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 e820counter
		38	.global e820table
		39	.global e801memorysize
98	cejka	40
		41	.code16
110	jermar	42	.section K_TEXT_START_2
98	cejka	43
95	cejka	44	memmap_arch_init:
139	cejka	45
98	cejka	46	e820begin:
99	jermar	47	xorl %ebx,%ebx # during first call, ebx must be 0
139	cejka	48	movw %bx,%ds
		49	movw %bx,%es
98	cejka	50	movw $e820table,%di
		51	movb $E820_MAX_RECORDS,(e820counter)
		52	e820loop:
139	cejka	53	movl $E820_SMAP,%edx # control sequence "SMAP"
98	cejka	54
139	cejka	55	movl $0x0000e820,%eax # service
98	cejka	56	movl $E820_RECORD_SIZE,%ecx
		57	int $0x15
139	cejka	58	jc e820err
98	cejka	59
99	jermar	60	cmpl $E820_SMAP,%eax # verifying BIOS
139	cejka	61	jne e820err
		62
		63	cmpl $E820_RECORD_SIZE,%ecx
		64	jne e820err # bad record size - bug in bios
98	cejka	65
		66	movw %di,%ax # next record
		67	addw $E820_RECORD_SIZE,%ax
		68	movw %ax,%di
		69
101	cejka	70	decb (e820counter) # buffer is full
		71	jz e820end
98	cejka	72
101	cejka	73	cmpl $0,%ebx
		74	jne e820loop
		75
98	cejka	76	e820end:
139	cejka	77	movb $E820_MAX_RECORDS,%al
		78	subb (e820counter),%al
98	cejka	79	movb %al,(e820counter) # store # of valid entries in e820counter
139	cejka	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
98	cejka	95
139	cejka	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 - its not count by e801 method
		113	movl %edx,(e801memorysize)
		114	e801end:
98	cejka	115	ret
		116
139	cejka	117	#memory size in 1 kb chunks
		118	e801memorysize:
		119	.long 0
98	cejka	120
		121	e820counter:
139	cejka	122	.byte 0xff
		123
98	cejka	124	e820table:
139	cejka	125	.space (32*E820_RECORD_SIZE),0xff # space for 32 records, each E820_RECORD_SIZE bytes long

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(root)/SPARTAN/trunk/arch/ia32/src/boot/memmap.s @ 450 – Rev 139