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_RECORD_SIZE = MEMMAP_E820_RECORD_SIZE
		33	E820_MAX_RECORDS = MEMMAP_E820_MAX_RECORDS
		34	E820_SMAP = 0x534d4150
		35
		36	.global memmap_arch_init
139	cejka	37	.global e801memorysize
98	cejka	38
		39	.code16
110	jermar	40	.section K_TEXT_START_2
98	cejka	41
95	cejka	42	memmap_arch_init:
139	cejka	43
98	cejka	44	e820begin:
99	jermar	45	xorl %ebx,%ebx # during first call, ebx must be 0
139	cejka	46	movw %bx,%ds
		47	movw %bx,%es
243	palkovsky	48	movw $e820table_boot,%di
		49	movb $E820_MAX_RECORDS,e820counter_boot
98	cejka	50	e820loop:
139	cejka	51	movl $E820_SMAP,%edx # control sequence "SMAP"
98	cejka	52
139	cejka	53	movl $0x0000e820,%eax # service
98	cejka	54	movl $E820_RECORD_SIZE,%ecx
		55	int $0x15
139	cejka	56	jc e820err
98	cejka	57
99	jermar	58	cmpl $E820_SMAP,%eax # verifying BIOS
139	cejka	59	jne e820err
		60
		61	cmpl $E820_RECORD_SIZE,%ecx
		62	jne e820err # bad record size - bug in bios
98	cejka	63
		64	movw %di,%ax # next record
		65	addw $E820_RECORD_SIZE,%ax
		66	movw %ax,%di
		67
243	palkovsky	68	decb e820counter_boot # buffer is full
101	cejka	69	jz e820end
98	cejka	70
101	cejka	71	cmpl $0,%ebx
		72	jne e820loop
		73
98	cejka	74	e820end:
139	cejka	75	movb $E820_MAX_RECORDS,%al
243	palkovsky	76	subb e820counter_boot,%al
		77	movb %al,e820counter_boot # store # of valid entries in e820counter
139	cejka	78
		79	jmp e801begin
		80
		81	e820err:
243	palkovsky	82	movb $0,e820counter_boot
139	cejka	83
		84	# method e801 - get size of memory
		85
		86	e801begin:
		87	xorw %dx,%dx
		88	xorw %cx,%cx
		89	xorw %bx,%bx
		90	movw $0xe801,%ax
		91	stc
		92	int $0x15
98	cejka	93
139	cejka	94	jc e801end
		95
		96	# fix problem with some BIOSes which use ax:bx rather than cx:dx
		97	testw %cx,%cx
		98	jnz e801cxdx
		99	testw %dx,%dx
		100	jnz e801cxdx
		101
		102	movw %ax,%cx
		103	movw %bx,%dx
		104
		105	e801cxdx:
		106	andl $0xffff,%edx
		107	shll $6,%edx
		108	andl $0xffff,%ecx
		109	addl %ecx,%edx
149	jermar	110	addl $0x0400,%edx # add lower 1 MB - it's not included by e801 method
		111	movl %edx,e801memorysize
139	cejka	112	e801end:
98	cejka	113	ret
		114
139	cejka	115	#memory size in 1 kb chunks
		116	e801memorysize:
		117	.long 0
243	palkovsky	118

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(root)/SPARTAN/trunk/arch/ia32/src/boot/memmap.s @ 450 – Rev 243