DuetPkg/BootSector/start32.S

   1 #------------------------------------------------------------------------------
   2 #*
   3 #*   Copyright (c) 2006 - 2011, Intel Corporation. All rights reserved.<BR>
   4 #*   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 #*    start32.asm
  13 #*
  14 #*   Abstract:
  15 #*
  16 #------------------------------------------------------------------------------
  17
  18         #.MODEL small
  19         .stack:
  20         .486p:
  21         .code:
  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
  31 .global _start
  32 _start:
  33
  34 Ia32Jump:
  35   jmp   BootSectorEntryPoint  # JMP inst    - 3 bytes
  36   nop
  37
  38 OemId:               .ascii  "INTEL   "    # OemId                           - 8 bytes
  39 SectorSize:          .word  0              # Sector Size                     - 2 bytes
  40 SectorsPerCluster:   .byte  0              # Sector Per Cluster              - 1 byte
  41 ReservedSectors:     .word  0              # Reserved Sectors                - 2 bytes
  42 NoFats:              .byte  0              # Number of FATs                  - 1 byte
  43 RootEntries:         .word  0              # Root Entries                    - 2 bytes
  44 Sectors:             .word  0              # Number of Sectors               - 2 bytes
  45 Media:               .byte  0              # Media                           - 1 byte
  46 SectorsPerFat16:     .word  0              # Sectors Per FAT for FAT12/FAT16 - 2 byte
  47 SectorsPerTrack:     .word  0              # Sectors Per Track               - 2 bytes
  48 Heads:               .word  0              # Heads                           - 2 bytes
  49 HiddenSectors:       .long  0              # Hidden Sectors                  - 4 bytes
  50 LargeSectors:        .long  0              # Large Sectors                   - 4 bytes
  51
  52 #******************************************************************************
  53 #
  54 #The structure for FAT32 starting at offset 36 of the boot sector. (At this point,
  55 #the BPB/boot sector for FAT12 and FAT16 differs from the BPB/boot sector for FAT32.)
  56 #
  57 #******************************************************************************
  58
  59 SectorsPerFat32:     .long  0              # Sectors Per FAT for FAT32       - 4 bytes
  60 ExtFlags:            .word  0              # Mirror Flag                     - 2 bytes
  61 FSVersion:           .word  0              # File System Version             - 2 bytes
  62 RootCluster:         .long  0              # 1st Cluster Number of Root Dir  - 4 bytes
  63 FSInfo:              .word  0              # Sector Number of FSINFO         - 2 bytes
  64 BkBootSector:        .word  0              # Sector Number of Bk BootSector  - 2 bytes
  65 Reserved:            .fill 12,1,0          # Reserved Field                  - 12 bytes
  66 PhysicalDrive:       .byte  0              # Physical Drive Number           - 1 byte
  67 Reserved1:           .byte  0              # Reserved Field                  - 1 byte
  68 Signature:           .byte  0              # Extended Boot Signature         - 1 byte
  69 VolId:               .ascii  "    "        # Volume Serial Number            - 4 bytes
  70 FatLabel:            .ascii  "           " # Volume Label                    - 11 bytes
  71 FileSystemType:      .ascii  "FAT32   "    # File System Type                - 8 bytes
  72
  73 BootSectorEntryPoint:
  74         #ASSUME ds:@code
  75         #ASSUME ss:@code
  76       # ds = 1000, es = 2000 + x (size of first cluster >> 4)
  77       # cx = Start Cluster of EfiLdr
  78       # dx = Start Cluster of Efivar.bin
  79
  80 # Re use the BPB data stored in Boot Sector
  81         movw    $0x7c00, %bp
  82
  83
  84         pushw   %cx
  85 # Read Efivar.bin
  86 #       1000:dx    = DirectoryEntry of Efivar.bin -> BS.com has filled already
  87         movw    $0x1900, %ax
  88         movw    %ax, %es
  89         testw   %dx, %dx
  90         jnz     CheckVarStoreSize
  91
  92         movb    $1, %al
  93 NoVarStore:
  94         pushw   %es
  95 # Set the 5th byte start @ 0:19000 to non-zero indicating we should init var store header in DxeIpl
  96         movb    %al, %es:4
  97         jmp     SaveVolumeId
  98
  99 CheckVarStoreSize:
 100         movw    %dx, %di
 101         cmpl    $0x4000, %ds:2(%di)
 102         movb    $2, %al
 103         jne     NoVarStore
 104
 105 LoadVarStore:
 106         movb    $0, %al
 107         movb    %al, %es:4
 108         movw    (%di), %cx
 109 #       ES:DI = 1500:0
 110         xorw    %di, %di
 111         pushw   %es
 112         movw    $0x1500, %ax
 113         movw    %ax, %es
 114         call    ReadFile
 115 SaveVolumeId:
 116         popw    %es
 117         movw    VolId(%bp), %ax
 118         movw    %ax, %es:0                       # Save Volume Id to 0:19000. we will find the correct volume according to this VolumeId
 119         movw    VolId+2(%bp), %ax
 120         movw    %ax, %es:2
 121
 122 # Read Efildr
 123         popw    %cx
 124 #       cx    = Start Cluster of Efildr -> BS.com has filled already
 125 #       ES:DI = 2000:0, first cluster will be read again
 126         xorw    %di, %di                            # di = 0
 127         movw    $0x2000, %ax
 128         movw    %ax, %es
 129         call    ReadFile
 130         movw    %cs, %ax
 131         movw    %ax, %cs:JumpSegment
 132 JumpFarInstruction:
 133         .byte   0xea
 134 JumpOffset:
 135         .word   0x200
 136 JumpSegment:
 137         .word   0x2000
 138
 139
 140
 141
 142 # ****************************************************************************
 143 # ReadFile
 144 #
 145 # Arguments:
 146 #   CX    = Start Cluster of File
 147 #   ES:DI = Buffer to store file content read from disk
 148 #
 149 # Return:
 150 #   (ES << 4 + DI) = end of file content Buffer
 151 #
 152 # ****************************************************************************
 153 ReadFile:
 154 # si      = NumberOfClusters
 155 # cx      = ClusterNumber
 156 # dx      = CachedFatSectorNumber
 157 # ds:0000 = CacheFatSectorBuffer
 158 # es:di   = Buffer to load file
 159 # bx      = NextClusterNumber
 160         pusha
 161         movw    $1, %si                             # NumberOfClusters = 1
 162         pushw   %cx                                 # Push Start Cluster onto stack
 163         movw    $0xfff, %dx                         # CachedFatSectorNumber = 0xfff
 164 FatChainLoop:
 165         movw    %cx, %ax                            # ax = ClusterNumber
 166         andw    $0xfff8, %ax                        # ax = ax & 0xfff8
 167         cmpw    $0xfff8, %ax                        # See if this is the last cluster
 168         je      FoundLastCluster                    # Jump if last cluster found
 169         movw    %cx, %ax                            # ax = ClusterNumber
 170         shlw    $2, %ax                             # FatOffset = ClusterNumber * 4
 171         pushw   %si                                 # Save si
 172         movw    %ax, %si                            # si = FatOffset
 173         shrw    $BLOCK_SHIFT, %ax                   # ax = FatOffset >> BLOCK_SHIFT
 174         addw    ReservedSectors(%bp), %ax           # ax = FatSectorNumber = ReservedSectors + (FatOffset >> BLOCK_OFFSET)
 175         andw    $BLOCK_MASK, %si                    # si = FatOffset & BLOCK_MASK
 176         cmpw    %dx, %ax                            # Compare FatSectorNumber to CachedFatSectorNumber
 177         je      SkipFatRead
 178         movw    $2, %bx
 179         pushw   %es
 180         pushw   %ds
 181         popw    %es
 182         call    ReadBlocks                          # Read 2 blocks starting at AX storing at ES:DI
 183         popw    %es
 184         movw    %ax, %dx                            # CachedFatSectorNumber = FatSectorNumber
 185 SkipFatRead:
 186         movw    (%si), %bx                          # bx = NextClusterNumber
 187         movw    %cx, %ax                            # ax = ClusterNumber
 188         popw    %si                                 # Restore si
 189         decw    %bx                                 # bx = NextClusterNumber - 1
 190         cmpw    %cx, %bx                            # See if (NextClusterNumber-1)==ClusterNumber
 191         jne     ReadClusters
 192         incw    %bx                                 # bx = NextClusterNumber
 193         incw    %si                                 # NumberOfClusters++
 194         movw    %bx, %cx                            # ClusterNumber = NextClusterNumber
 195         jmp     FatChainLoop
 196 ReadClusters:
 197         incw    %bx
 198         popw    %ax                                 # ax = StartCluster
 199         pushw   %bx                                 # StartCluster = NextClusterNumber
 200         movw    %bx, %cx                            # ClusterNumber = NextClusterNumber
 201         subw    $2, %ax                             # ax = StartCluster - 2
 202         xorb    %bh, %bh
 203         movb    SectorsPerCluster(%bp), %bl         # bx = SectorsPerCluster
 204         mulw    %bx                                 # ax = (StartCluster - 2) * SectorsPerCluster
 205         addw    (%bp), %ax                          # ax = FirstClusterLBA + (StartCluster-2)*SectorsPerCluster
 206         pushw   %ax                                 # save start sector
 207         movw    %si, %ax                            # ax = NumberOfClusters
 208         mulw    %bx                                 # ax = NumberOfClusters * SectorsPerCluster
 209         movw    %ax, %bx                            # bx = Number of Sectors
 210         popw    %ax                                 # ax = Start Sector
 211         call    ReadBlocks
 212         movw    $1, %si                             # NumberOfClusters = 1
 213         jmp     FatChainLoop
 214 FoundLastCluster:
 215         popw    %cx
 216         popa
 217         ret
 218
 219
 220 # ****************************************************************************
 221 # ReadBlocks - Reads a set of blocks from a block device
 222 #
 223 # AX    = Start LBA
 224 # BX    = Number of Blocks to Read
 225 # ES:DI = Buffer to store sectors read from disk
 226 # ****************************************************************************
 227
 228 # cx = Blocks
 229 # bx = NumberOfBlocks
 230 # si = StartLBA
 231
 232 ReadBlocks:
 233         pusha
 234         addl    LBAOffsetForBootSector(%bp), %eax            # Add LBAOffsetForBootSector to Start LBA
 235         addl    HiddenSectors(%bp), %eax            # Add HiddenSectors to Start LBA
 236         movl    %eax, %esi                          # esi = Start LBA
 237         movw    %bx, %cx                            # cx = Number of blocks to read
 238 ReadCylinderLoop:
 239         movw    $0x7bfc, %bp                        # bp = 0x7bfc
 240         movl    %esi, %eax                          # eax = Start LBA
 241         xorl    %edx, %edx                          # edx = 0
 242         movzwl  (%bp), %ebx                         # bx = MaxSector
 243         divl    %ebx                                # ax = StartLBA / MaxSector
 244         incw    %dx                                 # dx = (StartLBA % MaxSector) + 1
 245
 246         movw    (%bp), %bx                          # bx = MaxSector
 247         subw    %dx, %bx                            # bx = MaxSector - Sector
 248         incw    %bx                                 # bx = MaxSector - Sector + 1
 249         cmpw    %bx, %cx                            # Compare (Blocks) to (MaxSector - Sector + 1)
 250         jg      LimitTransfer
 251         movw    %cx, %bx                            # bx = Blocks
 252 LimitTransfer:
 253         pushw   %ax                                 # save ax
 254         movw    %es, %ax                            # ax = es
 255         shrw    $(BLOCK_SHIFT-4), %ax                # ax = Number of blocks into mem system
 256         andw    $0x7f, %ax                          # ax = Number of blocks into current seg
 257         addw    %bx, %ax                            # ax = End Block number of transfer
 258         cmpw    $0x80, %ax                          # See if it crosses a 64K boundry
 259         jle     NotCrossing64KBoundry               # Branch if not crossing 64K boundry
 260         subw    $0x80, %ax                          # ax = Number of blocks past 64K boundry
 261         subw    %ax, %bx                            # Decrease transfer size by block overage
 262 NotCrossing64KBoundry:
 263         popw    %ax                                 # restore ax
 264
 265         pushw   %cx
 266         movb    %dl, %cl                            # cl = (StartLBA % MaxSector) + 1 = Sector
 267         xorw    %dx, %dx                            # dx = 0
 268         divw    2(%bp)                              # ax = ax / (MaxHead + 1) = Cylinder
 269                                                     # dx = ax % (MaxHead + 1) = Head
 270
 271         pushw   %bx                                 # Save number of blocks to transfer
 272         movb    %dl, %dh                            # dh = Head
 273         movw    $0x7c00, %bp                        # bp = 0x7c00
 274         movb    PhysicalDrive(%bp), %dl             # dl = Drive Number
 275         movb    %al, %ch                            # ch = Cylinder
 276         movb    %bl, %al                            # al = Blocks
 277         movb    $2, %ah                             # ah = Function 2
 278         movw    %di, %bx                            # es:bx = Buffer address
 279         int     $0x13
 280         jc      DiskError
 281         popw    %bx
 282         popw    %cx
 283         movzwl  %bx, %ebx
 284         addl    %ebx, %esi                          # StartLBA = StartLBA + NumberOfBlocks
 285         subw    %bx, %cx                            # Blocks = Blocks - NumberOfBlocks
 286         movw    %es, %ax
 287         shlw    $(BLOCK_SHIFT-4), %bx
 288         addw    %bx, %ax
 289         movw    %ax, %es                            # es:di = es:di + NumberOfBlocks*BLOCK_SIZE
 290         cmpw    $0, %cx
 291         jne     ReadCylinderLoop
 292         popa
 293         ret
 294
 295 DiskError:
 296         pushw %cs
 297         popw %ds
 298         leaw ErrorString, %si
 299         movw $7, %cx
 300         jmp  PrintStringAndHalt
 301
 302 PrintStringAndHalt:
 303         movw $0xb800, %ax
 304         movw %ax, %es
 305         movw $160, %di
 306         rep
 307         movsw
 308 Halt:
 309         jmp   Halt
 310
 311 ErrorString:
 312         .byte 'S', 0x0c, 'E', 0x0c, 'r', 0x0c, 'r', 0x0c, 'o', 0x0c, 'r', 0x0c, '!', 0x0c
 313
 314         # .org     0x01fa  # Will cause build break
 315 LBAOffsetForBootSector:
 316         .long   0x0
 317
 318         # .org    0x01fe   # Will cause build break
 319         .word   0xaa55
 320
 321 #******************************************************************************
 322 #******************************************************************************
 323 #******************************************************************************
 324
 325 .equ                 DELAY_PORT, 0x0ed           # Port to use for 1uS delay
 326 .equ                 KBD_CONTROL_PORT, 0x060     # 8042 control port
 327 .equ                 KBD_STATUS_PORT, 0x064      # 8042 status port
 328 .equ                 WRITE_DATA_PORT_CMD, 0x0d1  # 8042 command to write the data port
 329 .equ                 ENABLE_A20_CMD, 0x0df       # 8042 command to enable A20
 330
 331 # .org     0x200  # Will cause build break
 332         jmp start
 333 Em64String:
 334         .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
 335
 336 start:
 337         movw %cs, %ax
 338         movw %ax, %ds
 339         movw %ax, %es
 340         movw %ax, %ss
 341         movw $MyStack, %sp
 342
 343 #        mov ax,0b800h
 344 #        mov es,ax
 345 #        mov byte ptr es:[160],'a'
 346 #        mov ax,cs
 347 #        mov es,ax
 348
 349         movl $0, %ebx
 350         leal MemoryMap, %edi
 351 MemMapLoop:
 352         movl $0xe820, %eax
 353         movl $20, %ecx
 354         movl $0x534d4150, %edx  # 0x534d4150 = 'SMAP'
 355         int  $0x15
 356         jc  MemMapDone
 357         addl $20, %edi
 358         cmpl $0, %ebx
 359         je  MemMapDone
 360         jmp MemMapLoop
 361 MemMapDone:
 362         leal MemoryMap, %eax
 363         subl %eax, %edi                     # Get the address of the memory map
 364         movl %edi, MemoryMapSize            # Save the size of the memory map
 365
 366         xorl    %ebx, %ebx
 367         movw    %cs, %bx                    # BX=segment
 368         shll    $4, %ebx                    # BX="linear" address of segment base
 369         leal    GDT_BASE(%ebx), %eax        # EAX=PHYSICAL address of gdt
 370         movl    %eax, gdtr + 2            # Put address of gdt into the gdtr
 371         leal    IDT_BASE(%ebx), %eax        # EAX=PHYSICAL address of idt
 372         movl    %eax, idtr + 2            # Put address of idt into the idtr
 373         leal    MemoryMapSize(%ebx), %edx   # Physical base address of the memory map
 374
 375         addl $0x1000, %ebx                  # Source of EFI32
 376         movl %ebx, JUMP+2
 377         addl $0x1000, %ebx
 378         movl %ebx, %esi                     # Source of EFILDR32
 379
 380 #        mov ax,0b800h
 381 #        mov es,ax
 382 #        mov byte ptr es:[162],'b'
 383 #        mov ax,cs
 384 #        mov es,ax
 385
 386 #
 387 # Enable A20 Gate
 388 #
 389
 390         movw $0x2401, %ax                   # Enable A20 Gate
 391         int $0x15
 392         jnc A20GateEnabled                  # Jump if it suceeded
 393
 394 #
 395 # If INT 15 Function 2401 is not supported, then attempt to Enable A20 manually.
 396 #
 397
 398         call    Empty8042InputBuffer        # Empty the Input Buffer on the 8042 controller
 399         jnz     Timeout8042                 # Jump if the 8042 timed out
 400         outw    %ax, $DELAY_PORT            # Delay 1 uS
 401         movb    $WRITE_DATA_PORT_CMD, %al   # 8042 cmd to write output port
 402         outb    %al, $KBD_STATUS_PORT       # Send command to the 8042
 403         call    Empty8042InputBuffer        # Empty the Input Buffer on the 8042 controller
 404         jnz     Timeout8042                 # Jump if the 8042 timed out
 405         movb    $ENABLE_A20_CMD, %al        # gate address bit 20 on
 406         outb    %al, $KBD_CONTROL_PORT      # Send command to thre 8042
 407         call    Empty8042InputBuffer        # Empty the Input Buffer on the 8042 controller
 408         movw    $25, %cx                    # Delay 25 uS for the command to complete on the 8042
 409 Delay25uS:
 410         outw    %ax, $DELAY_PORT            # Delay 1 uS
 411         loopl   Delay25uS
 412 Timeout8042:
 413
 414
 415 A20GateEnabled:
 416         movw    $0x0008, %bx                # Flat data descriptor
 417 #
 418 # DISABLE INTERRUPTS - Entering Protected Mode
 419 #
 420
 421         cli
 422
 423 #        mov ax,0b800h
 424 #        mov es,ax
 425 #        mov byte ptr es:[164],'c'
 426 #        mov ax,cs
 427 #        mov es,ax
 428
 429         .byte   0x66
 430         lgdt    gdtr
 431         .byte   0x66
 432         lidt    idtr
 433
 434         movl    %cr0, %eax
 435         orb     $1, %al
 436         movl    %eax, %cr0
 437 JUMP:
 438 # jmp far 0010:00020000
 439         .byte 0x66
 440         .byte 0xea
 441         .long 0x00020000
 442         .word 0x0010
 443
 444 Empty8042InputBuffer:
 445         movw $0, %cx
 446 Empty8042Loop:
 447         outw    %ax, $DELAY_PORT            # Delay 1us
 448         inb     $KBD_STATUS_PORT, %al       # Read the 8042 Status Port
 449         andb    $0x2, %al                   # Check the Input Buffer Full Flag
 450         loopnz  Empty8042Loop               # Loop until the input buffer is empty or a timout of 65536 uS
 451         ret
 452
 453 ##############################################################################
 454 # data
 455 ##############################################################################
 456
 457         .p2align 1
 458
 459 gdtr:    .word GDT_END - GDT_BASE - 1
 460         .long 0                     # (GDT base gets set above)
 461 ##############################################################################
 462 #   global descriptor table (GDT)
 463 ##############################################################################
 464
 465         .p2align 1
 466
 467 GDT_BASE:
 468 # null descriptor
 469 .equ                NULL_SEL, .-GDT_BASE
 470         .word 0         # limit 15:0
 471         .word 0         # base 15:0
 472         .byte 0         # base 23:16
 473         .byte 0         # type
 474         .byte 0         # limit 19:16, flags
 475         .byte 0         # base 31:24
 476
 477 # linear data segment descriptor
 478 .equ            LINEAR_SEL, .-GDT_BASE
 479         .word 0xFFFF    # limit 0xFFFFF
 480         .word 0         # base 0
 481         .byte 0
 482         .byte 0x92      # present, ring 0, data, expand-up, writable
 483         .byte 0xCF      # page-granular, 32-bit
 484         .byte 0
 485
 486 # linear code segment descriptor
 487 .equ            LINEAR_CODE_SEL, .-GDT_BASE
 488         .word 0xFFFF    # limit 0xFFFFF
 489         .word 0         # base 0
 490         .byte 0
 491         .byte 0x9A      # present, ring 0, data, expand-up, writable
 492         .byte 0xCF      # page-granular, 32-bit
 493         .byte 0
 494
 495 # system data segment descriptor
 496 .equ            SYS_DATA_SEL, .-GDT_BASE
 497         .word 0xFFFF    # limit 0xFFFFF
 498         .word 0         # base 0
 499         .byte 0
 500         .byte 0x92      # present, ring 0, data, expand-up, writable
 501         .byte 0xCF      # page-granular, 32-bit
 502         .byte 0
 503
 504 # system code segment descriptor
 505 .equ            SYS_CODE_SEL, .-GDT_BASE
 506         .word 0xFFFF    # limit 0xFFFFF
 507         .word 0         # base 0
 508         .byte 0
 509         .byte 0x9A      # present, ring 0, data, expand-up, writable
 510         .byte 0xCF      # page-granular, 32-bit
 511         .byte 0
 512
 513 # spare segment descriptor
 514 .equ        SPARE3_SEL, .-GDT_BASE
 515         .word 0         # limit 0xFFFFF
 516         .word 0         # base 0
 517         .byte 0
 518         .byte 0         # present, ring 0, data, expand-up, writable
 519         .byte 0         # page-granular, 32-bit
 520         .byte 0
 521
 522 # spare segment descriptor
 523 .equ        SPARE4_SEL, .-GDT_BASE
 524         .word 0         # limit 0xFFFFF
 525         .word 0         # base 0
 526         .byte 0
 527         .byte 0         # present, ring 0, data, expand-up, writable
 528         .byte 0         # page-granular, 32-bit
 529         .byte 0
 530
 531 # spare segment descriptor
 532 .equ        SPARE5_SEL, .-GDT_BASE
 533         .word 0         # limit 0xFFFFF
 534         .word 0         # base 0
 535         .byte 0
 536         .byte 0         # present, ring 0, data, expand-up, writable
 537         .byte 0         # page-granular, 32-bit
 538         .byte 0
 539
 540 GDT_END:
 541
 542         .p2align 1
 543
 544
 545
 546 idtr:            .word IDT_END - IDT_BASE - 1
 547         .long 0                     # (IDT base gets set above)
 548 ##############################################################################
 549 #   interrupt descriptor table (IDT)
 550 #
 551 #   Note: The hardware IRQ's specified in this table are the normal PC/AT IRQ
 552 #       mappings.  This implementation only uses the system timer and all other
 553 #       IRQs will remain masked.  The descriptors for vectors 33+ are provided
 554 #       for convenience.
 555 ##############################################################################
 556
 557 #idt_tag db "IDT",0
 558         .p2align 1
 559
 560 IDT_BASE:
 561 # divide by zero (INT 0)
 562 .equ                DIV_ZERO_SEL, .-IDT_BASE
 563         .word 0            # offset 15:0
 564         .word SYS_CODE_SEL # selector 15:0
 565         .byte 0            # 0 for interrupt gate
 566         .byte 0x0e | 0x80  # type = 386 interrupt gate, present
 567         .word 0            # offset 31:16
 568
 569 # debug exception (INT 1)
 570 .equ                DEBUG_EXCEPT_SEL, .-IDT_BASE
 571         .word 0            # offset 15:0
 572         .word SYS_CODE_SEL # selector 15:0
 573         .byte 0            # 0 for interrupt gate
 574         .byte 0x0e | 0x80  # type = 386 interrupt gate, present
 575         .word 0            # offset 31:16
 576
 577 # NMI (INT 2)
 578 .equ                NMI_SEL, .-IDT_BASE
 579         .word 0            # offset 15:0
 580         .word SYS_CODE_SEL # selector 15:0
 581         .byte 0            # 0 for interrupt gate
 582         .byte 0x0e | 0x80  # type = 386 interrupt gate, present
 583         .word 0            # offset 31:16
 584
 585 # soft breakpoint (INT 3)
 586 .equ                BREAKPOINT_SEL, .-IDT_BASE
 587         .word 0            # offset 15:0
 588         .word SYS_CODE_SEL # selector 15:0
 589         .byte 0            # 0 for interrupt gate
 590         .byte 0x0e | 0x80  # type = 386 interrupt gate, present
 591         .word 0            # offset 31:16
 592
 593 # overflow (INT 4)
 594 .equ                OVERFLOW_SEL, .-IDT_BASE
 595         .word 0            # offset 15:0
 596         .word SYS_CODE_SEL # selector 15:0
 597         .byte 0            # 0 for interrupt gate
 598         .byte 0x0e | 0x80  # type = 386 interrupt gate, present
 599         .word 0            # offset 31:16
 600
 601 # bounds check (INT 5)
 602 .equ                BOUNDS_CHECK_SEL, .-IDT_BASE
 603         .word 0            # offset 15:0
 604         .word SYS_CODE_SEL # selector 15:0
 605         .byte 0            # 0 for interrupt gate
 606         .byte 0x0e | 0x80  # type = 386 interrupt gate, present
 607         .word 0            # offset 31:16
 608
 609 # invalid opcode (INT 6)
 610 .equ                INVALID_OPCODE_SEL, .-IDT_BASE
 611         .word 0            # offset 15:0
 612         .word SYS_CODE_SEL # selector 15:0
 613         .byte 0            # 0 for interrupt gate
 614         .byte 0x0e | 0x80  # type = 386 interrupt gate, present
 615         .word 0            # offset 31:16
 616
 617 # device not available (INT 7)
 618 .equ                DEV_NOT_AVAIL_SEL, .-IDT_BASE
 619         .word 0            # offset 15:0
 620         .word SYS_CODE_SEL # selector 15:0
 621         .byte 0            # 0 for interrupt gate
 622         .byte 0x0e | 0x80  # type = 386 interrupt gate, present
 623         .word 0            # offset 31:16
 624
 625 # double fault (INT 8)
 626 .equ                DOUBLE_FAULT_SEL, .-IDT_BASE
 627         .word 0            # offset 15:0
 628         .word SYS_CODE_SEL # selector 15:0
 629         .byte 0            # 0 for interrupt gate
 630         .byte 0x0e | 0x80  # type = 386 interrupt gate, present
 631         .word 0            # offset 31:16
 632
 633 # Coprocessor segment overrun - reserved (INT 9)
 634 .equ                RSVD_INTR_SEL1, .-IDT_BASE
 635         .word 0            # offset 15:0
 636         .word SYS_CODE_SEL # selector 15:0
 637         .byte 0            # 0 for interrupt gate
 638         .byte 0x0e | 0x80  # type = 386 interrupt gate, present
 639         .word 0            # offset 31:16
 640
 641 # invalid TSS (INT 0ah)
 642 .equ                INVALID_TSS_SEL, .-IDT_BASE
 643         .word 0            # offset 15:0
 644         .word SYS_CODE_SEL # selector 15:0
 645         .byte 0            # 0 for interrupt gate
 646         .byte 0x0e | 0x80  # type = 386 interrupt gate, present
 647         .word 0            # offset 31:16
 648
 649 # segment not present (INT 0bh)
 650 .equ                SEG_NOT_PRESENT_SEL, .-IDT_BASE
 651         .word 0            # offset 15:0
 652         .word SYS_CODE_SEL # selector 15:0
 653         .byte 0            # 0 for interrupt gate
 654         .byte 0x0e | 0x80  # type = 386 interrupt gate, present
 655         .word 0            # offset 31:16
 656
 657 # stack fault (INT 0ch)
 658 .equ                STACK_FAULT_SEL, .-IDT_BASE
 659         .word 0            # offset 15:0
 660         .word SYS_CODE_SEL # selector 15:0
 661         .byte 0            # 0 for interrupt gate
 662         .byte 0x0e | 0x80  # type = 386 interrupt gate, present
 663         .word 0            # offset 31:16
 664
 665 # general protection (INT 0dh)
 666 .equ                GP_FAULT_SEL, .-IDT_BASE
 667         .word 0            # offset 15:0
 668         .word SYS_CODE_SEL # selector 15:0
 669         .byte 0            # 0 for interrupt gate
 670         .byte 0x0e | 0x80  # type = 386 interrupt gate, present
 671         .word 0            # offset 31:16
 672
 673 # page fault (INT 0eh)
 674 .equ                PAGE_FAULT_SEL, .-IDT_BASE
 675         .word 0            # offset 15:0
 676         .word SYS_CODE_SEL # selector 15:0
 677         .byte 0            # 0 for interrupt gate
 678         .byte 0x0e | 0x80  # type = 386 interrupt gate, present
 679         .word 0            # offset 31:16
 680
 681 # Intel reserved - do not use (INT 0fh)
 682 .equ                RSVD_INTR_SEL2, .-IDT_BASE
 683         .word 0            # offset 15:0
 684         .word SYS_CODE_SEL # selector 15:0
 685         .byte 0            # 0 for interrupt gate
 686         .byte 0x0e | 0x80  # type = 386 interrupt gate, present
 687         .word 0            # offset 31:16
 688
 689 # floating point error (INT 10h)
 690 .equ                FLT_POINT_ERR_SEL, .-IDT_BASE
 691         .word 0            # offset 15:0
 692         .word SYS_CODE_SEL # selector 15:0
 693         .byte 0            # 0 for interrupt gate
 694         .byte 0x0e | 0x80  # type = 386 interrupt gate, present
 695         .word 0            # offset 31:16
 696
 697 # alignment check (INT 11h)
 698 .equ                ALIGNMENT_CHECK_SEL, .-IDT_BASE
 699         .word 0            # offset 15:0
 700         .word SYS_CODE_SEL # selector 15:0
 701         .byte 0            # 0 for interrupt gate
 702         .byte 0x0e | 0x80  # type = 386 interrupt gate, present
 703         .word 0            # offset 31:16
 704
 705 # machine check (INT 12h)
 706 .equ                MACHINE_CHECK_SEL, .-IDT_BASE
 707         .word 0            # offset 15:0
 708         .word SYS_CODE_SEL # selector 15:0
 709         .byte 0            # 0 for interrupt gate
 710         .byte 0x0e | 0x80  # type = 386 interrupt gate, present
 711         .word 0            # offset 31:16
 712
 713 # SIMD floating-point exception (INT 13h)
 714 .equ                SIMD_EXCEPTION_SEL, .-IDT_BASE
 715         .word 0            # offset 15:0
 716         .word SYS_CODE_SEL # selector 15:0
 717         .byte 0            # 0 for interrupt gate
 718         .byte 0x0e | 0x80  # type = 386 interrupt gate, present
 719         .word 0            # offset 31:16
 720
 721 # 85 unspecified descriptors, First 12 of them are reserved, the rest are avail
 722         .fill 85 * 8, 1, 0
 723
 724 # IRQ 0 (System timer) - (INT 68h)
 725 .equ                IRQ0_SEL, .-IDT_BASE
 726         .word 0            # offset 15:0
 727         .word SYS_CODE_SEL # selector 15:0
 728         .byte 0            # 0 for interrupt gate
 729         .byte 0x0e | 0x80  # type = 386 interrupt gate, present
 730         .word 0            # offset 31:16
 731
 732 # IRQ 1 (8042 Keyboard controller) - (INT 69h)
 733 .equ                IRQ1_SEL, .-IDT_BASE
 734         .word 0            # offset 15:0
 735         .word SYS_CODE_SEL # selector 15:0
 736         .byte 0            # 0 for interrupt gate
 737         .byte 0x0e | 0x80  # type = 386 interrupt gate, present
 738         .word 0            # offset 31:16
 739
 740 # Reserved - IRQ 2 redirect (IRQ 2) - DO NOT USE!!! - (INT 6ah)
 741 .equ                IRQ2_SEL, .-IDT_BASE
 742         .word 0            # offset 15:0
 743         .word SYS_CODE_SEL # selector 15:0
 744         .byte 0            # 0 for interrupt gate
 745         .byte 0x0e | 0x80  # type = 386 interrupt gate, present
 746         .word 0            # offset 31:16
 747
 748 # IRQ 3 (COM 2) - (INT 6bh)
 749 .equ                IRQ3_SEL, .-IDT_BASE
 750         .word 0            # offset 15:0
 751         .word SYS_CODE_SEL # selector 15:0
 752         .byte 0            # 0 for interrupt gate
 753         .byte 0x0e | 0x80  # type = 386 interrupt gate, present
 754         .word 0            # offset 31:16
 755
 756 # IRQ 4 (COM 1) - (INT 6ch)
 757 .equ                IRQ4_SEL, .-IDT_BASE
 758         .word 0            # offset 15:0
 759         .word SYS_CODE_SEL # selector 15:0
 760         .byte 0            # 0 for interrupt gate
 761         .byte 0x0e | 0x80  # type = 386 interrupt gate, present
 762         .word 0            # offset 31:16
 763
 764 # IRQ 5 (LPT 2) - (INT 6dh)
 765 .equ                IRQ5_SEL, .-IDT_BASE
 766         .word 0            # offset 15:0
 767         .word SYS_CODE_SEL # selector 15:0
 768         .byte 0            # 0 for interrupt gate
 769         .byte 0x0e | 0x80  # type = 386 interrupt gate, present
 770         .word 0            # offset 31:16
 771
 772 # IRQ 6 (Floppy controller) - (INT 6eh)
 773 .equ                IRQ6_SEL, .-IDT_BASE
 774         .word 0            # offset 15:0
 775         .word SYS_CODE_SEL # selector 15:0
 776         .byte 0            # 0 for interrupt gate
 777         .byte 0x0e | 0x80  # type = 386 interrupt gate, present
 778         .word 0            # offset 31:16
 779
 780 # IRQ 7 (LPT 1) - (INT 6fh)
 781 .equ                IRQ7_SEL, .-IDT_BASE
 782         .word 0            # offset 15:0
 783         .word SYS_CODE_SEL # selector 15:0
 784         .byte 0            # 0 for interrupt gate
 785         .byte 0x0e | 0x80  # type = 386 interrupt gate, present
 786         .word 0            # offset 31:16
 787
 788 # IRQ 8 (RTC Alarm) - (INT 70h)
 789 .equ                IRQ8_SEL, .-IDT_BASE
 790         .word 0            # offset 15:0
 791         .word SYS_CODE_SEL # selector 15:0
 792         .byte 0            # 0 for interrupt gate
 793         .byte 0x0e | 0x80  # type = 386 interrupt gate, present
 794         .word 0            # offset 31:16
 795
 796 # IRQ 9 - (INT 71h)
 797 .equ                IRQ9_SEL, .-IDT_BASE
 798         .word 0            # offset 15:0
 799         .word SYS_CODE_SEL # selector 15:0
 800         .byte 0            # 0 for interrupt gate
 801         .byte 0x0e | 0x80  # type = 386 interrupt gate, present
 802         .word 0            # offset 31:16
 803
 804 # IRQ 10 - (INT 72h)
 805 .equ                 IRQ10_SEL, .-IDT_BASE
 806         .word 0            # offset 15:0
 807         .word SYS_CODE_SEL # selector 15:0
 808         .byte 0            # 0 for interrupt gate
 809         .byte 0x0e | 0x80  # type = 386 interrupt gate, present
 810         .word 0            # offset 31:16
 811
 812 # IRQ 11 - (INT 73h)
 813 .equ                 IRQ11_SEL, .-IDT_BASE
 814         .word 0            # offset 15:0
 815         .word SYS_CODE_SEL # selector 15:0
 816         .byte 0            # 0 for interrupt gate
 817         .byte 0x0e | 0x80  # type = 386 interrupt gate, present
 818         .word 0            # offset 31:16
 819
 820 # IRQ 12 (PS/2 mouse) - (INT 74h)
 821 .equ                 IRQ12_SEL, .-IDT_BASE
 822         .word 0            # offset 15:0
 823         .word SYS_CODE_SEL # selector 15:0
 824         .byte 0            # 0 for interrupt gate
 825         .byte 0x0e | 0x80  # type = 386 interrupt gate, present
 826         .word 0            # offset 31:16
 827
 828 # IRQ 13 (Floating point error) - (INT 75h)
 829 .equ                 IRQ13_SEL, .-IDT_BASE
 830         .word 0            # offset 15:0
 831         .word SYS_CODE_SEL # selector 15:0
 832         .byte 0            # 0 for interrupt gate
 833         .byte 0x0e | 0x80  # type = 386 interrupt gate, present
 834         .word 0            # offset 31:16
 835
 836 # IRQ 14 (Secondary IDE) - (INT 76h)
 837 .equ                 IRQ14_SEL, .-IDT_BASE
 838         .word 0            # offset 15:0
 839         .word SYS_CODE_SEL # selector 15:0
 840         .byte 0            # 0 for interrupt gate
 841         .byte 0x0e | 0x80  # type = 386 interrupt gate, present
 842         .word 0            # offset 31:16
 843
 844 # IRQ 15 (Primary IDE) - (INT 77h)
 845 .equ                 IRQ15_SEL, .-IDT_BASE
 846         .word 0            # offset 15:0
 847         .word SYS_CODE_SEL # selector 15:0
 848         .byte 0            # 0 for interrupt gate
 849         .byte 0x0e | 0x80  # type = 386 interrupt gate, present
 850         .word 0            # offset 31:16
 851
 852 IDT_END:
 853
 854         .p2align 1
 855
 856 MemoryMapSize:  .long 0
 857 MemoryMap:  .long 0,0,0,0,0,0,0,0
 858         .long 0,0,0,0,0,0,0,0
 859         .long 0,0,0,0,0,0,0,0
 860         .long 0,0,0,0,0,0,0,0
 861         .long 0,0,0,0,0,0,0,0
 862         .long 0,0,0,0,0,0,0,0
 863         .long 0,0,0,0,0,0,0,0
 864         .long 0,0,0,0,0,0,0,0
 865         .long 0,0,0,0,0,0,0,0
 866         .long 0,0,0,0,0,0,0,0
 867         .long 0,0,0,0,0,0,0,0
 868         .long 0,0,0,0,0,0,0,0
 869         .long 0,0,0,0,0,0,0,0
 870         .long 0,0,0,0,0,0,0,0
 871         .long 0,0,0,0,0,0,0,0
 872         .long 0,0,0,0,0,0,0,0
 873         .long 0,0,0,0,0,0,0,0
 874         .long 0,0,0,0,0,0,0,0
 875         .long 0,0,0,0,0,0,0,0
 876         .long 0,0,0,0,0,0,0,0
 877         .long 0,0,0,0,0,0,0,0
 878         .long 0,0,0,0,0,0,0,0
 879         .long 0,0,0,0,0,0,0,0
 880         .long 0,0,0,0,0,0,0,0
 881         .long 0,0,0,0,0,0,0,0
 882         .long 0,0,0,0,0,0,0,0
 883         .long 0,0,0,0,0,0,0,0
 884         .long 0,0,0,0,0,0,0,0
 885         .long 0,0,0,0,0,0,0,0
 886         .long 0,0,0,0,0,0,0,0
 887
 888         .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
 889         .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
 890
 891         .org 0x0fe0
 892 MyStack:
 893         # below is the pieces of the IVT that is used to redirect INT 68h - 6fh
 894         #    back to INT 08h - 0fh  when in real mode...  It is 'org'ed to a
 895         #    known low address (20f00) so it can be set up by PlMapIrqToVect in
 896         #    8259.c
 897
 898         int $8
 899         iret
 900
 901         int $9
 902         iret
 903
 904         int $10
 905         iret
 906
 907         int $11
 908         iret
 909
 910         int $12
 911         iret
 912
 913         int $13
 914         iret
 915
 916         int $14
 917         iret
 918
 919         int $15
 920         iret
 921
 922
 923         .org 0x0ffe
 924 BlockSignature:
 925         .word 0xaa55
 926
 927