DuetPkg/CpuDxe/Ia32/CpuInterrupt.S

   1 /** @file
   2  *
   3  *   Copyright 2006, 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  *    CpuInterrupt.S
  13  *
  14  *   Abstract:
  15  *
  16  **/
  17
  18 .globl ASM_PFX(SystemTimerHandler)
  19 .globl ASM_PFX(SystemExceptionHandler)
  20 .globl ASM_PFX(mExceptionCodeSize)
  21 .globl ASM_PFX(InitDescriptor)
  22 .globl ASM_PFX(InstallInterruptHandler)
  23
  24 ASM_PFX(mExceptionCodeSize):  .long  9
  25
  26 /**
  27  * VOID
  28  * InitDescriptor (
  29  * VOID
  30  * )
  31  **/
  32 ASM_PFX(InitDescriptor):
  33         lgdt    gdtr
  34         lidt    idtr
  35         ret
  36
  37 /**
  38  * VOID
  39  * InstallInterruptHandler (
  40  *     UINTN Vector,
  41  *     VOID  (*Handler)(VOID)
  42  *     )
  43  **/
  44 ASM_PFX(InstallInterruptHandler):
  45         movl    %esp, %ebp
  46         pushl   %edi
  47         pushfl                              # save eflags
  48         cli                                 # turn off interrupts
  49         subl    $6, %esp                    # open some space on the stack
  50         movl    %esp, %edi
  51         sidt    %es:(%edi)                  # get fword address of IDT
  52         movl    %es:2(%edi), %edi            # move offset of IDT into EDI
  53         addl    $6, %esp                    # correct stack
  54         mov     4(%ebp), %eax               # Get vector number
  55         shll    $3, %eax                    # multiply by 8 to get offset
  56         addl    %eax, %edi                  # add to IDT base to get entry
  57         movl    8(%ebp), %eax               # load new address into IDT entry
  58         movw    %ax, %es:(%edi)             # write bits 15..0 of offset
  59         shrl    $16, %eax                   # use ax to copy 31..16 to descriptors
  60         movw    %ax, %es:6(%edi)            # write bits 31..16 of offset
  61         popfl                               # restore flags (possible enabling interrupts)
  62         pop     %edi
  63         ret
  64
  65 .macro JmpCommonIdtEntry  errno, vector
  66     /* jmp     commonIdtEntry - this must be hand coded to keep the assembler from
  67      *                          using a 8 bit reletive jump when the entries are
  68      *                          within 255 bytes of the common entry.  This must
  69      *                          be done to maintain the consistency of the size
  70      *                          of entry points...
  71      */
  72     pushl \errno
  73     pushl \vector
  74     #.byte   0e9h                         # jmp 16 bit reletive
  75     #.long   commonIdtEntry - $ - $4      #  offset to jump to
  76     jmpl *commonIdtEntry
  77 .endm
  78
  79 .align 0x02
  80 ASM_PFX(SystemExceptionHandler):
  81 INT0:
  82     JmpCommonIdtEntry  errno=0,vector=0
  83 INT1:
  84     JmpCommonIdtEntry  errno=0,vector=1
  85 INT2:
  86     JmpCommonIdtEntry  errno=0,vector=2
  87 INT3:
  88     JmpCommonIdtEntry  errno=0,vector=3
  89 INT4:
  90     JmpCommonIdtEntry  errno=0,vector=4
  91 INT5:
  92     JmpCommonIdtEntry  errno=0,vector=5
  93 INT6:
  94     JmpCommonIdtEntry  errno=0,vector=6
  95 INT7:
  96     JmpCommonIdtEntry  errno=0,vector=7
  97 INT8:
  98 #   Double fault causes an error code to be pushed so no phony pushl necessary
  99     nop
 100     nop
 101     pushl    $8
 102     jmpl *commonIdtEntry
 103 INT9:
 104     JmpCommonIdtEntry  errno=0,vector=9
 105 INT10:
 106 #   Invalid TSS causes an error code to be pushed so no phony pushl necessary
 107     nop
 108     nop
 109     pushl    $10
 110     jmpl *commonIdtEntry
 111 INT11:
 112 #   Segment Not Present causes an error code to be pushed so no phony pushl necessary
 113     nop
 114     nop
 115     pushl    $11
 116     jmpl *commonIdtEntry
 117 INT12:
 118 #   Stack fault causes an error code to be pushed so no phony pushl necessary
 119     nop
 120     nop
 121     pushl    $12
 122     jmpl *commonIdtEntry
 123 INT13:
 124 #   GP fault causes an error code to be pushed so no phony pushl necessary
 125     nop
 126     nop
 127     pushl    $13
 128     jmpl *commonIdtEntry
 129 INT14:
 130 #   Page fault causes an error code to be pushed so no phony pushl necessary
 131     nop
 132     nop
 133     pushl    $14
 134     jmpl *commonIdtEntry
 135 INT15:
 136     JmpCommonIdtEntry  errno=0,vector=15
 137 INT16:
 138     JmpCommonIdtEntry  errno=0,vector=16
 139 INT17:
 140 #   Alignment check causes an error code to be pushed so no phony pushl necessary
 141     nop
 142     nop
 143     pushl    $17
 144     jmpl *commonIdtEntry
 145 INT18:
 146     JmpCommonIdtEntry  errno=0,vector=18
 147 INT19:
 148     JmpCommonIdtEntry  errno=0,vector=19
 149 INTUnknown:
 150     JmpCommonIdtEntry  errno=0,vector=20
 151     JmpCommonIdtEntry  errno=0,vector=21
 152     JmpCommonIdtEntry  errno=0,vector=22
 153     JmpCommonIdtEntry  errno=0,vector=23
 154     JmpCommonIdtEntry  errno=0,vector=24
 155     JmpCommonIdtEntry  errno=0,vector=25
 156     JmpCommonIdtEntry  errno=0,vector=26
 157     JmpCommonIdtEntry  errno=0,vector=27
 158     JmpCommonIdtEntry  errno=0,vector=28
 159     JmpCommonIdtEntry  errno=0,vector=29
 160     JmpCommonIdtEntry  errno=0,vector=30
 161     JmpCommonIdtEntry  errno=0,vector=31
 162
 163 ASM_PFX(SystemTimerHandler):
 164     JmpCommonIdtEntry  errno=0,vector=ASM_PFX(mTimerVector)
 165
 166 commonIdtEntry:
 167 # +---------------------+
 168 # +    EFlags           +
 169 # +---------------------+
 170 # +    CS               +
 171 # +---------------------+
 172 # +    EIP              +
 173 # +---------------------+
 174 # +    Error Code       +
 175 # +---------------------+
 176 # +    Vector Number    +
 177 # +---------------------+
 178 # +    EBP              +
 179 # +---------------------+ <-- EBP
 180
 181   cli
 182   pushl %ebp
 183   movl  %esp, %ebp
 184
 185   #
 186   # Align stack to make sure that EFI_FX_SAVE_STATE_IA32 of EFI_SYSTEM_CONTEXT_IA32
 187   # is 16-byte aligned
 188   #
 189   andl    $0xfffffff0, %esp
 190   subl    $12, %esp
 191
 192 ## UINT32  Edi, Esi, Ebp, Esp, Ebx, Edx, Ecx, Eax#
 193   pushl    %eax
 194   pushl    %ecx
 195   pushl    %edx
 196   pushl    %ebx
 197   leal     24(%ebp), %ecx
 198   pushl    %ecx                # ESP
 199   pushl    (%ebp)              # EBP
 200   pushl    %esi
 201   pushl    %edi
 202
 203 ## UINT32  Gs, Fs, Es, Ds, Cs, Ss#
 204   movl     %ss, %eax
 205   pushl    %eax
 206   movzwl   16(%ebp), %eax
 207   pushl    %eax
 208   movl     %ds, %eax
 209   pushl    %eax
 210   movl     %es, %eax
 211   pushl    %eax
 212   movl     %fs, %eax
 213   pushl    %eax
 214   movl     %gs, %eax
 215   pushl    %eax
 216
 217 ## UINT32  Eip#
 218   pushl    12(%ebp)
 219
 220 ## UINT32  Gdtr[2], Idtr[2]#
 221   subl     $8, %esp
 222   sidt     (%esp)
 223   subl     $8, %esp
 224   sgdt     (%esp)
 225
 226 ## UINT32  Ldtr, Tr#
 227   xorl     %eax, %eax
 228   strw     %ax
 229   pushl    %eax
 230   sldt     %ax
 231   pushl    %eax
 232
 233 ## UINT32  EFlags#
 234   pushl   5*4(%ebp)
 235
 236 ## UINT32  Cr0, Cr1, Cr2, Cr3, Cr4#
 237   movl %cr4, %eax
 238   orl  $0x208, %eax
 239   movl %eax, %cr4
 240   pushl %eax
 241   movl %cr3, %eax
 242   pushl %eax
 243   movl %cr2, %eax
 244   pushl %eax
 245   xorl %eax, %eax
 246   pushl %eax
 247   movl %cr0, %eax
 248   pushl %eax
 249
 250 ## UINT32  Dr0, Dr1, Dr2, Dr3, Dr6, Dr7#
 251   movl    %dr7, %eax
 252   pushl   %eax
 253 ## clear Dr7 while executing debugger itself
 254   xorl    %eax, %eax
 255   movl    %eax, %dr7
 256
 257   movl    %dr6, %eax
 258   pushl   %eax
 259 ## insure all status bits in dr6 are clear...
 260   xorl    %eax, %eax
 261   movl    %eax, %dr6
 262
 263   movl    %dr3, %eax
 264   pushl   %eax
 265   movl    %dr2, %eax
 266   pushl   %eax
 267   movl    %dr1, %eax
 268   pushl   %eax
 269   movl    %dr0, %eax
 270   pushl   %eax
 271
 272 ## FX_SAVE_STATE_IA32 FxSaveState#
 273   subl $512, %esp
 274   movl %esp, %edi
 275   #.byte 0f, 0ae, 00000111y #fxsave [edi]
 276   fxsave (%edi)
 277
 278 ## UINT32  ExceptionData#
 279   pushl    2*4(%ebp)
 280
 281 ## Prepare parameter and call
 282   movl    %esp, %edx
 283   pushl   %edx
 284   movl    1*4(%ebp), %eax
 285   pushl   %eax
 286   cmpl    $32, %eax
 287   jb      CallException
 288   call    ASM_PFX(TimerHandler)
 289   jmp     ExceptionDone
 290 CallException:
 291   call    ASM_PFX(ExceptionHandler)
 292 ExceptionDone:
 293   addl    $8, %esp
 294
 295   cli
 296 ## UINT32  ExceptionData#
 297   addl    $4, %esp
 298
 299 ## FX_SAVE_STATE_IA32 FxSaveState#
 300   movl %esp, %esi
 301   #db 0fh, 0aeh, 00001110y # fxrstor [esi]
 302   fxrstor (%esi)
 303   addl $512, %esp
 304
 305 ## UINT32  Dr0, Dr1, Dr2, Dr3, Dr6, Dr7#
 306   popl    %eax
 307   movl    %eax, %dr0
 308   popl    %eax
 309   movl    %eax, %dr1
 310   popl    %eax
 311   movl    %eax, %dr2
 312   popl    %eax
 313   movl    %eax, %dr3
 314 ## skip restore of dr6.  We cleared dr6 during the context save.
 315   addl    $4, %esp
 316   popl    %eax
 317   movl    %eax, %dr7
 318
 319 ## UINT32  Cr0, Cr1, Cr2, Cr3, Cr4#
 320   popl    %eax
 321   movl    %eax, %cr0
 322   addl    $4, %esp  # not for Cr1
 323   popl    %eax
 324   movl    %eax, %cr2
 325   popl    %eax
 326   movl    %eax, %cr3
 327   popl    %eax
 328   movl    %eax, %cr4
 329
 330 ## UINT32  EFlags#
 331   popl    5*4(%ebp)
 332
 333 ## UINT32  Ldtr, Tr#
 334 ## UINT32  Gdtr[2], Idtr[2]#
 335 ## Best not let anyone mess with these particular registers...
 336   addl    $24, %esp
 337
 338 ## UINT32  Eip#
 339   popl    3*4(%ebp)
 340
 341 ## UINT32  Gs, Fs, Es, Ds, Cs, Ss#
 342 ## NOTE - modified segment registers could hang the debugger...  We
 343 ##        could attempt to insulate ourselves against this possibility,
 344 ##        but that poses risks as well.
 345 ##
 346   popl    %gs
 347   popl    %fs
 348   popl    %es
 349   popl    %ds
 350   popl    4*4(%ebp)
 351   popl    %ss
 352
 353 ## UINT32  Edi, Esi, Ebp, Esp, Ebx, Edx, Ecx, Eax#
 354   popl    %edi
 355   popl    %esi
 356   addl    $4, %esp # not for ebp
 357   addl    $4, %esp # not for esp
 358   popl    %ebx
 359   popl    %edx
 360   popl    %ecx
 361   popl    %eax
 362
 363   movl    %ebp, %esp
 364   popl    %ebp
 365   addl    $8, %esp
 366   iretl
 367
 368
 369 ##############################################################################
 370 # data
 371 ##############################################################################
 372
 373 .align 2, 0x0
 374 gdtr:
 375     .word 8*8 - 1
 376     .long GDT_BASE
 377
 378 ##############################################################################
 379 #   global descriptor table (GDT)
 380 ##############################################################################
 381
 382
 383 .align 2, 0x90
 384 GDT_BASE:
 385     .quad 0x0                   // null descriptor
 386     .quad 0x00cf92000000ffff    // linear data segment descriptor
 387     .quad 0x00cf9a000000ffff    // linear code segment descriptor
 388     .quad 0x00cf92000000ffff    // system data segment descriptor
 389     .quad 0x00cf9a000000ffff    // system code segment descriptor
 390     .quad 0x0                   // spare segment descriptor
 391     .quad 0x0
 392     .quad 0x0
 393
 394 .align 0x02
 395
 396 idtr:
 397     .word IDT_END - IDT_BASE - 1   # IDT limit
 398     .long IDT_BASE
 399
 400 ##############################################################################
 401 #   interrupt descriptor table (IDT)
 402 #
 403 #   Note: The hardware IRQ's specified in this table are the normal PC/AT IRQ
 404 #       mappings.  This implementation only uses the system timer and all other
 405 #       IRQs will remain masked.  The descriptors for vectors 33+ are provided
 406 #       for convenience.
 407 ##############################################################################
 408
 409 .align 0x02
 410
 411 IDT_BASE:
 412      .skip 256 * 16
 413
 414 /**
 415 # divide by zero (INT 0)
 416 DIV_ZERO_SEL        equ $-IDT_BASE
 417         dw 0            # offset 15:0
 418         dw SYS_CODE_SEL # selector 15:0
 419         db 0            # 0 for interrupt gate
 420         db 0eh OR 80h   # type = 386 interrupt gate, present
 421         dw 0            # offset 31:16
 422
 423 # debug exception (INT 1)
 424 DEBUG_EXCEPT_SEL    equ $-IDT_BASE
 425         dw 0            # offset 15:0
 426         dw SYS_CODE_SEL # selector 15:0
 427         db 0            # 0 for interrupt gate
 428         db 0eh OR 80h   # type = 386 interrupt gate, present
 429         dw 0            # offset 31:16
 430
 431 # NMI (INT 2)
 432 NMI_SEL             equ $-IDT_BASE
 433         dw 0            # offset 15:0
 434         dw SYS_CODE_SEL # selector 15:0
 435         db 0            # 0 for interrupt gate
 436         db 0eh OR 80h   # type = 386 interrupt gate, present
 437         dw 0            # offset 31:16
 438
 439 # soft breakpoint (INT 3)
 440 BREAKPOINT_SEL      equ $-IDT_BASE
 441         dw 0            # offset 15:0
 442         dw SYS_CODE_SEL # selector 15:0
 443         db 0            # 0 for interrupt gate
 444         db 0eh OR 80h   # type = 386 interrupt gate, present
 445         dw 0            # offset 31:16
 446
 447 # overflow (INT 4)
 448 OVERFLOW_SEL        equ $-IDT_BASE
 449         dw 0            # offset 15:0
 450         dw SYS_CODE_SEL # selector 15:0
 451         db 0            # 0 for interrupt gate
 452         db 0eh OR 80h   # type = 386 interrupt gate, present
 453         dw 0            # offset 31:16
 454
 455 # bounds check (INT 5)
 456 BOUNDS_CHECK_SEL    equ $-IDT_BASE
 457         dw 0            # offset 15:0
 458         dw SYS_CODE_SEL # selector 15:0
 459         db 0            # 0 for interrupt gate
 460         db 0eh OR 80h   # type = 386 interrupt gate, present
 461         dw 0            # offset 31:16
 462
 463 # invalid opcode (INT 6)
 464 INVALID_OPCODE_SEL  equ $-IDT_BASE
 465         dw 0            # offset 15:0
 466         dw SYS_CODE_SEL # selector 15:0
 467         db 0            # 0 for interrupt gate
 468         db 0eh OR 80h   # type = 386 interrupt gate, present
 469         dw 0            # offset 31:16
 470
 471 # device not available (INT 7)
 472 DEV_NOT_AVAIL_SEL   equ $-IDT_BASE
 473         dw 0            # offset 15:0
 474         dw SYS_CODE_SEL # selector 15:0
 475         db 0            # 0 for interrupt gate
 476         db 0eh OR 80h   # type = 386 interrupt gate, present
 477         dw 0            # offset 31:16
 478
 479 # double fault (INT 8)
 480 DOUBLE_FAULT_SEL    equ $-IDT_BASE
 481         dw 0            # offset 15:0
 482         dw SYS_CODE_SEL # selector 15:0
 483         db 0            # 0 for interrupt gate
 484         db 0eh OR 80h   # type = 386 interrupt gate, present
 485         dw 0            # offset 31:16
 486
 487 # Coprocessor segment overrun - reserved (INT 9)
 488 RSVD_INTR_SEL1      equ $-IDT_BASE
 489         dw 0            # offset 15:0
 490         dw SYS_CODE_SEL # selector 15:0
 491         db 0            # 0 for interrupt gate
 492         db 0eh OR 80h   # type = 386 interrupt gate, present
 493         dw 0            # offset 31:16
 494
 495 # invalid TSS (INT 0ah)
 496 INVALID_TSS_SEL     equ $-IDT_BASE
 497         dw 0            # offset 15:0
 498         dw SYS_CODE_SEL # selector 15:0
 499         db 0            # 0 for interrupt gate
 500         db 0eh OR 80h   # type = 386 interrupt gate, present
 501         dw 0            # offset 31:16
 502
 503 # segment not present (INT 0bh)
 504 SEG_NOT_PRESENT_SEL equ $-IDT_BASE
 505         dw 0            # offset 15:0
 506         dw SYS_CODE_SEL # selector 15:0
 507         db 0            # 0 for interrupt gate
 508         db 0eh OR 80h   # type = 386 interrupt gate, present
 509         dw 0            # offset 31:16
 510
 511 # stack fault (INT 0ch)
 512 STACK_FAULT_SEL     equ $-IDT_BASE
 513         dw 0            # offset 15:0
 514         dw SYS_CODE_SEL # selector 15:0
 515         db 0            # 0 for interrupt gate
 516         db 0eh OR 80h   # type = 386 interrupt gate, present
 517         dw 0            # offset 31:16
 518
 519 # general protection (INT 0dh)
 520 GP_FAULT_SEL        equ $-IDT_BASE
 521         dw 0            # offset 15:0
 522         dw SYS_CODE_SEL # selector 15:0
 523         db 0            # 0 for interrupt gate
 524         db 0eh OR 80h   # type = 386 interrupt gate, present
 525         dw 0            # offset 31:16
 526
 527 # page fault (INT 0eh)
 528 PAGE_FAULT_SEL      equ $-IDT_BASE
 529         dw 0            # offset 15:0
 530         dw SYS_CODE_SEL # selector 15:0
 531         db 0            # 0 for interrupt gate
 532         db 0eh OR 80h   # type = 386 interrupt gate, present
 533         dw 0            # offset 31:16
 534
 535 # Intel reserved - do not use (INT 0fh)
 536 RSVD_INTR_SEL2      equ $-IDT_BASE
 537         dw 0            # offset 15:0
 538         dw SYS_CODE_SEL # selector 15:0
 539         db 0            # 0 for interrupt gate
 540         db 0eh OR 80h   # type = 386 interrupt gate, present
 541         dw 0            # offset 31:16
 542
 543 # floating point error (INT 10h)
 544 FLT_POINT_ERR_SEL   equ $-IDT_BASE
 545         dw 0            # offset 15:0
 546         dw SYS_CODE_SEL # selector 15:0
 547         db 0            # 0 for interrupt gate
 548         db 0eh OR 80h   # type = 386 interrupt gate, present
 549         dw 0            # offset 31:16
 550
 551 # alignment check (INT 11h)
 552 ALIGNMENT_CHECK_SEL equ $-IDT_BASE
 553         dw 0            # offset 15:0
 554         dw SYS_CODE_SEL # selector 15:0
 555         db 0            # 0 for interrupt gate
 556         db 0eh OR 80h   # (10001110)type = 386 interrupt gate, present
 557         dw 0            # offset 31:16
 558
 559 # machine check (INT 12h)
 560 MACHINE_CHECK_SEL   equ $-IDT_BASE
 561         dw 0            # offset 15:0
 562         dw SYS_CODE_SEL # selector 15:0
 563         db 0            # 0 for interrupt gate
 564         db 0eh OR 80h   # (10001110)type = 386 interrupt gate, present
 565         dw 0            # offset 31:16
 566
 567 # SIMD floating-point exception (INT 13h)
 568 SIMD_EXCEPTION_SEL  equ $-IDT_BASE
 569         dw 0            # offset 15:0
 570         dw SYS_CODE_SEL # selector 15:0
 571         db 0            # 0 for interrupt gate
 572         db 0eh OR 80h   # (10001110)type = 386 interrupt gate, present
 573         dw 0            # offset 31:16
 574
 575 REPEAT  (32 - 20)
 576         dw 0            # offset 15:0
 577         dw SYS_CODE_SEL # selector 15:0
 578         db 0            # 0 for interrupt gate
 579         db 0eh OR 80h   # (10001110)type = 386 interrupt gate, present
 580         dw 0            # offset 31:16
 581 ENDM
 582
 583 # 72 unspecified descriptors
 584         db (72 * 8) dup(0)
 585
 586 # IRQ 0 (System timer) - (INT 68h)
 587 IRQ0_SEL            equ $-IDT_BASE
 588         dw 0            # offset 15:0
 589         dw SYS_CODE_SEL # selector 15:0
 590         db 0            # 0 for interrupt gate
 591         db 0eh OR 80h   # (10001110)type = 386 interrupt gate, present
 592         dw 0            # offset 31:16
 593
 594 # IRQ 1 (8042 Keyboard controller) - (INT 69h)
 595 IRQ1_SEL            equ $-IDT_BASE
 596         dw 0            # offset 15:0
 597         dw SYS_CODE_SEL # selector 15:0
 598         db 0            # 0 for interrupt gate
 599         db 0eh OR 80h   # (10001110)type = 386 interrupt gate, present
 600         dw 0            # offset 31:16
 601
 602 # Reserved - IRQ 2 redirect (IRQ 2) - DO NOT USE!!! - (INT 6ah)
 603 IRQ2_SEL            equ $-IDT_BASE
 604         dw 0            # offset 15:0
 605         dw SYS_CODE_SEL # selector 15:0
 606         db 0            # 0 for interrupt gate
 607         db 0eh OR 80h   # (10001110)type = 386 interrupt gate, present
 608         dw 0            # offset 31:16
 609
 610 # IRQ 3 (COM 2) - (INT 6bh)
 611 IRQ3_SEL            equ $-IDT_BASE
 612         dw 0            # offset 15:0
 613         dw SYS_CODE_SEL # selector 15:0
 614         db 0            # 0 for interrupt gate
 615         db 0eh OR 80h   # (10001110)type = 386 interrupt gate, present
 616         dw 0            # offset 31:16
 617
 618 # IRQ 4 (COM 1) - (INT 6ch)
 619 IRQ4_SEL            equ $-IDT_BASE
 620         dw 0            # offset 15:0
 621         dw SYS_CODE_SEL # selector 15:0
 622         db 0            # 0 for interrupt gate
 623         db 0eh OR 80h   # (10001110)type = 386 interrupt gate, present
 624         dw 0            # offset 31:16
 625
 626 # IRQ 5 (LPT 2) - (INT 6dh)
 627 IRQ5_SEL            equ $-IDT_BASE
 628         dw 0            # offset 15:0
 629         dw SYS_CODE_SEL # selector 15:0
 630         db 0            # 0 for interrupt gate
 631         db 0eh OR 80h   # (10001110)type = 386 interrupt gate, present
 632         dw 0            # offset 31:16
 633
 634 # IRQ 6 (Floppy controller) - (INT 6eh)
 635 IRQ6_SEL            equ $-IDT_BASE
 636         dw 0            # offset 15:0
 637         dw SYS_CODE_SEL # selector 15:0
 638         db 0            # 0 for interrupt gate
 639         db 0eh OR 80h   # (10001110)type = 386 interrupt gate, present
 640         dw 0            # offset 31:16
 641
 642 # IRQ 7 (LPT 1) - (INT 6fh)
 643 IRQ7_SEL            equ $-IDT_BASE
 644         dw 0            # offset 15:0
 645         dw SYS_CODE_SEL # selector 15:0
 646         db 0            # 0 for interrupt gate
 647         db 0eh OR 80h   # (10001110)type = 386 interrupt gate, present
 648         dw 0            # offset 31:16
 649
 650 # IRQ 8 (RTC Alarm) - (INT 70h)
 651 IRQ8_SEL            equ $-IDT_BASE
 652         dw 0            # offset 15:0
 653         dw SYS_CODE_SEL # selector 15:0
 654         db 0            # 0 for interrupt gate
 655         db 0eh OR 80h   # (10001110)type = 386 interrupt gate, present
 656         dw 0            # offset 31:16
 657
 658 # IRQ 9 - (INT 71h)
 659 IRQ9_SEL            equ $-IDT_BASE
 660         dw 0            # offset 15:0
 661         dw SYS_CODE_SEL # selector 15:0
 662         db 0            # 0 for interrupt gate
 663         db 0eh OR 80h   # (10001110)type = 386 interrupt gate, present
 664         dw 0            # offset 31:16
 665
 666 # IRQ 10 - (INT 72h)
 667 IRQ10_SEL            equ $-IDT_BASE
 668         dw 0            # offset 15:0
 669         dw SYS_CODE_SEL # selector 15:0
 670         db 0            # 0 for interrupt gate
 671         db 0eh OR 80h   # (10001110)type = 386 interrupt gate, present
 672         dw 0            # offset 31:16
 673
 674 # IRQ 11 - (INT 73h)
 675 IRQ11_SEL            equ $-IDT_BASE
 676         dw 0            # offset 15:0
 677         dw SYS_CODE_SEL # selector 15:0
 678         db 0            # 0 for interrupt gate
 679         db 0eh OR 80h   # (10001110)type = 386 interrupt gate, present
 680         dw 0            # offset 31:16
 681
 682 # IRQ 12 (PS/2 mouse) - (INT 74h)
 683 IRQ12_SEL            equ $-IDT_BASE
 684         dw 0            # offset 15:0
 685         dw SYS_CODE_SEL # selector 15:0
 686         db 0            # 0 for interrupt gate
 687         db 0eh OR 80h   # (10001110)type = 386 interrupt gate, present
 688         dw 0            # offset 31:16
 689
 690 # IRQ 13 (Floating point error) - (INT 75h)
 691 IRQ13_SEL            equ $-IDT_BASE
 692         dw 0            # offset 15:0
 693         dw SYS_CODE_SEL # selector 15:0
 694         db 0            # 0 for interrupt gate
 695         db 0eh OR 80h   # (10001110)type = 386 interrupt gate, present
 696         dw 0            # offset 31:16
 697
 698 # IRQ 14 (Secondary IDE) - (INT 76h)
 699 IRQ14_SEL            equ $-IDT_BASE
 700         dw 0            # offset 15:0
 701         dw SYS_CODE_SEL # selector 15:0
 702         db 0            # 0 for interrupt gate
 703         db 0eh OR 80h   # (10001110)type = 386 interrupt gate, present
 704         dw 0            # offset 31:16
 705
 706 # IRQ 15 (Primary IDE) - (INT 77h)
 707 IRQ15_SEL            equ $-IDT_BASE
 708         dw 0            # offset 15:0
 709         dw SYS_CODE_SEL # selector 15:0
 710         db 0            # 0 for interrupt gate
 711         db 0eh OR 80h   # (10001110)type = 386 interrupt gate, present
 712         dw 0            # offset 31:16
 713
 714         db (1 * 8) dup(0)
 715
 716 **/
 717 IDT_END: