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/* ----------------------------------------------------------------------- *
*
* Copyright 2009 Intel Corporation; author: H. Peter Anvin
*
* 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.
*
* Based on code from the Linux kernel:
*
* Copyright (C) 1991, 1992 Linus Torvalds
* Copyright 2007 rPath, Inc. - All Rights Reserved
*
* Original APM BIOS checking by Stephen Rothwell, May 1994
* (sfr@canb.auug.org.au)
*
* This file is part of the Linux kernel, and is made available under
* the terms of the GNU General Public License version 2.
*
* ----------------------------------------------------------------------- */
/*
* apm.c
*
* APM information for Multiboot
*/
#include "mboot.h"
#include <com32.h>
void mboot_apm(void)
{
static struct apm_info apm;
com32sys_t ireg, oreg;
memset(&ireg, 0, sizeof ireg);
ireg.eax.w[0] = 0x5300;
__intcall(0x15, &ireg, &oreg);
if (oreg.eflags.l & EFLAGS_CF)
return; /* No APM BIOS */
if (oreg.ebx.w[0] != 0x504d)
return; /* No "PM" signature */
if (!(oreg.ecx.w[0] & 0x02))
return; /* 32 bits not supported */
/* Disconnect first, just in case */
ireg.eax.b[0] = 0x04;
__intcall(0x15, &ireg, &oreg);
/* 32-bit connect */
ireg.eax.b[0] = 0x03;
__intcall(0x15, &ireg, &oreg);
apm.cseg = oreg.eax.w[0];
apm.offset = oreg.ebx.l;
apm.cseg_16 = oreg.ecx.w[0];
apm.dseg_16 = oreg.edx.w[0];
apm.cseg_len = oreg.esi.w[0];
apm.cseg_16_len = oreg.esi.w[1];
apm.dseg_16_len = oreg.edi.w[0];
/* Redo the installation check as the 32-bit connect;
some BIOSes return different flags this way... */
ireg.eax.b[0] = 0x00;
__intcall(0x15, &ireg, &oreg);
if ((oreg.eflags.l & EFLAGS_CF) || (oreg.ebx.w[0] != 0x504d)) {
/* Failure with 32-bit connect, try to disconect and ignore */
ireg.eax.b[0] = 0x04;
__intcall(0x15, &ireg, NULL);
return;
}
apm.version = oreg.eax.w[0];
mbinfo.apm_table = map_data(&apm, sizeof apm, 4, false);
if (mbinfo.apm_table)
mbinfo.flags |= MB_INFO_APM_TABLE;
}
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