source: mainline/arch/ia32/src/asm.S@ 74b2f5bf

#
# 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 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:


## 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