WebSVN – HelenOS – Blame – /SPARTAN/trunk/arch/ia32/src/boot/memmap.s

Rev	Author	Line No.	Line
98	cejka	1	/*
		2	* Copyright (C) 2005 Josef Cejka
		3	* All rights reserved.
		4	*
		5	* Redistribution and use in source and binary forms, with or without
		6	* modification, are permitted provided that the following conditions
		7	* are met:
		8	*
		9	* - Redistributions of source code must retain the above copyright
		10	* notice, this list of conditions and the following disclaimer.
		11	* - Redistributions in binary form must reproduce the above copyright
		12	* notice, this list of conditions and the following disclaimer in the
		13	* documentation and/or other materials provided with the distribution.
		14	* - The name of the author may not be used to endorse or promote products
		15	* derived from this software without specific prior written permission.
		16	*
		17	* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
		18	* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
		19	* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
		20	* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
		21	* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
		22	* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
		23	* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
		24	* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
		25	* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
		26	* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
		27	*/
95	cejka	28
		29
139	cejka	30	#include <arch/boot/memmapasm.h>
95	cejka	31
98	cejka	32	E820_SMAP = 0x534d4150
		33
		34	.global memmap_arch_init
139	cejka	35	.global e801memorysize
98	cejka	36
		37	.code16
110	jermar	38	.section K_TEXT_START_2
98	cejka	39
95	cejka	40	memmap_arch_init:
139	cejka	41
98	cejka	42	e820begin:
99	jermar	43	xorl %ebx,%ebx # during first call, ebx must be 0
139	cejka	44	movw %bx,%ds
		45	movw %bx,%es
243	palkovsky	46	movw $e820table_boot,%di
285	decky	47	movb $MEMMAP_E820_MAX_RECORDS,e820counter_boot
98	cejka	48	e820loop:
139	cejka	49	movl $E820_SMAP,%edx # control sequence "SMAP"
98	cejka	50
139	cejka	51	movl $0x0000e820,%eax # service
285	decky	52	movl $MEMMAP_E820_RECORD_SIZE,%ecx
98	cejka	53	int $0x15
139	cejka	54	jc e820err
98	cejka	55
99	jermar	56	cmpl $E820_SMAP,%eax # verifying BIOS
139	cejka	57	jne e820err
		58
285	decky	59	cmpl $MEMMAP_E820_RECORD_SIZE,%ecx
139	cejka	60	jne e820err # bad record size - bug in bios
98	cejka	61
		62	movw %di,%ax # next record
285	decky	63	addw $MEMMAP_E820_RECORD_SIZE,%ax
98	cejka	64	movw %ax,%di
		65
243	palkovsky	66	decb e820counter_boot # buffer is full
101	cejka	67	jz e820end
98	cejka	68
101	cejka	69	cmpl $0,%ebx
		70	jne e820loop
		71
98	cejka	72	e820end:
285	decky	73	movb $MEMMAP_E820_MAX_RECORDS,%al
243	palkovsky	74	subb e820counter_boot,%al
		75	movb %al,e820counter_boot # store # of valid entries in e820counter
139	cejka	76
		77	jmp e801begin
		78
		79	e820err:
243	palkovsky	80	movb $0,e820counter_boot
139	cejka	81
		82	# method e801 - get size of memory
		83
		84	e801begin:
		85	xorw %dx,%dx
		86	xorw %cx,%cx
		87	xorw %bx,%bx
		88	movw $0xe801,%ax
		89	stc
		90	int $0x15
98	cejka	91
139	cejka	92	jc e801end
		93
		94	# fix problem with some BIOSes which use ax:bx rather than cx:dx
		95	testw %cx,%cx
		96	jnz e801cxdx
		97	testw %dx,%dx
		98	jnz e801cxdx
		99
		100	movw %ax,%cx
		101	movw %bx,%dx
		102
		103	e801cxdx:
		104	andl $0xffff,%edx
		105	shll $6,%edx
		106	andl $0xffff,%ecx
		107	addl %ecx,%edx
149	jermar	108	addl $0x0400,%edx # add lower 1 MB - it's not included by e801 method
		109	movl %edx,e801memorysize
139	cejka	110	e801end:
98	cejka	111	ret
		112
139	cejka	113	#memory size in 1 kb chunks
		114	e801memorysize:
		115	.long 0
264	cejka	116

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(root)/SPARTAN/trunk/arch/ia32/src/boot/memmap.s @ 450 – Rev 285