DuetPkg/BootSector/st32_64.S

   1 #------------------------------------------------------------------------------
   2 #*
   3 #*   Copyright 2006 - 2007, Intel Corporation
   4 #*   All rights reserved. This program and the accompanying materials
   5 #*   are licensed and made available under the terms and conditions of the BSD License
   6 #*   which accompanies this distribution.  The full text of the license may be found at
   7 #*   http://opensource.org/licenses/bsd-license.php
   8 #*
   9 #*   THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  10 #*   WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  11 #*
  12 #*    st32_64.asm
  13 #*
  14 #*   Abstract:
  15 #*
  16 #------------------------------------------------------------------------------
  17
  18
  19         .stack:
  20         .486p:
  21         .code16
  22
  23 .equ                        FAT_DIRECTORY_ENTRY_SIZE, 0x020
  24 .equ                        FAT_DIRECTORY_ENTRY_SHIFT, 5
  25 .equ                        BLOCK_SIZE, 0x0200
  26 .equ                        BLOCK_MASK, 0x01ff
  27 .equ                        BLOCK_SHIFT, 9
  28
  29        .org 0x0
  30 Ia32Jump:
  31   jmp   BootSectorEntryPoint  # JMP inst    - 3 bytes
  32   nop
  33
  34 OemId:               .ascii  "INTEL   "    # OemId                           - 8 bytes
  35 SectorSize:          .word  0              # Sector Size                     - 2 bytes
  36 SectorsPerCluster:   .byte  0              # Sector Per Cluster              - 1 byte
  37 ReservedSectors:     .word  0              # Reserved Sectors                - 2 bytes
  38 NoFats:              .byte  0              # Number of FATs                  - 1 byte
  39 RootEntries:         .word  0              # Root Entries                    - 2 bytes
  40 Sectors:             .word  0              # Number of Sectors               - 2 bytes
  41 Media:               .byte  0              # Media                           - 1 byte
  42 SectorsPerFat16:     .word  0              # Sectors Per FAT for FAT12/FAT16 - 2 byte
  43 SectorsPerTrack:     .word  0              # Sectors Per Track               - 2 bytes
  44 Heads:               .word  0              # Heads                           - 2 bytes
  45 HiddenSectors:       .long  0              # Hidden Sectors                  - 4 bytes
  46 LargeSectors:        .long  0              # Large Sectors                   - 4 bytes
  47
  48 #******************************************************************************
  49 #
  50 #The structure for FAT32 starting at offset 36 of the boot sector. (At this point,
  51 #the BPB/boot sector for FAT12 and FAT16 differs from the BPB/boot sector for FAT32.)
  52 #
  53 #******************************************************************************
  54
  55 SectorsPerFat32:     .long  0              # Sectors Per FAT for FAT32       - 4 bytes
  56 ExtFlags:            .word  0              # Mirror Flag                     - 2 bytes
  57 FSVersion:           .word  0              # File System Version             - 2 bytes
  58 RootCluster:         .long  0              # 1st Cluster Number of Root Dir  - 4 bytes
  59 FSInfo:              .word  0              # Sector Number of FSINFO         - 2 bytes
  60 BkBootSector:        .word  0              # Sector Number of Bk BootSector  - 2 bytes
  61 Reserved:            .fill 12,1,0          # Reserved Field                  - 12 bytes
  62 PhysicalDrive:       .byte  0              # Physical Drive Number           - 1 byte
  63 Reserved1:           .byte  0              # Reserved Field                  - 1 byte
  64 Signature:           .byte  0              # Extended Boot Signature         - 1 byte
  65 VolId:               .ascii  "    "        # Volume Serial Number            - 4 bytes
  66 FatLabel:            .ascii  "           " # Volume Label                    - 11 bytes
  67 FileSystemType:      .ascii  "FAT32   "    # File System Type                - 8 bytes
  68
  69
  70 BootSectorEntryPoint:
  71       # ASSUME  ds:@code
  72       # ASSUME  ss:@code
  73       # ds = 1000, es = 2000 + x (size of first cluster >> 4)
  74       # cx = Start Cluster of EfiLdr
  75       # dx = Start Cluster of Efivar.bin
  76
  77 # Re use the BPB data stored in Boot Sector
  78         movw    $0x7c00,%bp
  79
  80         pushw   %cx
  81 # Read Efivar.bin
  82 #       1000:dx    = DirectoryEntry of Efivar.bin -> BS.com has filled already
  83         movw    $0x1900,%ax
  84         movw    %ax,%es
  85         testw   %dx,%dx
  86         jnz     CheckVarStoreSize
  87
  88         movb    $1,%al
  89 NoVarStore:
  90         pushw   %es
  91 # Set the 5th byte start @ 0:19000 to non-zero indicating we should init var store header in DxeIpl
  92                                 movb    %al, %es:(4)
  93         jmp     SaveVolumeId
  94
  95 CheckVarStoreSize:
  96         movw    %dx,%di
  97         cmpl    $0x4000, %ds:2(%di)
  98         movb    $2,%al
  99         jne     NoVarStore
 100
 101 LoadVarStore:
 102         movb    $0,%al
 103         movb    %al, %es:(4)
 104         movw    (%di), %cx
 105 #       ES:DI = 1500:0
 106         xorw    %di,%di
 107         pushw   %es
 108         movw    $0x1500,%ax
 109         movw    %ax,%es
 110         call    ReadFile
 111 SaveVolumeId:
 112         popw    %es
 113         movw    VolId(%bp), %ax
 114         movw    %ax, %es:(0)                    # Save Volume Id to 0:19000. we will find the correct volume according to this VolumeId
 115         movw    VolId+2(%bp), %ax
 116         movw    %ax, %es:(2)
 117
 118 # Read Efildr
 119         popw    %cx
 120 #       cx    = Start Cluster of Efildr -> BS.com has filled already
 121 #       ES:DI = 2000:0, first cluster will be read again
 122         xorw    %di,%di                             # di = 0
 123         movw    $0x2000,%ax
 124         movw    %ax,%es
 125         call    ReadFile
 126         movw    %cs,%ax
 127         movw    %ax, %cs:JumpSegment
 128
 129 CheckEm64T:
 130         movl $0x80000001,%eax
 131 #        cpuid
 132         .word 0xA20F
 133         btl  $29,%edx
 134         jc   CheckEm64TPass
 135         pushw %cs
 136         popw %ds
 137         leaw Em64String,%si
 138         movw $18,%cx
 139         jmp  PrintStringAndHalt
 140 CheckEm64TPass:
 141 jumpFarInstruction:
 142         .byte 0xea
 143 jumpOffset:
 144         .word 0x200
 145 jumpSegment:
 146         .word 0x2000
 147
 148
 149
 150 # ****************************************************************************
 151 # ReadFile
 152 #
 153 # Arguments:
 154 #   CX    = Start Cluster of File
 155 #   ES:DI = Buffer to store file content read from disk
 156 #
 157 # Return:
 158 #   (ES << 4 + DI) = end of file content Buffer
 159 #
 160 # ****************************************************************************
 161 ReadFile:
 162 # si      = NumberOfClusters
 163 # cx      = ClusterNumber
 164 # dx      = CachedFatSectorNumber
 165 # ds:0000 = CacheFatSectorBuffer
 166 # es:di   = Buffer to load file
 167 # bx      = NextClusterNumber
 168         pusha
 169         movw    $1,%si                              # NumberOfClusters = 1
 170         pushw   %cx                                 # Push Start Cluster onto stack
 171         movw    $0xfff,%dx                          # CachedFatSectorNumber = 0xfff
 172 FatChainLoop:
 173         movw    %cx,%ax                             # ax = ClusterNumber
 174         andw    $0xfff8,%ax                         # ax = ax & 0xfff8
 175         cmpw    $0xfff8,%ax                         # See if this is the last cluster
 176         je      FoundLastCluster                    # Jump if last cluster found
 177         movw    %cx,%ax                             # ax = ClusterNumber
 178         shlw    $2, %ax                             # FatOffset = ClusterNumber * 2
 179         pushw   %si                                 # Save si
 180         movw    %ax,%si                             # si = FatOffset
 181         shrw    $BLOCK_SHIFT, %ax                   # ax = FatOffset >> BLOCK_SHIFT
 182         addw    ReservedSectors(%bp), %ax           # ax = FatSectorNumber = ReservedSectors + (FatOffset >> BLOCK_OFFSET)
 183         andw    $BLOCK_MASK, %si                    # si = FatOffset & BLOCK_MASK
 184         cmpw    %dx,%ax                             # Compare FatSectorNumber to CachedFatSectorNumber
 185         je      SkipFatRead
 186         movw    $2,%bx
 187         pushw   %es
 188         pushw   %ds
 189         popw    %es
 190         call    ReadBlocks                          # Read 2 blocks starting at AX storing at ES:DI
 191         popw    %es
 192         movw    %ax,%dx                             # CachedFatSectorNumber = FatSectorNumber
 193 SkipFatRead:
 194         movw    (%si), %bx                          # bx = NextClusterNumber
 195         movw    %cx,%ax                             # ax = ClusterNumber
 196         popw    %si                                 # Restore si
 197         decw    %bx                                 # bx = NextClusterNumber - 1
 198         cmpw    %cx,%bx                             # See if (NextClusterNumber-1)==ClusterNumber
 199         jne     ReadClusters
 200         incw    %bx                                 # bx = NextClusterNumber
 201         incw    %si                                 # NumberOfClusters++
 202         movw    %bx,%cx                             # ClusterNumber = NextClusterNumber
 203         jmp     FatChainLoop
 204 ReadClusters:
 205         incw    %bx
 206         popw    %ax                                 # ax = StartCluster
 207         pushw   %bx                                 # StartCluster = NextClusterNumber
 208         movw    %bx,%cx                             # ClusterNumber = NextClusterNumber
 209         subw    $2,%ax                              # ax = StartCluster - 2
 210         xorb    %bh,%bh
 211         movb    SectorsPerCluster(%bp), %bl         # bx = SectorsPerCluster
 212         mulw    %bx                                 # ax = (StartCluster - 2) * SectorsPerCluster
 213         addw    (%bp), %ax                          # ax = FirstClusterLBA + (StartCluster-2)*SectorsPerCluster
 214         pushw   %ax                                 # save start sector
 215         movw    %si,%ax                             # ax = NumberOfClusters
 216         mulw    %bx                                 # ax = NumberOfClusters * SectorsPerCluster
 217         movw    %ax,%bx                             # bx = Number of Sectors
 218         popw    %ax                                 # ax = Start Sector
 219         call    ReadBlocks
 220         movw    $1,%si                              # NumberOfClusters = 1
 221         jmp     FatChainLoop
 222 FoundLastCluster:
 223         popw    %cx
 224         popa
 225         ret
 226
 227
 228 # ****************************************************************************
 229 # ReadBlocks - Reads a set of blocks from a block device
 230 #
 231 # AX    = Start LBA
 232 # BX    = Number of Blocks to Read
 233 # ES:DI = Buffer to store sectors read from disk
 234 # ****************************************************************************
 235
 236 # cx = Blocks
 237 # bx = NumberOfBlocks
 238 # si = StartLBA
 239
 240 ReadBlocks:
 241         pusha
 242         addl    LBAOffsetForBootSector(%bp), %eax   # Add LBAOffsetForBootSector to Start LBA
 243         addl    HiddenSectors(%bp), %eax            # Add HiddenSectors to Start LBA
 244         movl    %eax,%esi                           # esi = Start LBA
 245         movw    %bx,%cx                             # cx = Number of blocks to read
 246 ReadCylinderLoop:
 247         movw    $0x7bfc,%bp                         # bp = 0x7bfc
 248         movl    %esi,%eax                           # eax = Start LBA
 249         xorl    %edx,%edx                           # edx = 0
 250                                 movzwl  (%bp), %ebx                         # bx = MaxSector
 251         divl    %ebx                                # ax = StartLBA / MaxSector
 252         incw    %dx                                 # dx = (StartLBA % MaxSector) + 1
 253
 254         movw    (%bp), %bx                          # bx = MaxSector
 255         subw    %dx,%bx                             # bx = MaxSector - Sector
 256         incw    %bx                                 # bx = MaxSector - Sector + 1
 257         cmpw    %bx,%cx                             # Compare (Blocks) to (MaxSector - Sector + 1)
 258         jg      LimitTransfer
 259         movw    %cx,%bx                             # bx = Blocks
 260 LimitTransfer:
 261         pushw   %ax                                 # save ax
 262         movw    %es,%ax                             # ax = es
 263         shrw    $(BLOCK_SHIFT-4), %ax               # ax = Number of blocks into mem system
 264         andw    $0x7f,%ax                           # ax = Number of blocks into current seg
 265         addw    %bx,%ax                             # ax = End Block number of transfer
 266         cmpw    $0x80,%ax                           # See if it crosses a 64K boundry
 267         jle     NotCrossing64KBoundry               # Branch if not crossing 64K boundry
 268         subw    $0x80,%ax                           # ax = Number of blocks past 64K boundry
 269         subw    %ax,%bx                             # Decrease transfer size by block overage
 270 NotCrossing64KBoundry:
 271         popw    %ax                                 # restore ax
 272
 273         pushw   %cx
 274         movb    %dl,%cl                             # cl = (StartLBA % MaxSector) + 1 = Sector
 275         xorw    %dx,%dx                             # dx = 0
 276         divw    2(%bp)                              # ax = ax / (MaxHead + 1) = Cylinder
 277                                                     # dx = ax % (MaxHead + 1) = Head
 278
 279         pushw   %bx                                 # Save number of blocks to transfer
 280         movb    %dl,%dh                             # dh = Head
 281         movw    $0x7c00,%bp                         # bp = 0x7c00
 282         movb    PhysicalDrive(%bp), %dl             # dl = Drive Number
 283         movb    %al,%ch                             # ch = Cylinder
 284         movb    %bl,%al                             # al = Blocks
 285         movb    $2,%ah                              # ah = Function 2
 286         movw    %di,%bx                             # es:bx = Buffer address
 287         int     $0x13
 288         jc      DiskError
 289         popw    %bx
 290         popw    %cx
 291         movzwl  %bx,%ebx
 292         addl    %ebx,%esi                           # StartLBA = StartLBA + NumberOfBlocks
 293         subw    %bx,%cx                             # Blocks = Blocks - NumberOfBlocks
 294         movw    %es,%ax
 295         shlw    $(BLOCK_SHIFT-4), %bx
 296         addw    %bx,%ax
 297         movw    %ax,%es                             # es:di = es:di + NumberOfBlocks*BLOCK_SIZE
 298         cmpw    $0,%cx
 299         jne     ReadCylinderLoop
 300         popa
 301         ret
 302
 303 DiskError:
 304         pushw %cs
 305         popw %ds
 306         leaw ErrorString,%si
 307         movw $7,%cx
 308         jmp  PrintStringAndHalt
 309
 310 PrintStringAndHalt:
 311         movw $0xb800,%ax
 312         movw %ax,%es
 313         movw $160,%di
 314         rep
 315         movsw
 316 Halt:
 317         jmp   Halt
 318
 319 ErrorString:
 320         .byte 'S', 0x0c, 'E', 0x0c, 'r', 0x0c, 'r', 0x0c, 'o', 0x0c, 'r', 0x0c, '!',0x0c
 321
 322         .org     0x01fa
 323 LBAOffsetForBootSector:
 324         .long 0x0
 325
 326         .org    0x01fe
 327         .word 0xaa55
 328
 329 #******************************************************************************
 330 #******************************************************************************
 331 #******************************************************************************
 332
 333 .equ                 DELAY_PORT, 0x0ed # Port to use for 1uS delay
 334 .equ                 KBD_CONTROL_PORT, 0x060 # 8042 control port
 335 .equ                 KBD_STATUS_PORT, 0x064 # 8042 status port
 336 .equ                 WRITE_DATA_PORT_CMD, 0x0d1 # 8042 command to write the data port
 337 .equ                 ENABLE_A20_CMD, 0x0df # 8042 command to enable A20
 338
 339         .org     0x200
 340         jmp start
 341 Em64String:
 342 .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
 343
 344 start:
 345         movw %cs,%ax
 346         movw %ax,%ds
 347         movw %ax,%es
 348         movw %ax,%ss
 349         movw $MyStack, %sp
 350
 351 #        mov ax,0b800h
 352 #        mov es,ax
 353 #        mov byte ptr es:[160],'a'
 354 #        mov ax,cs
 355 #        mov es,ax
 356
 357         movl $0,%ebx
 358         leal MemoryMap, %edi
 359 MemMapLoop:
 360         movl $0xe820,%eax
 361         movl $20,%ecx
 362         movl $0x534d4150, %edx  # SMAP
 363         int $0x15
 364         jc  MemMapDone
 365         addl $20,%edi
 366         cmpl $0,%ebx
 367         je  MemMapDone
 368         jmp MemMapLoop
 369 MemMapDone:
 370         leal MemoryMap, %eax
 371         subl %eax,%edi                      # Get the address of the memory map
 372                                 movl %edi, MemoryMapSize            # Save the size of the memory map
 373
 374         xorl    %ebx,%ebx
 375         movw    %cs,%bx                     # BX=segment
 376         shll    $4,%ebx                     # BX="linear" address of segment base
 377         leal    GDT_BASE(%ebx), %eax        # EAX=PHYSICAL address of gdt
 378         movl    %eax, (gdtr + 2)            # Put address of gdt into the gdtr
 379         leal    IDT_BASE(%ebx), %eax        # EAX=PHYSICAL address of idt
 380         movl    %eax, (idtr + 2)            # Put address of idt into the idtr
 381         leal    MemoryMapSize(%ebx), %edx   # Physical base address of the memory map
 382
 383 #        mov ax,0b800h
 384 #        mov es,ax
 385 #        mov byte ptr es:[162],'b'
 386 #        mov ax,cs
 387 #        mov es,ax
 388
 389 #
 390 # Enable A20 Gate
 391 #
 392
 393         movw $0x2401,%ax                    # Enable A20 Gate
 394         int $0x15
 395         jnc A20GateEnabled                  # Jump if it suceeded
 396
 397 #
 398 # If INT 15 Function 2401 is not supported, then attempt to Enable A20 manually.
 399 #
 400
 401         call    Empty8042InputBuffer        # Empty the Input Buffer on the 8042 controller
 402         jnz     Timeout8042                 # Jump if the 8042 timed out
 403         outw    %ax, $DELAY_PORT            # Delay 1 uS
 404         movb    $WRITE_DATA_PORT_CMD, %al   # 8042 cmd to write output port
 405         outb    %al, $KBD_STATUS_PORT       # Send command to the 8042
 406         call    Empty8042InputBuffer        # Empty the Input Buffer on the 8042 controller
 407         jnz     Timeout8042                 # Jump if the 8042 timed out
 408         movb    $ENABLE_A20_CMD, %al        # gate address bit 20 on
 409         outb    %al, $KBD_CONTROL_PORT      # Send command to thre 8042
 410         call    Empty8042InputBuffer        # Empty the Input Buffer on the 8042 controller
 411         movw    $25,%cx                     # Delay 25 uS for the command to complete on the 8042
 412 Delay25uS:
 413         outw    %ax, $DELAY_PORT            # Delay 1 uS
 414         loop    Delay25uS
 415 Timeout8042:
 416
 417
 418 A20GateEnabled:
 419
 420 #
 421 # DISABLE INTERRUPTS - Entering Protected Mode
 422 #
 423
 424         cli
 425
 426 #        mov ax,0b800h
 427 #        mov es,ax
 428 #        mov byte ptr es:[164],'c'
 429 #        mov ax,cs
 430 #        mov es,ax
 431
 432     leal OffsetIn32BitProtectedMode, %eax
 433     addl $0x20000+0x6,%eax
 434                 movl %eax, OffsetIn32BitProtectedMode
 435
 436     leal OffsetInLongMode, %eax
 437     addl $0x20000+0x6,%eax
 438     movl %eax, OffsetInLongMode
 439
 440     #
 441     # load GDT
 442     #
 443     .byte 0x66
 444     lgdt    gdtr
 445
 446     #
 447     # Enable Protect Mode (set CR0.PE=1)
 448     #
 449     movl  $cr0, %eax      # Read CR0.
 450     orl   $0x1,%eax       # Set PE=1
 451     movl  %eax, %cr0      # Write CR0.
 452     .byte 0x66
 453     .byte 0xea                        # jmp far 16:32
 454 OffsetIn32BitProtectedMode:
 455     .long 0x0000000                   # offset $+8   (In32BitProtectedMode)
 456     .word 0x10                        # selector  (flat CS)
 457 In32BitProtectedMode:
 458
 459 #
 460 # Entering Long Mode
 461 #
 462     .byte 0x66
 463     movw $8,%ax
 464     movw %ax,%ds
 465     movw %ax,%es
 466     movw %ax,%ss
 467
 468     #
 469     # Enable the 64-bit page-translation-table entries by
 470     # setting CR4.PAE=1 (this is _required_ before activating
 471     # long mode). Paging is not enabled until after long mode
 472     # is enabled.
 473     #
 474     .byte 0xf
 475     .byte 0x20
 476     .byte 0xe0
 477 #    mov eax, cr4
 478     btsl $5,%eax
 479     .byte 0xf
 480     .byte 0x22
 481     .byte 0xe0
 482 #    mov cr4, eax
 483
 484     #
 485     # This is the Trapolean Page Tables that are guarenteed
 486     #  under 4GB.
 487     #
 488     # Address Map:
 489     #    10000 ~    12000 - efildr (loaded)
 490     #    20000 ~    21000 - start64.com
 491     #    21000 ~    22000 - efi64.com
 492     #    22000 ~    90000 - efildr
 493     #    90000 ~    96000 - 4G pagetable (will be reload later)
 494     #
 495     .byte 0xb8
 496     .long 0x90000
 497 #    mov eax, 90000h
 498     movl %eax, %cr3
 499
 500     #
 501     # Enable long mode (set EFER.LME=1).
 502     #
 503     .byte 0xb9
 504     .long 0xc0000080
 505 #    mov   ecx, 0c0000080h ; EFER MSR number.
 506     .byte 0xf
 507     .byte 0x32
 508 #    rdmsr                 ; Read EFER.
 509     .byte 0xf
 510     .byte 0xba
 511     .byte 0xe8
 512     .byte 0x8
 513 #    bts   eax, 8          ; Set LME=1.
 514     .byte 0xf
 515     .byte 0x30
 516 #    wrmsr                 ; Write EFER.
 517
 518     #
 519     # Enable paging to activate long mode (set CR0.PG=1)
 520     #
 521     movl  $cr0, %eax      # Read CR0.
 522     .byte 0xf
 523     .byte 0xba
 524     .byte 0xe8
 525     .byte 0x1f
 526 #    bts   eax, 31         ; Set PG=1.
 527     movl  %eax, %cr0      # Write CR0.
 528     jmp   GoToLongMode
 529 GoToLongMode:
 530
 531     .byte 0x67
 532     .byte 0xea                  # Far Jump $+9:Selector to reload CS
 533 OffsetInLongMode:
 534     .long 00000000              #   $+9 Offset is ensuing instruction boundary
 535     .word 0x38                  #   Selector is our code selector, 38h
 536
 537 InLongMode:
 538     .byte 0x66
 539     movw    $0x30,%ax
 540     movw    %ax,%ds
 541
 542     .byte 0x66
 543     movw    $0x18,%ax
 544     movw    %ax,%es
 545     movw    %ax,%ss
 546     movw    %ax,%ds
 547
 548     .byte 0xbd
 549     .long 0x400000
 550 #    mov ebp,000400000h                  ; Destination of EFILDR32
 551     .byte 0xbb
 552     .long 0x70000
 553 #    mov ebx,000070000h                  ; Length of copy
 554
 555     #
 556     # load idt later
 557     #
 558     .byte 0x48
 559     .byte 0x33
 560     .byte 0xc0
 561 #    xor rax, rax
 562     .byte 0x66
 563      movw $idtr, %ax
 564     .byte 0x48
 565     .byte 0x5
 566     .long 0x20000
 567 #    add rax, 20000h
 568
 569     .byte 0xf
 570     .byte 0x1
 571     .byte 0x18
 572 #    lidt    fword ptr [rax]
 573
 574     .byte 0x48
 575     .byte 0xc7
 576     .byte 0xc0
 577     .long 0x21000
 578 #   mov rax, 21000h
 579     .byte 0x50
 580 #   push rax
 581
 582 # ret
 583     .byte 0xc3
 584
 585 Empty8042InputBuffer:
 586         movw $0,%cx
 587 Empty8042Loop:
 588         outw    %ax, $DELAY_PORT            # Delay 1us
 589         inb     $KBD_STATUS_PORT, %al       # Read the 8042 Status Port
 590         andb    $0x2,%al                    # Check the Input Buffer Full Flag
 591         loopnz  Empty8042Loop               # Loop until the input buffer is empty or a timout of 65536 uS
 592         ret
 593
 594 ##############################################################################
 595 # data
 596 ##############################################################################
 597
 598         .p2align 1
 599
 600                                 gdtr:    .long  GDT_END - GDT_BASE - 1  # GDT limit
 601         .long 0                     # (GDT base gets set above)
 602 ##############################################################################
 603 #   global descriptor table (GDT)
 604 ##############################################################################
 605
 606         .p2align 1
 607
 608 GDT_BASE:
 609 # null descriptor
 610 .equ                NULL_SEL, .-GDT_BASE    # Selector [0x0]
 611         .word 0         # limit 15:0
 612         .word 0         # base 15:0
 613         .byte 0         # base 23:16
 614         .byte 0         # type
 615         .byte 0         # limit 19:16, flags
 616         .byte 0         # base 31:24
 617
 618 # linear data segment descriptor
 619 .equ            LINEAR_SEL, .-GDT_BASE  # Selector [0x8]
 620         .word 0xFFFF    # limit 0xFFFFF
 621         .word 0         # base 0
 622         .byte 0
 623         .byte 0x92      # present, ring 0, data, expand-up, writable
 624         .byte 0xCF              # page-granular, 32-bit
 625         .byte 0
 626
 627 # linear code segment descriptor
 628 .equ            LINEAR_CODE_SEL, .-GDT_BASE # Selector [0x10]
 629         .word 0xFFFF    # limit 0xFFFFF
 630         .word 0         # base 0
 631         .byte 0
 632         .byte 0x9A      # present, ring 0, data, expand-up, writable
 633         .byte 0xCF              # page-granular, 32-bit
 634         .byte 0
 635
 636 # system data segment descriptor
 637 .equ            SYS_DATA_SEL, .-GDT_BASE # Selector [0x18]
 638         .word 0xFFFF    # limit 0xFFFFF
 639         .word 0         # base 0
 640         .byte 0
 641         .byte 0x92      # present, ring 0, data, expand-up, writable
 642         .byte 0xCF              # page-granular, 32-bit
 643         .byte 0
 644
 645 # system code segment descriptor
 646 .equ            SYS_CODE_SEL, .-GDT_BASE # Selector [0x20]
 647         .word 0xFFFF    # limit 0xFFFFF
 648         .word 0         # base 0
 649         .byte 0
 650         .byte 0x9A      # present, ring 0, data, expand-up, writable
 651         .byte 0xCF              # page-granular, 32-bit
 652         .byte 0
 653
 654 # spare segment descriptor
 655 .equ        SPARE3_SEL, .-GDT_BASE  # Selector [0x28]
 656         .word 0         # limit 0xFFFFF
 657         .word 0         # base 0
 658         .byte 0
 659         .byte 0         # present, ring 0, data, expand-up, writable
 660         .byte 0         # page-granular, 32-bit
 661         .byte 0
 662
 663 #
 664 # system data segment descriptor
 665 #
 666 .equ              SYS_DATA64_SEL, .-GDT_BASE # Selector [0x30]
 667         .word 0xFFFF    # limit 0xFFFFF
 668         .word 0         # base 0
 669         .byte 0
 670         .byte 0x92      # P | DPL [1..2] | 1   | 1   | C | R | A
 671         .byte 0xCF      # G | D   | L    | AVL | Segment [19..16]
 672         .byte 0
 673
 674 #
 675 # system code segment descriptor
 676 #
 677 .equ              SYS_CODE64_SEL, .-GDT_BASE # Selector [0x38]
 678         .word 0xFFFF    # limit 0xFFFFF
 679         .word 0         # base 0
 680         .byte 0
 681         .byte 0x9A      # P | DPL [1..2] | 1   | 1   | C | R | A
 682         .byte 0xAF      # G | D   | L    | AVL | Segment [19..16]
 683         .byte 0
 684
 685 # spare segment descriptor
 686 .equ        SPARE4_SEL, .-GDT_BASE    # Selector [0x40]
 687         .word 0         # limit 0xFFFFF
 688         .word 0         # base 0
 689         .byte 0
 690         .byte 0         # present, ring 0, data, expand-up, writable
 691         .byte 0         # page-granular, 32-bit
 692         .byte 0
 693
 694 GDT_END:
 695
 696         .p2align 1
 697
 698
 699
 700 idtr:   .long  IDT_END - IDT_BASE - 1 # IDT limit
 701         .quad 0                     # (IDT base gets set above)
 702
 703 ##############################################################################
 704 #   interrupt descriptor table (IDT)
 705 #
 706 #   Note: The hardware IRQ's specified in this table are the normal PC/AT IRQ
 707 #       mappings.  This implementation only uses the system timer and all other
 708 #       IRQs will remain masked.  The descriptors for vectors 33+ are provided
 709 #       for convenience.
 710 ##############################################################################
 711
 712 #idt_tag db "IDT",0
 713         .p2align 1
 714
 715
 716 IDT_BASE:
 717 # divide by zero (INT 0)
 718 .equ                DIV_ZERO_SEL, .-IDT_BASE
 719         .word 0                           # offset 15:0
 720         .long SYS_CODE64_SEL  # selector 15:0
 721         .byte 0               # 0 for interrupt gate
 722         .byte 0x0e | 0x80     # type = 386 interrupt gate, present
 723         .word 0                           # offset 31:16
 724         .long 0                           # offset 63:32
 725         .long 0                           # 0 for reserved
 726
 727 # debug exception (INT 1)
 728 .equ                DEBUG_EXCEPT_SEL, .-IDT_BASE
 729         .word 0                           # offset 15:0
 730         .long SYS_CODE64_SEL  # selector 15:0
 731         .byte 0               # 0 for interrupt gate
 732         .byte 0x0e | 0x80     # type = 386 interrupt gate, present
 733         .word 0                           # offset 31:16
 734         .long 0                           # offset 63:32
 735         .long 0                           # 0 for reserved
 736
 737 # NMI (INT 2)
 738 .equ                NMI_SEL, .-IDT_BASE
 739         .word 0                           # offset 15:0
 740         .long SYS_CODE64_SEL  # selector 15:0
 741         .byte 0               # 0 for interrupt gate
 742         .byte 0x0e | 0x80     # type = 386 interrupt gate, present
 743         .word 0                           # offset 31:16
 744         .long 0                           # offset 63:32
 745         .long 0                           # 0 for reserved
 746
 747 # soft breakpoint (INT 3)
 748 .equ                BREAKPOINT_SEL, .-IDT_BASE
 749         .word 0                           # offset 15:0
 750         .long SYS_CODE64_SEL  # selector 15:0
 751         .byte 0               # 0 for interrupt gate
 752         .byte 0x0e | 0x80     # type = 386 interrupt gate, present
 753         .word 0                           # offset 31:16
 754         .long 0                           # offset 63:32
 755         .long 0                           # 0 for reserved
 756
 757 # overflow (INT 4)
 758 .equ                OVERFLOW_SEL, .-IDT_BASE
 759         .word 0                           # offset 15:0
 760         .long SYS_CODE64_SEL  # selector 15:0
 761         .byte 0               # 0 for interrupt gate
 762         .byte 0x0e | 0x80     # type = 386 interrupt gate, present
 763         .word 0                           # offset 31:16
 764         .long 0                           # offset 63:32
 765         .long 0                           # 0 for reserved
 766
 767 # bounds check (INT 5)
 768 .equ                BOUNDS_CHECK_SEL, .-IDT_BASE
 769         .word 0                           # offset 15:0
 770         .long SYS_CODE64_SEL  # selector 15:0
 771         .byte 0               # 0 for interrupt gate
 772         .byte 0x0e | 0x80     # type = 386 interrupt gate, present
 773         .word 0                           # offset 31:16
 774         .long 0                           # offset 63:32
 775         .long 0                           # 0 for reserved
 776
 777 # invalid opcode (INT 6)
 778 .equ                INVALID_OPCODE_SEL, .-IDT_BASE
 779         .word 0                           # offset 15:0
 780         .long SYS_CODE64_SEL  # selector 15:0
 781         .byte 0               # 0 for interrupt gate
 782         .byte 0x0e | 0x80     # type = 386 interrupt gate, present
 783         .word 0                           # offset 31:16
 784         .long 0                           # offset 63:32
 785         .long 0                           # 0 for reserved
 786
 787 # device not available (INT 7)
 788 .equ                DEV_NOT_AVAIL_SEL, .-IDT_BASE
 789         .word 0                           # offset 15:0
 790         .long SYS_CODE64_SEL  # selector 15:0
 791         .byte 0               # 0 for interrupt gate
 792         .byte 0x0e | 0x80     # type = 386 interrupt gate, present
 793         .word 0                           # offset 31:16
 794         .long 0                           # offset 63:32
 795         .long 0                           # 0 for reserved
 796
 797 # double fault (INT 8)
 798 .equ                DOUBLE_FAULT_SEL, .-IDT_BASE
 799         .word 0                           # offset 15:0
 800         .long SYS_CODE64_SEL  # selector 15:0
 801         .byte 0               # 0 for interrupt gate
 802         .byte 0x0e | 0x80     # type = 386 interrupt gate, present
 803         .word 0                           # offset 31:16
 804         .long 0                           # offset 63:32
 805         .long 0                           # 0 for reserved
 806
 807 # Coprocessor segment overrun - reserved (INT 9)
 808 .equ                RSVD_INTR_SEL1, .-IDT_BASE
 809         .word 0                           # offset 15:0
 810         .long SYS_CODE64_SEL  # selector 15:0
 811         .byte 0               # 0 for interrupt gate
 812         .byte 0x0e | 0x80     # type = 386 interrupt gate, present
 813         .word 0                           # offset 31:16
 814         .long 0                           # offset 63:32
 815         .long 0                           # 0 for reserved
 816
 817 # invalid TSS (INT 0ah)
 818 .equ                INVALID_TSS_SEL, .-IDT_BASE
 819         .word 0                           # offset 15:0
 820         .long SYS_CODE64_SEL  # selector 15:0
 821         .byte 0               # 0 for interrupt gate
 822         .byte 0x0e | 0x80     # type = 386 interrupt gate, present
 823         .word 0                           # offset 31:16
 824         .long 0                           # offset 63:32
 825         .long 0                           # 0 for reserved
 826
 827 # segment not present (INT 0bh)
 828 .equ                SEG_NOT_PRESENT_SEL, .-IDT_BASE
 829         .word 0                           # offset 15:0
 830         .long SYS_CODE64_SEL  # selector 15:0
 831         .byte 0               # 0 for interrupt gate
 832         .byte 0x0e | 0x80     # type = 386 interrupt gate, present
 833         .word 0                           # offset 31:16
 834         .long 0                           # offset 63:32
 835         .long 0                           # 0 for reserved
 836
 837 # stack fault (INT 0ch)
 838 .equ                STACK_FAULT_SEL, .-IDT_BASE
 839         .word 0                           # offset 15:0
 840         .long SYS_CODE64_SEL  # selector 15:0
 841         .byte 0               # 0 for interrupt gate
 842         .byte 0x0e | 0x80     # type = 386 interrupt gate, present
 843         .word 0                           # offset 31:16
 844         .long 0                           # offset 63:32
 845         .long 0                           # 0 for reserved
 846
 847 # general protection (INT 0dh)
 848 .equ                GP_FAULT_SEL, .-IDT_BASE
 849         .word 0                           # offset 15:0
 850         .long SYS_CODE64_SEL  # selector 15:0
 851         .byte 0               # 0 for interrupt gate
 852         .byte 0x0e | 0x80     # type = 386 interrupt gate, present
 853         .word 0                           # offset 31:16
 854         .long 0                           # offset 63:32
 855         .long 0                           # 0 for reserved
 856
 857 # page fault (INT 0eh)
 858 .equ                PAGE_FAULT_SEL, .-IDT_BASE
 859         .word 0                           # offset 15:0
 860         .long SYS_CODE64_SEL  # selector 15:0
 861         .byte 0               # 0 for interrupt gate
 862         .byte 0x0e | 0x80     # type = 386 interrupt gate, present
 863         .word 0                           # offset 31:16
 864         .long 0                           # offset 63:32
 865         .long 0                           # 0 for reserved
 866
 867 # Intel reserved - do not use (INT 0fh)
 868 .equ                RSVD_INTR_SEL2, .-IDT_BASE
 869         .word 0                           # offset 15:0
 870         .long SYS_CODE64_SEL  # selector 15:0
 871         .byte 0               # 0 for interrupt gate
 872         .byte 0x0e | 0x80     # type = 386 interrupt gate, present
 873         .word 0                           # offset 31:16
 874         .long 0                           # offset 63:32
 875         .long 0                           # 0 for reserved
 876
 877 # floating point error (INT 10h)
 878 .equ                FLT_POINT_ERR_SEL, .-IDT_BASE
 879         .word 0                           # offset 15:0
 880         .long SYS_CODE64_SEL  # selector 15:0
 881         .byte 0               # 0 for interrupt gate
 882         .byte 0x0e | 0x80     # type = 386 interrupt gate, present
 883         .word 0                           # offset 31:16
 884         .long 0                           # offset 63:32
 885         .long 0                           # 0 for reserved
 886
 887 # alignment check (INT 11h)
 888 .equ                ALIGNMENT_CHECK_SEL, .-IDT_BASE
 889         .word 0                           # offset 15:0
 890         .long SYS_CODE64_SEL  # selector 15:0
 891         .byte 0               # 0 for interrupt gate
 892         .byte 0x0e | 0x80     # type = 386 interrupt gate, present
 893         .word 0                           # offset 31:16
 894         .long 0                           # offset 63:32
 895         .long 0                           # 0 for reserved
 896
 897 # machine check (INT 12h)
 898 .equ                MACHINE_CHECK_SEL, .-IDT_BASE
 899         .word 0                           # offset 15:0
 900         .long SYS_CODE64_SEL  # selector 15:0
 901         .byte 0               # 0 for interrupt gate
 902         .byte 0x0e | 0x80     # type = 386 interrupt gate, present
 903         .word 0                           # offset 31:16
 904         .long 0                           # offset 63:32
 905         .long 0                           # 0 for reserved
 906
 907 # SIMD floating-point exception (INT 13h)
 908 .equ                SIMD_EXCEPTION_SEL, .-IDT_BASE
 909         .word 0                           # offset 15:0
 910         .long SYS_CODE64_SEL  # selector 15:0
 911         .byte 0               # 0 for interrupt gate
 912         .byte 0x0e | 0x80     # type = 386 interrupt gate, present
 913         .word 0                           # offset 31:16
 914         .long 0                           # offset 63:32
 915         .long 0                           # 0 for reserved
 916
 917 # 85 unspecified descriptors, First 12 of them are reserved, the rest are avail
 918                                 .fill 85 * 16, 1, 0   # db (85 * 16) dup(0)
 919
 920 # IRQ 0 (System timer) - (INT 68h)
 921 .equ                IRQ0_SEL, .-IDT_BASE
 922         .word 0                           # offset 15:0
 923         .long SYS_CODE64_SEL  # selector 15:0
 924         .byte 0               # 0 for interrupt gate
 925         .byte 0x0e | 0x80     # type = 386 interrupt gate, present
 926         .word 0                           # offset 31:16
 927         .long 0                           # offset 63:32
 928         .long 0                           # 0 for reserved
 929
 930 # IRQ 1 (8042 Keyboard controller) - (INT 69h)
 931 .equ                IRQ1_SEL, .-IDT_BASE
 932         .word 0                           # offset 15:0
 933         .long SYS_CODE64_SEL  # selector 15:0
 934         .byte 0               # 0 for interrupt gate
 935         .byte 0x0e | 0x80     # type = 386 interrupt gate, present
 936         .word 0                           # offset 31:16
 937         .long 0                           # offset 63:32
 938         .long 0                           # 0 for reserved
 939
 940 # Reserved - IRQ 2 redirect (IRQ 2) - DO NOT USE!!! - (INT 6ah)
 941 .equ                IRQ2_SEL, .-IDT_BASE
 942         .word 0                           # offset 15:0
 943         .long SYS_CODE64_SEL  # selector 15:0
 944         .byte 0               # 0 for interrupt gate
 945         .byte 0x0e | 0x80     # type = 386 interrupt gate, present
 946         .word 0                           # offset 31:16
 947         .long 0                           # offset 63:32
 948         .long 0                           # 0 for reserved
 949
 950 # IRQ 3 (COM 2) - (INT 6bh)
 951 .equ                IRQ3_SEL, .-IDT_BASE
 952         .word 0                           # offset 15:0
 953         .long SYS_CODE64_SEL  # selector 15:0
 954         .byte 0               # 0 for interrupt gate
 955         .byte 0x0e | 0x80     # type = 386 interrupt gate, present
 956         .word 0                           # offset 31:16
 957         .long 0                           # offset 63:32
 958         .long 0                           # 0 for reserved
 959
 960 # IRQ 4 (COM 1) - (INT 6ch)
 961 .equ                IRQ4_SEL, .-IDT_BASE
 962         .word 0                           # offset 15:0
 963         .long SYS_CODE64_SEL  # selector 15:0
 964         .byte 0               # 0 for interrupt gate
 965         .byte 0x0e | 0x80     # type = 386 interrupt gate, present
 966         .word 0                           # offset 31:16
 967         .long 0                           # offset 63:32
 968         .long 0                           # 0 for reserved
 969
 970 # IRQ 5 (LPT 2) - (INT 6dh)
 971 .equ                IRQ5_SEL, .-IDT_BASE
 972         .word 0                           # offset 15:0
 973         .long SYS_CODE64_SEL  # selector 15:0
 974         .byte 0               # 0 for interrupt gate
 975         .byte 0x0e | 0x80     # type = 386 interrupt gate, present
 976         .word 0                           # offset 31:16
 977         .long 0                           # offset 63:32
 978         .long 0                           # 0 for reserved
 979
 980 # IRQ 6 (Floppy controller) - (INT 6eh)
 981 .equ                IRQ6_SEL, .-IDT_BASE
 982         .word 0                           # offset 15:0
 983         .long SYS_CODE64_SEL  # selector 15:0
 984         .byte 0               # 0 for interrupt gate
 985         .byte 0x0e | 0x80     # type = 386 interrupt gate, present
 986         .word 0                           # offset 31:16
 987         .long 0                           # offset 63:32
 988         .long 0                           # 0 for reserved
 989
 990 # IRQ 7 (LPT 1) - (INT 6fh)
 991 .equ                IRQ7_SEL, .-IDT_BASE
 992         .word 0                           # offset 15:0
 993         .long SYS_CODE64_SEL  # selector 15:0
 994         .byte 0               # 0 for interrupt gate
 995         .byte 0x0e | 0x80     # type = 386 interrupt gate, present
 996         .word 0                           # offset 31:16
 997         .long 0                           # offset 63:32
 998         .long 0                           # 0 for reserved
 999
1000 # IRQ 8 (RTC Alarm) - (INT 70h)
1001 .equ                IRQ8_SEL, .-IDT_BASE
1002         .word 0                           # offset 15:0
1003         .long SYS_CODE64_SEL  # selector 15:0
1004         .byte 0               # 0 for interrupt gate
1005         .byte 0x0e | 0x80     # type = 386 interrupt gate, present
1006         .word 0                           # offset 31:16
1007         .long 0                           # offset 63:32
1008         .long 0                           # 0 for reserved
1009
1010 # IRQ 9 - (INT 71h)
1011 .equ                IRQ9_SEL, .-IDT_BASE
1012         .word 0                           # offset 15:0
1013         .long SYS_CODE64_SEL  # selector 15:0
1014         .byte 0               # 0 for interrupt gate
1015         .byte 0x0e | 0x80     # type = 386 interrupt gate, present
1016         .word 0                           # offset 31:16
1017         .long 0                           # offset 63:32
1018         .long 0                           # 0 for reserved
1019
1020 # IRQ 10 - (INT 72h)
1021 .equ                 IRQ10_SEL, .-IDT_BASE
1022         .word 0                           # offset 15:0
1023         .long SYS_CODE64_SEL  # selector 15:0
1024         .byte 0               # 0 for interrupt gate
1025         .byte 0x0e | 0x80     # type = 386 interrupt gate, present
1026         .word 0                           # offset 31:16
1027         .long 0                           # offset 63:32
1028         .long 0                           # 0 for reserved
1029
1030 # IRQ 11 - (INT 73h)
1031 .equ                 IRQ11_SEL, .-IDT_BASE
1032         .word 0                           # offset 15:0
1033         .long SYS_CODE64_SEL  # selector 15:0
1034         .byte 0               # 0 for interrupt gate
1035         .byte 0x0e | 0x80     # type = 386 interrupt gate, present
1036         .word 0                           # offset 31:16
1037         .long 0                           # offset 63:32
1038         .long 0                           # 0 for reserved
1039
1040 # IRQ 12 (PS/2 mouse) - (INT 74h)
1041 .equ                 IRQ12_SEL, .-IDT_BASE
1042         .word 0                           # offset 15:0
1043         .long SYS_CODE64_SEL  # selector 15:0
1044         .byte 0               # 0 for interrupt gate
1045         .byte 0x0e | 0x80     # type = 386 interrupt gate, present
1046         .word 0                           # offset 31:16
1047         .long 0                           # offset 63:32
1048         .long 0                           # 0 for reserved
1049
1050 # IRQ 13 (Floating point error) - (INT 75h)
1051 .equ                 IRQ13_SEL, .-IDT_BASE
1052         .word 0                           # offset 15:0
1053         .long SYS_CODE64_SEL  # selector 15:0
1054         .byte 0               # 0 for interrupt gate
1055         .byte 0x0e | 0x80     # type = 386 interrupt gate, present
1056         .word 0                           # offset 31:16
1057         .long 0                           # offset 63:32
1058         .long 0                           # 0 for reserved
1059
1060 # IRQ 14 (Secondary IDE) - (INT 76h)
1061 .equ                 IRQ14_SEL, .-IDT_BASE
1062         .word 0                           # offset 15:0
1063         .long SYS_CODE64_SEL  # selector 15:0
1064         .byte 0               # 0 for interrupt gate
1065         .byte 0x0e | 0x80     # type = 386 interrupt gate, present
1066         .word 0                           # offset 31:16
1067         .long 0                           # offset 63:32
1068         .long 0                           # 0 for reserved
1069
1070 # IRQ 15 (Primary IDE) - (INT 77h)
1071 .equ                 IRQ15_SEL, .-IDT_BASE
1072         .word 0                           # offset 15:0
1073         .long SYS_CODE64_SEL  # selector 15:0
1074         .byte 0               # 0 for interrupt gate
1075         .byte 0x0e | 0x80     # type = 386 interrupt gate, present
1076         .word 0                           # offset 31:16
1077         .long 0                           # offset 63:32
1078         .long 0                           # 0 for reserved
1079
1080 IDT_END:
1081
1082         .p2align 1
1083
1084 MemoryMapSize:  .long 0
1085 MemoryMap:  .long 0,0,0,0,0,0,0,0
1086         .long 0,0,0,0,0,0,0,0
1087         .long 0,0,0,0,0,0,0,0
1088         .long 0,0,0,0,0,0,0,0
1089         .long 0,0,0,0,0,0,0,0
1090         .long 0,0,0,0,0,0,0,0
1091         .long 0,0,0,0,0,0,0,0
1092         .long 0,0,0,0,0,0,0,0
1093         .long 0,0,0,0,0,0,0,0
1094         .long 0,0,0,0,0,0,0,0
1095         .long 0,0,0,0,0,0,0,0
1096         .long 0,0,0,0,0,0,0,0
1097         .long 0,0,0,0,0,0,0,0
1098         .long 0,0,0,0,0,0,0,0
1099         .long 0,0,0,0,0,0,0,0
1100         .long 0,0,0,0,0,0,0,0
1101         .long 0,0,0,0,0,0,0,0
1102         .long 0,0,0,0,0,0,0,0
1103         .long 0,0,0,0,0,0,0,0
1104         .long 0,0,0,0,0,0,0,0
1105         .long 0,0,0,0,0,0,0,0
1106         .long 0,0,0,0,0,0,0,0
1107         .long 0,0,0,0,0,0,0,0
1108         .long 0,0,0,0,0,0,0,0
1109         .long 0,0,0,0,0,0,0,0
1110         .long 0,0,0,0,0,0,0,0
1111         .long 0,0,0,0,0,0,0,0
1112         .long 0,0,0,0,0,0,0,0
1113         .long 0,0,0,0,0,0,0,0
1114         .long 0,0,0,0,0,0,0,0
1115
1116         .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
1117         .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
1118
1119                                 #.org 0x0fe0  #Just for pass build
1120 MyStack:
1121         # below is the pieces of the IVT that is used to redirect INT 68h - 6fh
1122         #    back to INT 08h - 0fh  when in real mode...  It is 'org'ed to a
1123         #    known low address (20f00) so it can be set up by PlMapIrqToVect in
1124         #    8259.c
1125
1126         int $8
1127         iret
1128
1129         int $9
1130         iret
1131
1132         int $10
1133         iret
1134
1135         int $11
1136         iret
1137
1138         int $12
1139         iret
1140
1141         int $13
1142         iret
1143
1144         int $14
1145         iret
1146
1147         int $15
1148         iret
1149
1150
1151                                 #.org 0x0ffe #Just for pass build
1152 BlockSignature:
1153         .word 0xaa55
1154