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/*
* Copyright (C) 2005 Josef Cejka
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* - Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* - Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* - The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <arch/boot/memmapasm.h>
E820_RECORD_SIZE = MEMMAP_E820_RECORD_SIZE
E820_MAX_RECORDS = MEMMAP_E820_MAX_RECORDS
E820_SMAP = 0x534d4150
.global memmap_arch_init
.global e820counter
.global e820table
.global e801memorysize
.code16
.section K_TEXT_START_2
memmap_arch_init:
e820begin:
xorl %ebx,%ebx # during first call, ebx must be 0
movw %bx,%ds
movw %bx,%es
movw $e820table,%di
movb $E820_MAX_RECORDS,e820counter
e820loop:
movl $E820_SMAP,%edx # control sequence "SMAP"
movl $0x0000e820,%eax # service
movl $E820_RECORD_SIZE,%ecx
int $0x15
jc e820err
cmpl $E820_SMAP,%eax # verifying BIOS
jne e820err
cmpl $E820_RECORD_SIZE,%ecx
jne e820err # bad record size - bug in bios
movw %di,%ax # next record
addw $E820_RECORD_SIZE,%ax
movw %ax,%di
decb e820counter # buffer is full
jz e820end
cmpl $0,%ebx
jne e820loop
e820end:
movb $E820_MAX_RECORDS,%al
subb e820counter,%al
movb %al,e820counter # store # of valid entries in e820counter
jmp e801begin
e820err:
movb $0,e820counter
# method e801 - get size of memory
e801begin:
xorw %dx,%dx
xorw %cx,%cx
xorw %bx,%bx
movw $0xe801,%ax
stc
int $0x15
jc e801end
# fix problem with some BIOSes which use ax:bx rather than cx:dx
testw %cx,%cx
jnz e801cxdx
testw %dx,%dx
jnz e801cxdx
movw %ax,%cx
movw %bx,%dx
e801cxdx:
andl $0xffff,%edx
shll $6,%edx
andl $0xffff,%ecx
addl %ecx,%edx
addl $0x0400,%edx # add lower 1 MB - it's not included by e801 method
movl %edx,e801memorysize
e801end:
ret
#memory size in 1 kb chunks
e801memorysize:
.long 0
e820counter:
.byte 0x0
e820table:
.space (32*E820_RECORD_SIZE),0x0 # space for 32 records, each E820_RECORD_SIZE bytes long