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#

# Copyright (C) 2001-2004 Jakub Jermar

# 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.

#

## very low and hardware-level functions

#  Mask for interrupts 0 - 31 (bits 0 - 31) where 0 means that int has no error word

# and 1 means interrupt with error word

#define ERROR_WORD_INTERRUPT_LIST 0x00027D00

.text

.global paging_on

.global enable_l_apic_in_msr

.global interrupt_handlers

.global memcpy

.global memsetb

.global memsetw

.global memcmp

## Turn paging on

#

# Enable paging and write-back caching in CR0.

#

paging_on:

	movl %cr0,%edx

	orl $(1<<31),%edx		# paging on

	andl $~((1<<30)|(1<<29)),%edx	# clear Cache Disable and not Write Though

	movl %edx,%cr0

	jmp 0f

0:

	ret

## Enable local APIC

#

# Enable local APIC in MSR.

#

enable_l_apic_in_msr:

	push %eax

	movl $0x1b, %ecx

	rdmsr

	orl $(1<<11),%eax

	orl $(0xfee00000),%eax

	wrmsr

	pop %eax

	ret

## Declare interrupt handlers

#

# Declare interrupt handlers for n interrupt

# vectors starting at vector i.

#

# The handlers setup data segment registers

# and call trap_dispatcher().

#

.macro handler i n

	push %ebp

	movl %esp,%ebp

	pusha

	push %ds

	push %es

	# we must fill the data segment registers

	movw $16,%ax

	movw %ax,%ds

	movw %ax,%es

	movl $(\i),%edi

	pushl %ebp

	addl $4,(%esp)

	pushl %edi

	call trap_dispatcher

	addl $8,%esp

	pop %es

	pop %ds

# CLNT

	pushfl

	pop %eax

	and $0xFFFFBFFF,%eax

	push %eax

	popfl

# Test if this is interrupt with error word or not

	mov $\i,%cl

	movl $1,%eax

	test $0xe0,%cl

	jnz 0f

	and $0x1f,%cl

	shl %cl,%eax

	and $ERROR_WORD_INTERRUPT_LIST,%eax

	jz 0f

# Return with error word

	popa

	pop %ebp

	add $4,%esp	# Skip error word

	iret

0:

# Return with no error word

	popa

	pop %ebp

	iret

	.if (\n-\i)-1

	handler "(\i+1)",\n

	.endif

.endm

# keep in sync with pm.h !!!

IDT_ITEMS=64

interrupt_handlers:

h_start:

	handler 0 64

#	handler 64 128	

#	handler 128 192

#	handler 192 256

h_end:

## Copy memory

#

# Copy a given number of bytes (3rd argument)

# from the memory location defined by 2nd argument

# to the memory location defined by 1st argument.

# The memory areas cannot overlap.

#

SRC=16

DST=12

CNT=20

memcpy:

	push %esi

	push %edi

	movl CNT(%esp),%ecx

	movl DST(%esp),%edi

	movl SRC(%esp),%esi

	rep movsb %ds:(%esi),%es:(%edi)

	pop %edi

	pop %esi

	ret

## Fill memory with bytes

#

# Fill a given number of bytes (2nd argument)

# at memory defined by 1st argument with the

# byte value defined by 3rd argument.

#

DST=12

CNT=16

X=20

memsetb:

	push %eax

	push %edi

	movl CNT(%esp),%ecx

	movl DST(%esp),%edi

	movl X(%esp),%eax

	rep stosb %al,%es:(%edi)

	pop %edi

	pop %eax

	ret

## Fill memory with words

#

# Fill a given number of words (2nd argument)

# at memory defined by 1st argument with the

# word value defined by 3rd argument.

#

DST=12

CNT=16

X=20

memsetw:

	push %eax

	push %edi

	movl CNT(%esp),%ecx

	movl DST(%esp),%edi

	movl X(%esp),%eax

	rep stosw %ax,%es:(%edi)

	pop %edi

	pop %eax

	ret

## Compare memory regions for equality

#

# Compare a given number of bytes (3rd argument)

# at memory locations defined by 1st and 2nd argument

# for equality. If the bytes are equal, EAX contains

# 0.

#

SRC=12

DST=16

CNT=20

memcmp:

	push %esi

	push %edi

	movl CNT(%esp),%ecx

	movl DST(%esp),%edi

	movl SRC(%esp),%esi

	repe cmpsb %es:(%edi),%ds:(%esi)

	movl %ecx,%eax		# %ecx contains the return value (zero on success)

	pop %edi

	pop %esi

	ret

# THIS IS USERSPACE CODE

.global utext

utext:

	xor %ax,%ax

	mov %ax,%ds

	mov %ax,%es

	mov %ax,%fs

	mov %ax,%gs

0:

	int $48

	jmp 0b

	# not reached

utext_end:

.data

.global utext_size

utext_size:

	.long utext_end - utext 

.global interrupt_handler_size

interrupt_handler_size: .long (h_end-h_start)/IDT_ITEMS