WebSVN – HelenOS-historic – Blame – /SPARTAN/trunk/arch/amd64/src/boot/memmap.S

Rev	Author	Line No.	Line
178	palkovsky	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	*/
		28
		29
		30	#include <arch/boot/memmapasm.h>
		31
		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
		37	.global e820counter
		38	.global e820table
		39	.global e801memorysize
		40
		41	.code16
		42	.section K_TEXT_START_2
		43
		44	memmap_arch_init:
		45
		46	e820begin:
		47	xorl %ebx,%ebx # during first call, ebx must be 0
		48	movw %bx,%ds
		49	movw %bx,%es
		50	movw $e820table,%di
		51	movb $E820_MAX_RECORDS,e820counter
		52	e820loop:
		53	movl $E820_SMAP,%edx # control sequence "SMAP"
		54
		55	movl $0x0000e820,%eax # service
		56	movl $E820_RECORD_SIZE,%ecx
		57	int $0x15
		58	jc e820err
		59
		60	cmpl $E820_SMAP,%eax # verifying BIOS
		61	jne e820err
		62
		63	cmpl $E820_RECORD_SIZE,%ecx
		64	jne e820err # bad record size - bug in bios
		65
		66	movw %di,%ax # next record
		67	addw $E820_RECORD_SIZE,%ax
		68	movw %ax,%di
		69
		70	decb e820counter # buffer is full
		71	jz e820end
		72
		73	cmpl $0,%ebx
		74	jne e820loop
		75
		76	e820end:
		77	movb $E820_MAX_RECORDS,%al
		78	subb e820counter,%al
		79	movb %al,e820counter # store # of valid entries in e820counter
		80
		81	jmp e801begin
		82
		83	e820err:
		84	movb $0,e820counter
		85
		86	# method e801 - get size of memory
		87
		88	e801begin:
		89	xorw %dx,%dx
		90	xorw %cx,%cx
		91	xorw %bx,%bx
		92	movw $0xe801,%ax
		93	stc
		94	int $0x15
		95
		96	jc e801end
		97
		98	# fix problem with some BIOSes which use ax:bx rather than cx:dx
		99	testw %cx,%cx
		100	jnz e801cxdx
		101	testw %dx,%dx
		102	jnz e801cxdx
		103
		104	movw %ax,%cx
		105	movw %bx,%dx
		106
		107	e801cxdx:
		108	andl $0xffff,%edx
		109	shll $6,%edx
		110	andl $0xffff,%ecx
		111	addl %ecx,%edx
		112	addl $0x0400,%edx # add lower 1 MB - it's not included by e801 method
		113	movl %edx,e801memorysize
		114	e801end:
		115	ret
		116
		117	#memory size in 1 kb chunks
		118	e801memorysize:
		119	.long 0
		120
		121	e820counter:
219	palkovsky	122	.byte 0x0
178	palkovsky	123
		124	e820table:
219	palkovsky	125	.space (32*E820_RECORD_SIZE),0x0 # space for 32 records, each E820_RECORD_SIZE bytes long

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