#------------------------------------------------------------------------------
#*
#* Copyright (c) 2006 - 2011, Intel Corporation. All rights reserved.<BR>
#* This program and the accompanying materials
#* are licensed and made available under the terms and conditions of the BSD License
#* which accompanies this distribution. The full text of the license may be found at
#* http://opensource.org/licenses/bsd-license.php
#*
#* THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
#* WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
#*
#* start16.asm
#*
#* Abstract:
#*
#------------------------------------------------------------------------------
#.MODEL small
.stack:
.486p:
.code16
.equ FAT_DIRECTORY_ENTRY_SIZE, 0x0020
.equ FAT_DIRECTORY_ENTRY_SHIFT, 5
.equ BLOCK_SIZE, 0x0200
.equ BLOCK_MASK, 0x01ff
.equ BLOCK_SHIFT, 9
.org 0x00
.global _start
_start:
Ia32Jump:
jmp BootSectorEntryPoint # JMP inst - 3 bytes
nop
OemId: .ascii "INTEL " # OemId - 8 bytes
SectorSize: .word 0 # Sector Size - 16 bits
SectorsPerCluster: .byte 0 # Sector Per Cluster - 8 bits
ReservedSectors: .word 0 # Reserved Sectors - 16 bits
NoFats: .byte 0 # Number of FATs - 8 bits
RootEntries: .word 0 # Root Entries - 16 bits
Sectors: .word 0 # Number of Sectors - 16 bits
Media: .byte 0 # Media - 8 bits - ignored
SectorsPerFat: .word 0 # Sectors Per FAT - 16 bits
SectorsPerTrack: .word 0 # Sectors Per Track - 16 bits - ignored
Heads: .word 0 # Heads - 16 bits - ignored
HiddenSectors: .long 0 # Hidden Sectors - 32 bits - ignored
LargeSectors: .long 0 # Large Sectors - 32 bits
PhysicalDrive: .byte 0 # PhysicalDriveNumber - 8 bits - ignored
CurrentHead: .byte 0 # Current Head - 8 bits
Signature: .byte 0 # Signature - 8 bits - ignored
VolId: .ascii " " # Volume Serial Number- 4 bytes
FatLabel: .ascii " " # Label - 11 bytes
SystemId: .ascii "FAT16 " # SystemId - 8 bytes
BootSectorEntryPoint:
#ASSUME ds:@code
#ASSUME ss:@code
# ds = 1000, es = 2000 + x (size of first cluster >> 4)
# cx = Start Cluster of EfiLdr
# dx = Start Cluster of Efivar.bin
# Re use the BPB data stored in Boot Sector
movw $0x7c00, %bp
pushw %cx
# Read Efivar.bin
# 1000:dx = DirectoryEntry of Efivar.bin -> BS.com has filled already
movw $0x1900, %ax
movw %ax, %es
testw %dx, %dx
jnz CheckVarStoreSize
movb $1, %al
NoVarStore:
pushw %es
# Set the 5th byte start @ 0:19000 to non-zero indicating we should init var store header in DxeIpl
movb %al, %es:4
jmp SaveVolumeId
CheckVarStoreSize:
movw %dx, %di
cmpl $0x4000, %ds:2(%di)
movb $2, %al
jne NoVarStore
LoadVarStore:
movb $0, %al
movb %al, %es:4
movw (%di), %cx
# ES:DI = 1500:0
xorw %di, %di
pushw %es
movw $0x1500, %ax
movw %ax, %es
call ReadFile
SaveVolumeId:
popw %es
movw VolId(%bp), %ax
movw %ax, %es:0 # Save Volume Id to 0:19000. we will find the correct volume according to this VolumeId
movw VolId+2(%bp), %ax
movw %ax, %es:2
# Read Efildr
popw %cx
# cx = Start Cluster of Efildr -> BS.com has filled already
# ES:DI = 2000:0, first cluster will be read again
xorw %di, %di # di = 0
movw $0x2000, %ax
movw %ax, %es
call ReadFile
movw %cs, %ax
movw %ax, %cs:JumpSegment
JumpFarInstruction:
.byte 0xea
JumpOffset:
.word 0x200
JumpSegment:
.word 0x2000
# ****************************************************************************
# ReadFile
#
# Arguments:
# CX = Start Cluster of File
# ES:DI = Buffer to store file content read from disk
#
# Return:
# (ES << 4 + DI) = end of file content Buffer
#
# ****************************************************************************
ReadFile:
# si = NumberOfClusters
# cx = ClusterNumber
# dx = CachedFatSectorNumber
# ds:0000 = CacheFatSectorBuffer
# es:di = Buffer to load file
# bx = NextClusterNumber
pusha
movw $1, %si # NumberOfClusters = 1
pushw %cx # Push Start Cluster onto stack
movw $0xfff, %dx # CachedFatSectorNumber = 0xfff
FatChainLoop:
movw %cx, %ax # ax = ClusterNumber
andw $0xfff8, %ax # ax = ax & 0xfff8
cmpw $0xfff8, %ax # See if this is the last cluster
je FoundLastCluster # Jump if last cluster found
movw %cx, %ax # ax = ClusterNumber
shlw %ax # FatOffset = ClusterNumber * 2
pushw %si # Save si
movw %ax, %si # si = FatOffset
shrw $BLOCK_SHIFT, %ax # ax = FatOffset >> BLOCK_SHIFT
addw ReservedSectors(%bp), %ax # ax = FatSectorNumber = ReservedSectors + (FatOffset >> BLOCK_OFFSET)
andw $BLOCK_MASK, %si # si = FatOffset & BLOCK_MASK
cmpw %dx, %ax # Compare FatSectorNumber to CachedFatSectorNumber
je SkipFatRead
movw $2, %bx
pushw %es
pushw %ds
popw %es
call ReadBlocks # Read 2 blocks starting at AX storing at ES:DI
popw %es
movw %ax, %dx # CachedFatSectorNumber = FatSectorNumber
SkipFatRead:
movw (%si), %bx # bx = NextClusterNumber
movw %cx, %ax # ax = ClusterNumber
popw %si # Restore si
decw %bx # bx = NextClusterNumber - 1
cmpw %cx, %bx # See if (NextClusterNumber-1)==ClusterNumber
jne ReadClusters
incw %bx # bx = NextClusterNumber
incw %si # NumberOfClusters++
movw %bx, %cx # ClusterNumber = NextClusterNumber
jmp FatChainLoop
ReadClusters:
incw %bx
popw %ax # ax = StartCluster
pushw %bx # StartCluster = NextClusterNumber
movw %bx, %cx # ClusterNumber = NextClusterNumber
subw $2, %ax # ax = StartCluster - 2
xorb %bh, %bh
movb SectorsPerCluster(%bp), %bl # bx = SectorsPerCluster
mulw %bx # ax = (StartCluster - 2) * SectorsPerCluster
addw (%bp), %ax # ax = FirstClusterLBA + (StartCluster-2)*SectorsPerCluster
pushw %ax # save start sector
movw %si, %ax # ax = NumberOfClusters
mulw %bx # ax = NumberOfClusters * SectorsPerCluster
movw %ax, %bx # bx = Number of Sectors
popw %ax # ax = Start Sector
call ReadBlocks
movw $1, %si # NumberOfClusters = 1
jmp FatChainLoop
FoundLastCluster:
popw %cx
popa
ret
# ****************************************************************************
# ReadBlocks - Reads a set of blocks from a block device
#
# AX = Start LBA
# BX = Number of Blocks to Read
# ES:DI = Buffer to store sectors read from disk
# ****************************************************************************
# cx = Blocks
# bx = NumberOfBlocks
# si = StartLBA
ReadBlocks:
pusha
addl LBAOffsetForBootSector(%bp), %eax # Add LBAOffsetForBootSector to Start LBA
addl HiddenSectors(%bp), %eax # Add HiddenSectors to Start LBA
movl %eax, %esi # esi = Start LBA
movw %bx, %cx # cx = Number of blocks to read
ReadCylinderLoop:
movw $0x7bfc, %bp # bp = 0x7bfc
movl %esi, %eax # eax = Start LBA
xorl %edx, %edx # edx = 0
movzwl (%bp), %ebx # bx = MaxSector
divl %ebx # ax = StartLBA / MaxSector
incw %dx # dx = (StartLBA % MaxSector) + 1
movw (%bp), %bx # bx = MaxSector
subw %dx, %bx # bx = MaxSector - Sector
incw %bx # bx = MaxSector - Sector + 1
cmpw %bx, %cx # Compare (Blocks) to (MaxSector - Sector + 1)
jg LimitTransfer
movw %cx, %bx # bx = Blocks
LimitTransfer:
pushw %ax # save ax
movw %es, %ax # ax = es
shrw $(BLOCK_SHIFT-4), %ax # ax = Number of blocks into mem system
andw $0x7f, %ax # ax = Number of blocks into current seg
addw %bx, %ax # ax = End Block number of transfer
cmpw $0x80, %ax # See if it crosses a 64K boundry
jle NotCrossing64KBoundry # Branch if not crossing 64K boundry
subw $0x80, %ax # ax = Number of blocks past 64K boundry
subw %ax, %bx # Decrease transfer size by block overage
NotCrossing64KBoundry:
popw %ax # restore ax
pushw %cx
movb %dl, %cl # cl = (StartLBA % MaxSector) + 1 = Sector
xorw %dx, %dx # dx = 0
divw 2(%bp) # ax = ax / (MaxHead + 1) = Cylinder
# dx = ax % (MaxHead + 1) = Head
pushw %bx # Save number of blocks to transfer
movb %dl, %dh # dh = Head
movw $0x7c00, %bp # bp = 0x7c00
movb PhysicalDrive(%bp), %dl # dl = Drive Number
movb %al, %ch # ch = Cylinder
movb %bl, %al # al = Blocks
movb $2, %ah # ah = Function 2
movw %di, %bx # es:bx = Buffer address
int $0x13
jc DiskError
popw %bx
popw %cx
movzwl %bx, %ebx
addl %ebx, %esi # StartLBA = StartLBA + NumberOfBlocks
subw %bx, %cx # Blocks = Blocks - NumberOfBlocks
movw %es, %ax
shlw $(BLOCK_SHIFT-4), %bx
addw %bx, %ax
movw %ax, %es # es:di = es:di + NumberOfBlocks*BLOCK_SIZE
cmpw $0, %cx
jne ReadCylinderLoop
popa
ret
DiskError:
pushw %cs
popw %ds
leaw ErrorString, %si
movw $7, %cx
jmp PrintStringAndHalt
PrintStringAndHalt:
movw $0xb800, %ax
movw %ax, %es
movw $160, %di
rep
movsw
Halt:
jmp Halt
ErrorString:
.byte 'S', 0x0c, 'E', 0x0c, 'r', 0x0c, 'r', 0x0c, 'o', 0x0c, 'r', 0x0c, '!', 0x0c
# .org 0x01fa # Just for passing build.
LBAOffsetForBootSector:
.long 0x0
# .org 0x01fe # Just for passing build.
.word 0xaa55
#******************************************************************************
#******************************************************************************
#******************************************************************************
.equ DELAY_PORT, 0x0ed # Port to use for 1uS delay
.equ KBD_CONTROL_PORT, 0x060 # 8042 control port
.equ KBD_STATUS_PORT, 0x064 # 8042 status port
.equ WRITE_DATA_PORT_CMD, 0x0d1 # 8042 command to write the data port
.equ ENABLE_A20_CMD, 0x0df # 8042 command to enable A20
# .org 0x0200 # Just for passing build.
jmp start
Em64String:
.byte 'E', 0x0c, 'm', 0x0c, '6', 0x0c, '4', 0x0c, 'T', 0x0c, ' ', 0x0c, 'U', 0x0c, 'n', 0x0c, 's', 0x0c, 'u', 0x0c, 'p', 0x0c, 'p', 0x0c, 'o', 0x0c, 'r', 0x0c, 't', 0x0c, 'e', 0x0c, 'd', 0x0c, '!', 0x0c
start:
movw %cs, %ax
movw %ax, %ds
movw %ax, %es
movw %ax, %ss
movw $MyStack, %sp
# mov ax,0b800h
# mov es,ax
# mov byte ptr es:[160],'a'
# mov ax,cs
# mov es,ax
movl $0, %ebx
leal MemoryMap, %edi
MemMapLoop:
movl $0xe820, %eax
movl $20, %ecx
movl $0x534d4150, %edx # 0x534d4150 stands for 'SMAP'
int $0x15
jc MemMapDone
addl $20, %edi
cmpl $0, %ebx
je MemMapDone
jmp MemMapLoop
MemMapDone:
leal MemoryMap, %eax
subl %eax, %edi # Get the address of the memory map
movl %edi, MemoryMapSize # Save the size of the memory map
xorl %ebx, %ebx
movw %cs, %bx # BX=segment
shll $4, %ebx # BX="linear" address of segment base
leal GDT_BASE(%ebx), %eax # EAX=PHYSICAL address of gdt
movl %eax, gdtr + 2 # Put address of gdt into the gdtr
leal IDT_BASE(%ebx), %eax # EAX=PHYSICAL address of idt
movl %eax, idtr + 2 # Put address of idt into the idtr
leal MemoryMapSize(%ebx), %edx # Physical base address of the memory map
addl $0x1000, %ebx # Source of EFI32
movl %ebx, JUMP+2
addl $0x1000, %ebx
movl %ebx, %esi # Source of EFILDR32
# mov ax,0b800h
# mov es,ax
# mov byte ptr es:[162],'b'
# mov ax,cs
# mov es,ax
#
# Enable A20 Gate
#
movw $0x2401, %ax # Enable A20 Gate
int $0x15
jnc A20GateEnabled # Jump if it suceeded
#
# If INT 15 Function 2401 is not supported, then attempt to Enable A20 manually.
#
call Empty8042InputBuffer # Empty the Input Buffer on the 8042 controller
jnz Timeout8042 # Jump if the 8042 timed out
outw %ax, $DELAY_PORT # Delay 1 uS
movb $WRITE_DATA_PORT_CMD, %al # 8042 cmd to write output port
outb %al, $KBD_STATUS_PORT # Send command to the 8042
call Empty8042InputBuffer # Empty the Input Buffer on the 8042 controller
jnz Timeout8042 # Jump if the 8042 timed out
movb $ENABLE_A20_CMD, %al # gate address bit 20 on
outb %al, $KBD_CONTROL_PORT # Send command to thre 8042
call Empty8042InputBuffer # Empty the Input Buffer on the 8042 controller
movw $25, %cx # Delay 25 uS for the command to complete on the 8042
Delay25uS:
outw %ax, $DELAY_PORT # Delay 1 uS
loop Delay25uS
Timeout8042:
A20GateEnabled:
movw $0x0008, %bx # Flat data descriptor
#
# DISABLE INTERRUPTS - Entering Protected Mode
#
cli
# mov ax,0b800h
# mov es,ax
# mov byte ptr es:[164],'c'
# mov ax,cs
# mov es,ax
.byte 0x66
lgdt gdtr
.byte 0x66
lidt idtr
movl %cr0, %eax
orb $1, %al
movl %eax, %cr0
JUMP:
# jmp far 0010:00020000
.byte 0x66
.byte 0xea
.long 0x00020000
.word 0x0010
Empty8042InputBuffer:
movw $0, %cx
Empty8042Loop:
outw %ax, $DELAY_PORT # Delay 1us
inb $KBD_STATUS_PORT, %al # Read the 8042 Status Port
andb $0x2, %al # Check the Input Buffer Full Flag
loopnz Empty8042Loop # Loop until the input buffer is empty or a timout of 65536 uS
ret
##############################################################################
# data
##############################################################################
.p2align 1
gdtr: .word GDT_END - GDT_BASE - 1 # GDT limit
.long 0 # (GDT base gets set above)
##############################################################################
# global descriptor table (GDT)
##############################################################################
.p2align 1
GDT_BASE:
# null descriptor
.equ NULL_SEL, .-GDT_BASE
.word 0 # limit 15:0
.word 0 # base 15:0
.byte 0 # base 23:16
.byte 0 # type
.byte 0 # limit 19:16, flags
.byte 0 # base 31:24
# linear data segment descriptor
.equ LINEAR_SEL, .-GDT_BASE
.word 0xFFFF # limit 0xFFFFF
.word 0 # base 0
.byte 0
.byte 0x92 # present, ring 0, data, expand-up, writable
.byte 0xCF # page-granular, 32-bit
.byte 0
# linear code segment descriptor
.equ LINEAR_CODE_SEL, .-GDT_BASE
.word 0xFFFF # limit 0xFFFFF
.word 0 # base 0
.byte 0
.byte 0x9A # present, ring 0, data, expand-up, writable
.byte 0xCF # page-granular, 32-bit
.byte 0
# system data segment descriptor
.equ SYS_DATA_SEL, .-GDT_BASE
.word 0xFFFF # limit 0xFFFFF
.word 0 # base 0
.byte 0
.byte 0x92 # present, ring 0, data, expand-up, writable
.byte 0xCF # page-granular, 32-bit
.byte 0
# system code segment descriptor
.equ SYS_CODE_SEL, .-GDT_BASE
.word 0xFFFF # limit 0xFFFFF
.word 0 # base 0
.byte 0
.byte 0x9A # present, ring 0, data, expand-up, writable
.byte 0xCF # page-granular, 32-bit
.byte 0
# spare segment descriptor
.equ SPARE3_SEL, .-GDT_BASE
.word 0 # limit 0xFFFFF
.word 0 # base 0
.byte 0
.byte 0 # present, ring 0, data, expand-up, writable
.byte 0 # page-granular, 32-bit
.byte 0
# spare segment descriptor
.equ SPARE4_SEL, .-GDT_BASE
.word 0 # limit 0xFFFFF
.word 0 # base 0
.byte 0
.byte 0 # present, ring 0, data, expand-up, writable
.byte 0 # page-granular, 32-bit
.byte 0
# spare segment descriptor
.equ SPARE5_SEL, .-GDT_BASE
.word 0 # limit 0xFFFFF
.word 0 # base 0
.byte 0
.byte 0 # present, ring 0, data, expand-up, writable
.byte 0 # page-granular, 32-bit
.byte 0
GDT_END:
.p2align 1
idtr: .word IDT_END - IDT_BASE - 1 # IDT limit
.long 0 # (IDT base gets set above)
##############################################################################
# interrupt descriptor table (IDT)
#
# Note: The hardware IRQ's specified in this table are the normal PC/AT IRQ
# mappings. This implementation only uses the system timer and all other
# IRQs will remain masked. The descriptors for vectors 33+ are provided
# for convenience.
##############################################################################
#idt_tag db "IDT",0
.p2align 1
IDT_BASE:
# divide by zero (INT 0)
.equ DIV_ZERO_SEL, .-IDT_BASE
.word 0 # offset 15:0
.word SYS_CODE_SEL # selector 15:0
.byte 0 # 0 for interrupt gate
.byte 0x0e | 0x80 # (10001110)type = 386 interrupt gate, present
.word 0 # offset 31:16
# debug exception (INT 1)
.equ DEBUG_EXCEPT_SEL, .-IDT_BASE
.word 0 # offset 15:0
.word SYS_CODE_SEL # selector 15:0
.byte 0 # 0 for interrupt gate
.byte 0x0e | 0x80 # (10001110)type = 386 interrupt gate, present
.word 0 # offset 31:16
# NMI (INT 2)
.equ NMI_SEL, .-IDT_BASE
.word 0 # offset 15:0
.word SYS_CODE_SEL # selector 15:0
.byte 0 # 0 for interrupt gate
.byte 0x0e | 0x80 # (10001110)type = 386 interrupt gate, present
.word 0 # offset 31:16
# soft breakpoint (INT 3)
.equ BREAKPOINT_SEL, .-IDT_BASE
.word 0 # offset 15:0
.word SYS_CODE_SEL # selector 15:0
.byte 0 # 0 for interrupt gate
.byte 0x0e | 0x80 # (10001110)type = 386 interrupt gate, present
.word 0 # offset 31:16
# overflow (INT 4)
.equ OVERFLOW_SEL, .-IDT_BASE
.word 0 # offset 15:0
.word SYS_CODE_SEL # selector 15:0
.byte 0 # 0 for interrupt gate
.byte 0x0e | 0x80 # (10001110)type = 386 interrupt gate, present
.word 0 # offset 31:16
# bounds check (INT 5)
.equ BOUNDS_CHECK_SEL, .-IDT_BASE
.word 0 # offset 15:0
.word SYS_CODE_SEL # selector 15:0
.byte 0 # 0 for interrupt gate
.byte 0x0e | 0x80 # (10001110)type = 386 interrupt gate, present
.word 0 # offset 31:16
# invalid opcode (INT 6)
.equ INVALID_OPCODE_SEL, .-IDT_BASE
.word 0 # offset 15:0
.word SYS_CODE_SEL # selector 15:0
.byte 0 # 0 for interrupt gate
.byte 0x0e | 0x80 # (10001110)type = 386 interrupt gate, present
.word 0 # offset 31:16
# device not available (INT 7)
.equ DEV_NOT_AVAIL_SEL, .-IDT_BASE
.word 0 # offset 15:0
.word SYS_CODE_SEL # selector 15:0
.byte 0 # 0 for interrupt gate
.byte 0x0e | 0x80 # (10001110)type = 386 interrupt gate, present
.word 0 # offset 31:16
# double fault (INT 8)
.equ DOUBLE_FAULT_SEL, .-IDT_BASE
.word 0 # offset 15:0
.word SYS_CODE_SEL # selector 15:0
.byte 0 # 0 for interrupt gate
.byte 0x0e | 0x80 # (10001110)type = 386 interrupt gate, present
.word 0 # offset 31:16
# Coprocessor segment overrun - reserved (INT 9)
.equ RSVD_INTR_SEL1, .-IDT_BASE
.word 0 # offset 15:0
.word SYS_CODE_SEL # selector 15:0
.byte 0 # 0 for interrupt gate
.byte 0x0e | 0x80 # (10001110)type = 386 interrupt gate, present
.word 0 # offset 31:16
# invalid TSS (INT 0ah)
.equ INVALID_TSS_SEL, .-IDT_BASE
.word 0 # offset 15:0
.word SYS_CODE_SEL # selector 15:0
.byte 0 # 0 for interrupt gate
.byte 0x0e | 0x80 # (10001110)type = 386 interrupt gate, present
.word 0 # offset 31:16
# segment not present (INT 0bh)
.equ SEG_NOT_PRESENT_SEL, .-IDT_BASE
.word 0 # offset 15:0
.word SYS_CODE_SEL # selector 15:0
.byte 0 # 0 for interrupt gate
.byte 0x0e | 0x80 # (10001110)type = 386 interrupt gate, present
.word 0 # offset 31:16
# stack fault (INT 0ch)
.equ STACK_FAULT_SEL, .-IDT_BASE
.word 0 # offset 15:0
.word SYS_CODE_SEL # selector 15:0
.byte 0 # 0 for interrupt gate
.byte 0x0e | 0x80 # (10001110)type = 386 interrupt gate, present
.word 0 # offset 31:16
# general protection (INT 0dh)
.equ GP_FAULT_SEL, .-IDT_BASE
.word 0 # offset 15:0
.word SYS_CODE_SEL # selector 15:0
.byte 0 # 0 for interrupt gate
.byte 0x0e | 0x80 # (10001110)type = 386 interrupt gate, present
.word 0 # offset 31:16
# page fault (INT 0eh)
.equ PAGE_FAULT_SEL, .-IDT_BASE
.word 0 # offset 15:0
.word SYS_CODE_SEL # selector 15:0
.byte 0 # 0 for interrupt gate
.byte 0x0e | 0x80 # (10001110)type = 386 interrupt gate, present
.word 0 # offset 31:16
# Intel reserved - do not use (INT 0fh)
.equ RSVD_INTR_SEL2, .-IDT_BASE
.word 0 # offset 15:0
.word SYS_CODE_SEL # selector 15:0
.byte 0 # 0 for interrupt gate
.byte 0x0e | 0x80 # (10001110)type = 386 interrupt gate, present
.word 0 # offset 31:16
# floating point error (INT 10h)
.equ FLT_POINT_ERR_SEL, .-IDT_BASE
.word 0 # offset 15:0
.word SYS_CODE_SEL # selector 15:0
.byte 0 # 0 for interrupt gate
.byte 0x0e | 0x80 # (10001110)type = 386 interrupt gate, present
.word 0 # offset 31:16
# alignment check (INT 11h)
.equ ALIGNMENT_CHECK_SEL, .-IDT_BASE
.word 0 # offset 15:0
.word SYS_CODE_SEL # selector 15:0
.byte 0 # 0 for interrupt gate
.byte 0x0e | 0x80 # (10001110)type = 386 interrupt gate, present
.word 0 # offset 31:16
# machine check (INT 12h)
.equ MACHINE_CHECK_SEL, .-IDT_BASE
.word 0 # offset 15:0
.word SYS_CODE_SEL # selector 15:0
.byte 0 # 0 for interrupt gate
.byte 0x0e | 0x80 # (10001110)type = 386 interrupt gate, present
.word 0 # offset 31:16
# SIMD floating-point exception (INT 13h)
.equ SIMD_EXCEPTION_SEL, .-IDT_BASE
.word 0 # offset 15:0
.word SYS_CODE_SEL # selector 15:0
.byte 0 # 0 for interrupt gate
.byte 0x0e | 0x80 # (10001110)type = 386 interrupt gate, present
.word 0 # offset 31:16
# 85 unspecified descriptors, First 12 of them are reserved, the rest are avail
.fill 85 * 8, 1, 0
# IRQ 0 (System timer) - (INT 68h)
.equ IRQ0_SEL, .-IDT_BASE
.word 0 # offset 15:0
.word SYS_CODE_SEL # selector 15:0
.byte 0 # 0 for interrupt gate
.byte 0x0e | 0x80 # (10001110)type = 386 interrupt gate, present
.word 0 # offset 31:16
# IRQ 1 (8042 Keyboard controller) - (INT 69h)
.equ IRQ1_SEL, .-IDT_BASE
.word 0 # offset 15:0
.word SYS_CODE_SEL # selector 15:0
.byte 0 # 0 for interrupt gate
.byte 0x0e | 0x80 # (10001110)type = 386 interrupt gate, present
.word 0 # offset 31:16
# Reserved - IRQ 2 redirect (IRQ 2) - DO NOT USE!!! - (INT 6ah)
.equ IRQ2_SEL, .-IDT_BASE
.word 0 # offset 15:0
.word SYS_CODE_SEL # selector 15:0
.byte 0 # 0 for interrupt gate
.byte 0x0e | 0x80 # (10001110)type = 386 interrupt gate, present
.word 0 # offset 31:16
# IRQ 3 (COM 2) - (INT 6bh)
.equ IRQ3_SEL, .-IDT_BASE
.word 0 # offset 15:0
.word SYS_CODE_SEL # selector 15:0
.byte 0 # 0 for interrupt gate
.byte 0x0e | 0x80 # (10001110)type = 386 interrupt gate, present
.word 0 # offset 31:16
# IRQ 4 (COM 1) - (INT 6ch)
.equ IRQ4_SEL, .-IDT_BASE
.word 0 # offset 15:0
.word SYS_CODE_SEL # selector 15:0
.byte 0 # 0 for interrupt gate
.byte 0x0e | 0x80 # (10001110)type = 386 interrupt gate, present
.word 0 # offset 31:16
# IRQ 5 (LPT 2) - (INT 6dh)
.equ IRQ5_SEL, .-IDT_BASE
.word 0 # offset 15:0
.word SYS_CODE_SEL # selector 15:0
.byte 0 # 0 for interrupt gate
.byte 0x0e | 0x80 # (10001110)type = 386 interrupt gate, present
.word 0 # offset 31:16
# IRQ 6 (Floppy controller) - (INT 6eh)
.equ IRQ6_SEL, .-IDT_BASE
.word 0 # offset 15:0
.word SYS_CODE_SEL # selector 15:0
.byte 0 # 0 for interrupt gate
.byte 0x0e | 0x80 # (10001110)type = 386 interrupt gate, present
.word 0 # offset 31:16
# IRQ 7 (LPT 1) - (INT 6fh)
.equ IRQ7_SEL, .-IDT_BASE
.word 0 # offset 15:0
.word SYS_CODE_SEL # selector 15:0
.byte 0 # 0 for interrupt gate
.byte 0x0e | 0x80 # (10001110)type = 386 interrupt gate, present
.word 0 # offset 31:16
# IRQ 8 (RTC Alarm) - (INT 70h)
.equ IRQ8_SEL, .-IDT_BASE
.word 0 # offset 15:0
.word SYS_CODE_SEL # selector 15:0
.byte 0 # 0 for interrupt gate
.byte 0x0e | 0x80 # (10001110)type = 386 interrupt gate, present
.word 0 # offset 31:16
# IRQ 9 - (INT 71h)
.equ IRQ9_SEL, .-IDT_BASE
.word 0 # offset 15:0
.word SYS_CODE_SEL # selector 15:0
.byte 0 # 0 for interrupt gate
.byte 0x0e | 0x80 # (10001110)type = 386 interrupt gate, present
.word 0 # offset 31:16
# IRQ 10 - (INT 72h)
.equ IRQ10_SEL, .-IDT_BASE
.word 0 # offset 15:0
.word SYS_CODE_SEL # selector 15:0
.byte 0 # 0 for interrupt gate
.byte 0x0e | 0x80 # (10001110)type = 386 interrupt gate, present
.word 0 # offset 31:16
# IRQ 11 - (INT 73h)
.equ IRQ11_SEL, .-IDT_BASE
.word 0 # offset 15:0
.word SYS_CODE_SEL # selector 15:0
.byte 0 # 0 for interrupt gate
.byte 0x0e | 0x80 # (10001110)type = 386 interrupt gate, present
.word 0 # offset 31:16
# IRQ 12 (PS/2 mouse) - (INT 74h)
.equ IRQ12_SEL, .-IDT_BASE
.word 0 # offset 15:0
.word SYS_CODE_SEL # selector 15:0
.byte 0 # 0 for interrupt gate
.byte 0x0e | 0x80 # (10001110)type = 386 interrupt gate, present
.word 0 # offset 31:16
# IRQ 13 (Floating point error) - (INT 75h)
.equ IRQ13_SEL, .-IDT_BASE
.word 0 # offset 15:0
.word SYS_CODE_SEL # selector 15:0
.byte 0 # 0 for interrupt gate
.byte 0x0e | 0x80 # (10001110)type = 386 interrupt gate, present
.word 0 # offset 31:16
# IRQ 14 (Secondary IDE) - (INT 76h)
.equ IRQ14_SEL, .-IDT_BASE
.word 0 # offset 15:0
.word SYS_CODE_SEL # selector 15:0
.byte 0 # 0 for interrupt gate
.byte 0x0e | 0x80 # (10001110)type = 386 interrupt gate, present
.word 0 # offset 31:16
# IRQ 15 (Primary IDE) - (INT 77h)
.equ IRQ15_SEL, .-IDT_BASE
.word 0 # offset 15:0
.word SYS_CODE_SEL # selector 15:0
.byte 0 # 0 for interrupt gate
.byte 0x0e | 0x80 # (10001110)type = 386 interrupt gate, present
.word 0 # offset 31:16
IDT_END:
.p2align 1
MemoryMapSize: .long 0
MemoryMap: .long 0,0,0,0,0,0,0,0
.long 0,0,0,0,0,0,0,0
.long 0,0,0,0,0,0,0,0
.long 0,0,0,0,0,0,0,0
.long 0,0,0,0,0,0,0,0
.long 0,0,0,0,0,0,0,0
.long 0,0,0,0,0,0,0,0
.long 0,0,0,0,0,0,0,0
.long 0,0,0,0,0,0,0,0
.long 0,0,0,0,0,0,0,0
.long 0,0,0,0,0,0,0,0
.long 0,0,0,0,0,0,0,0
.long 0,0,0,0,0,0,0,0
.long 0,0,0,0,0,0,0,0
.long 0,0,0,0,0,0,0,0
.long 0,0,0,0,0,0,0,0
.long 0,0,0,0,0,0,0,0
.long 0,0,0,0,0,0,0,0
.long 0,0,0,0,0,0,0,0
.long 0,0,0,0,0,0,0,0
.long 0,0,0,0,0,0,0,0
.long 0,0,0,0,0,0,0,0
.long 0,0,0,0,0,0,0,0
.long 0,0,0,0,0,0,0,0
.long 0,0,0,0,0,0,0,0
.long 0,0,0,0,0,0,0,0
.long 0,0,0,0,0,0,0,0
.long 0,0,0,0,0,0,0,0
.long 0,0,0,0,0,0,0,0
.long 0,0,0,0,0,0,0,0
.long 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
.long 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
.org 0x0fe0
MyStack:
# below is the pieces of the IVT that is used to redirect INT 68h - 6fh
# back to INT 08h - 0fh when in real mode... It is 'org'ed to a
# known low address (20f00) so it can be set up by PlMapIrqToVect in
# 8259.c
int $8
iret
int $9
iret
int $10
iret
int $11
iret
int $12
iret
int $13
iret
int $14
iret
int $15
iret
.org 0x0ffe
BlockSignature:
.word 0xaa55