blob: 0b8769e4a117becb737168352fb75bca2b065c26 [file] [log] [blame]
/* -----------------------------------------------------------------------
*
* Copyright 1999-2008 H. Peter Anvin - All Rights Reserved
*
* 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, Inc., 51 Franklin St, Fifth Floor,
* Boston MA 02110-1301, USA; either version 2 of the License, or
* (at your option) any later version; incorporated herein by reference.
*
* -----------------------------------------------------------------------
*/
#include <sys/cpu.h>
#include <sys/io.h>
#include <string.h>
#include <core.h>
#include <fs.h>
#include <bios.h>
#include <syslinux/video.h>
/*
* localboot.c
*
* Boot from a local disk, or invoke INT 18h.
*/
#define LOCALBOOT_MSG "Booting from local disk..."
#define retry_count 16
extern void local_boot16(void);
/*
* Boot a specified local disk. AX specifies the BIOS disk number; or
* -1 in case we should execute INT 18h ("next device.")
*/
__export void local_boot(int16_t ax)
{
com32sys_t ireg, oreg;
int i;
memset(&ireg, 0, sizeof(ireg));
syslinux_force_text_mode();
writestr(LOCALBOOT_MSG);
crlf();
cleanup_hardware();
if (ax == -1) {
/* Hope this does the right thing */
__intcall(0x18, &zero_regs, NULL);
/* If we returned, oh boy... */
kaboom();
}
/*
* Load boot sector from the specified BIOS device and jump to
* it.
*/
memset(&ireg, 0, sizeof ireg);
ireg.edx.b[0] = ax & 0xff;
ireg.eax.w[0] = 0; /* Reset drive */
__intcall(0x13, &ireg, NULL);
memset(&ireg, 0, sizeof(ireg));
ireg.eax.w[0] = 0x0201; /* Read one sector */
ireg.ecx.w[0] = 0x0001; /* C/H/S = 0/0/1 (first sector) */
ireg.ebx.w[0] = OFFS(trackbuf);
ireg.es = SEG(trackbuf);
for (i = 0; i < retry_count; i++) {
__intcall(0x13, &ireg, &oreg);
if (!(oreg.eflags.l & EFLAGS_CF))
break;
}
if (i == retry_count)
kaboom();
cli(); /* Abandon hope, ye who enter here */
memcpy((void *)0x07C00, trackbuf, 512);
ireg.esi.w[0] = OFFS(trackbuf);
ireg.edi.w[0] = 0x07C00;
ireg.edx.w[0] = ax;
call16(local_boot16, &ireg, NULL);
}