARDDISK) ? 0x80 : 0x00;
120 memset(&cr, 0, sizeof(cr));
126 call16_int(0x13, &cr);
128 if (cr.flags & F_CF) {
129 print_boot_failure(type, 1);
133 /* Always check the signature on a HDD boot sector; on FDD,
134 * only do the check if configured for it */
135 if (type != IPL_TYPE_FLOPPY || GET_EBDA(ipl.checkfloppysig)) {
136 if (GET_FARVAR(bootseg, *(u16*)0x1fe) != 0xaa55) {
137 print_boot_failure(type, 0);
142 /* Canonicalize bootseg:bootip */
143 bootip = (bootseg & 0x0fff) << 4;
146 case IPL_TYPE_CDROM: {
148 if (! CONFIG_CDROM_BOOT)
150 u16 status = cdrom_boot();
152 printf("CDROM boot failure code : %04x\n", status);
153 print_boot_failure(type, 1);
157 bootdrv = GET_EBDA(cdemu.emulated_drive);
158 bootseg = GET_EBDA(cdemu.load_segment);
159 /* Canonicalize bootseg:bootip */
160 bootip = (bootseg & 0x0fff) << 4;
165 /* Expansion ROM with a Bootstrap Entry Vector (a far
167 u32 vector = GET_EBDA(ipl.table[bootdev].vector);
168 bootseg = vector >> 16;
169 bootip = vector & 0xffff;
177 dprintf(1, "Booting from %x:%x\n", bootseg, bootip);
179 memset(&cr, 0, sizeof(cr));
182 // Set the magic number in ax and the boot drive in dl.
193 // Boot failed: invoke the boot recovery function
195 memset(&br, 0, sizeof(br));
196 call16_int(0x18, &br);
199 // Boot Failure recovery: try the next device.
203 debug_enter(NULL, DEBUG_HDL_18);
204 u16 seq = GET_EBDA(ipl.sequence) + 1;
208 // INT 19h Boot Load Service Entry Point
212 debug_enter(NULL, DEBUG_HDL_19);