summaryrefslogtreecommitdiff
path: root/DuetPkg/CpuDxe/Ia32/CpuInterrupt.S
blob: baf0ba35e6f0ab954141c1489bb456a167632029 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
#------------------------------------------------------------------------------
#*
#*   Copyright 2006, Intel Corporation                                                         
#*   All rights reserved. This program and the accompanying materials                          
#*   are licensed and made available under the terms and conditions of the BSD License         
#*   which accompanies this distribution.  The full text of the license may be found at        
#*   http://opensource.org/licenses/bsd-license.php                                            
#*                                                                                             
#*   THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,                     
#*   WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.             
#*   
#*    CpuInterrupt.S
#*  
#*   Abstract:
#*
#------------------------------------------------------------------------------

#PUBLIC SystemTimerHandler
#PUBLIC SystemExceptionHandler
#EXTERNDEF mExceptionCodeSize:DWORD

#EXTERN TimerHandler: NEAR
#EXTERN ExceptionHandler: NEAR
#EXTERN mTimerVector: DWORD

  .data
  ASM_GLOBAL ASM_PFX(mExceptionCodeSize)
ASM_PFX(mExceptionCodeSize): .long  9

  .text
  ASM_GLOBAL ASM_PFX(InitDescriptor)

ASM_PFX(InitDescriptor):
        movl    $GDT_BASE,%eax              # EAX=PHYSICAL address of gdt
        movl    %eax, gdtr + 2              # Put address of gdt into the gdtr
        lgdt    gdtr
        movl    $IDT_BASE,%eax              # EAX=PHYSICAL address of idt
        movl    %eax, idtr + 2              # Put address of idt into the idtr
        lidt    idtr
        ret

# VOID
# InstallInterruptHandler (
#     UINTN Vector,
#     VOID  (*Handler)(VOID)
#     )
  ASM_GLOBAL ASM_PFX(InstallInterruptHandler)
ASM_PFX(InstallInterruptHandler):
#  Vector:DWORD @ 4(%esp)
#  Handler:DWORD @ 8(%esp)

        push    %edi
        pushf                               # save eflags
        cli                                 # turn off interrupts
        subl    $6,%esp                     # open some space on the stack
        movl    %esp,%edi
        sidt    (%edi)                      # get fword address of IDT
        movl    2(%edi), %edi               # move offset of IDT into EDI
        addl    $6,%esp                     # correct stack
        movl    12(%esp),%eax               # Get vector number
        shl     $3,%eax                     # multiply by 8 to get offset
        addl    %eax,%edi                   # add to IDT base to get entry
        movl    16(%esp),%eax               # load new address into IDT entry
        movw    %ax,(%edi)                  # write bits 15..0 of offset
        shrl    $16,%eax                    # use ax to copy 31..16 to descriptors
        movw    %ax,6(%edi)                 # write bits 31..16 of offset
        popf                                # restore flags (possible enabling interrupts)
        pop     %edi
        ret

  .macro JmpCommonIdtEntry
    # jmp     commonIdtEntry - this must be hand coded to keep the assembler from
    #                          using a 8 bit reletive jump when the entries are
    #                          within 255 bytes of the common entry.  This must
    #                          be done to maintain the consistency of the size
    #                          of entry points...
    .byte     0xe9                        # jmp 16 bit reletive 
    .long     commonIdtEntry - . - 4      #  offset to jump to
  .endm

    .p2align 1
  ASM_GLOBAL ASM_PFX(SystemExceptionHandler)
ASM_PFX(SystemExceptionHandler):
INT0:
    pushl    $0x0      # push error code place holder on the stack
    pushl    $0x0 
    JmpCommonIdtEntry
#    db      0e9h                        # jmp 16 bit reletive 
#    dd      commonIdtEntry - $ - 4      #  offset to jump to
    
INT1:
    pushl    $0x0      # push error code place holder on the stack
    pushl    $0x1 
    JmpCommonIdtEntry
    
INT2:
    pushl    $0x0      # push error code place holder on the stack
    pushl    $0x2 
    JmpCommonIdtEntry
    
INT3:
    pushl    $0x0      # push error code place holder on the stack
    pushl    $0x3 
    JmpCommonIdtEntry
    
INT4:
    pushl    $0x0      # push error code place holder on the stack
    pushl    $0x4 
    JmpCommonIdtEntry
    
INT5:
    pushl    $0x0      # push error code place holder on the stack
    pushl    $0x5 
    JmpCommonIdtEntry
    
INT6:
    pushl    $0x0      # push error code place holder on the stack
    pushl    $0x6 
    JmpCommonIdtEntry
    
INT7:
    pushl    $0x0      # push error code place holder on the stack
    pushl    $0x7 
    JmpCommonIdtEntry
    
INT8:
#   Double fault causes an error code to be pushed so no phony push necessary
    nop
    nop
    pushl    $0x8 
    JmpCommonIdtEntry
    
INT9:
    pushl    $0x0      # push error code place holder on the stack
    pushl    $0x9 
    JmpCommonIdtEntry
    
INT10:
#   Invalid TSS causes an error code to be pushed so no phony push necessary
    nop
    nop
    pushl    $10
    JmpCommonIdtEntry
    
INT11:
#   Segment Not Present causes an error code to be pushed so no phony push necessary
    nop
    nop
    pushl    $11
    JmpCommonIdtEntry
    
INT12:
#   Stack fault causes an error code to be pushed so no phony push necessary
    nop
    nop
    pushl    $12
    JmpCommonIdtEntry
    
INT13:
#   GP fault causes an error code to be pushed so no phony push necessary
    nop
    nop
    pushl    $13
    JmpCommonIdtEntry
    
INT14:
#   Page fault causes an error code to be pushed so no phony push necessary
    nop
    nop
    pushl    $14
    JmpCommonIdtEntry
    
INT15:
    pushl    $0x0      # push error code place holder on the stack
    pushl    $15
    JmpCommonIdtEntry
    
INT16:
    pushl    $0x0      # push error code place holder on the stack
    pushl    $16
    JmpCommonIdtEntry
    
INT17:
#   Alignment check causes an error code to be pushed so no phony push necessary
    nop
    nop
    pushl    $17
    JmpCommonIdtEntry
    
INT18:
    pushl    $0x0      # push error code place holder on the stack
    pushl    $18
    JmpCommonIdtEntry
    
INT19:
    pushl    $0x0      # push error code place holder on the stack
    pushl    $19
    JmpCommonIdtEntry

INTUnknown:
  # The following segment repeats (32 - 20) times:
  # No. 1
    pushl    $0x0      # push error code place holder on the stack
#    push    xxh     # push vector number
    .byte    0x6a
    .byte    ( . - INTUnknown - 3 ) / 9 + 20 # vector number
    JmpCommonIdtEntry
  # No. 2
    pushl    $0x0      # push error code place holder on the stack
#    push    xxh     # push vector number
    .byte    0x6a
    .byte    ( . - INTUnknown - 3 ) / 9 + 20 # vector number
    JmpCommonIdtEntry
  # No. 3
    pushl    $0x0      # push error code place holder on the stack
#    push    xxh     # push vector number
    .byte    0x6a
    .byte    ( . - INTUnknown - 3 ) / 9 + 20 # vector number
    JmpCommonIdtEntry
  # No. 4
    pushl    $0x0      # push error code place holder on the stack
#    push    xxh     # push vector number
    .byte    0x6a
    .byte    ( . - INTUnknown - 3 ) / 9 + 20 # vector number
    JmpCommonIdtEntry
  # No. 5
    pushl    $0x0      # push error code place holder on the stack
#    push    xxh     # push vector number
    .byte    0x6a
    .byte    ( . - INTUnknown - 3 ) / 9 + 20 # vector number
    JmpCommonIdtEntry
  # No. 6
    pushl    $0x0      # push error code place holder on the stack
#    push    xxh     # push vector number
    .byte    0x6a
    .byte    ( . - INTUnknown - 3 ) / 9 + 20 # vector number
    JmpCommonIdtEntry
  # No. 7
    pushl    $0x0      # push error code place holder on the stack
#    push    xxh     # push vector number
    .byte    0x6a
    .byte    ( . - INTUnknown - 3 ) / 9 + 20 # vector number
    JmpCommonIdtEntry
  # No. 8
    pushl    $0x0      # push error code place holder on the stack
#    push    xxh     # push vector number
    .byte    0x6a
    .byte    ( . - INTUnknown - 3 ) / 9 + 20 # vector number
    JmpCommonIdtEntry
  # No. 9
    pushl    $0x0      # push error code place holder on the stack
#    push    xxh     # push vector number
    .byte    0x6a
    .byte    ( . - INTUnknown - 3 ) / 9 + 20 # vector number
    JmpCommonIdtEntry
  # No. 10
    pushl    $0x0      # push error code place holder on the stack
#    push    xxh     # push vector number
    .byte    0x6a
    .byte    ( . - INTUnknown - 3 ) / 9 + 20 # vector number
    JmpCommonIdtEntry
  # No. 11
    pushl    $0x0      # push error code place holder on the stack
#    push    xxh     # push vector number
    .byte    0x6a
    .byte    ( . - INTUnknown - 3 ) / 9 + 20 # vector number
    JmpCommonIdtEntry
  # No. 12
    pushl    $0x0      # push error code place holder on the stack
#    push    xxh     # push vector number
    .byte    0x6a
    .byte    ( . - INTUnknown - 3 ) / 9 + 20 # vector number
    JmpCommonIdtEntry


  ASM_GLOBAL ASM_PFX(SystemTimerHandler)
ASM_PFX(SystemTimerHandler):
    pushl    $0
    pushl    $ASM_PFX(mTimerVector)
    JmpCommonIdtEntry

commonIdtEntry:
# +---------------------+
# +    EFlags           +
# +---------------------+
# +    CS               +
# +---------------------+
# +    EIP              +
# +---------------------+
# +    Error Code       +
# +---------------------+
# +    Vector Number    +
# +---------------------+
# +    EBP              +
# +---------------------+ <-- EBP

  cli
  push %ebp
  movl %esp,%ebp

  #
  # Align stack to make sure that EFI_FX_SAVE_STATE_IA32 of EFI_SYSTEM_CONTEXT_IA32
  # is 16-byte aligned
  #
  andl    $0xfffffff0,%esp
  subl    $12,%esp

## UINT32  Edi, Esi, Ebp, Esp, Ebx, Edx, Ecx, Eax#
  push    %eax
  push    %ecx
  push    %edx
  push    %ebx
  leal    6*4(%ebp),%ecx
  push    %ecx                          # ESP
  push    (%ebp)                        # EBP
  push    %esi
  push    %edi

## UINT32  Gs, Fs, Es, Ds, Cs, Ss#
  movw  %ss,%ax
  push  %eax
  movzx 4*4(%ebp),%eax
  push %eax
  movw  %ds,%ax
  push %eax
  movw  %es,%ax
  push %eax
  movw %fs,%ax
  push %eax
  movw %gs,%ax
  push %eax

## UINT32  Eip#
  pushl   3*4(%ebp)

## UINT32  Gdtr[2], Idtr[2]#
  subl  $8,%esp
  sidt (%esp)
  subl  $8,%esp
  sgdt (%esp)

## UINT32  Ldtr, Tr#
  xorl  %eax, %eax
  str  %ax
  push %eax
  sldt %eax
  push %eax

## UINT32  EFlags#
  pushl  5*4(%ebp)

## UINT32  Cr0, Cr1, Cr2, Cr3, Cr4#
  mov  %cr4,%eax
  orl  $0x208,%eax
  mov  %eax,%cr4
  push %eax
  mov  %cr3,%eax
  push %eax
  mov  %cr2,%eax
  push %eax
  xor  %eax, %eax
  push %eax
  mov  %cr0,%eax
  push %eax

## UINT32  Dr0, Dr1, Dr2, Dr3, Dr6, Dr7#
  mov     %dr7,%eax
  push    %eax
## clear Dr7 while executing debugger itself
  xor     %eax, %eax
  mov     %eax,%dr7

  mov     %dr6,%eax
  push    %eax
## insure all status bits in dr6 are clear...
  xor     %eax, %eax
  mov     %eax,%dr6

  mov     %dr3,%eax
  push    %eax
  mov     %dr2,%eax
  push    %eax
  mov     %dr1,%eax
  push    %eax
  mov     %dr0,%eax
  push    %eax

## FX_SAVE_STATE_IA32 FxSaveState;
  sub     $512,%esp
  mov     %esp,%edi
  fxsave (%edi)

## UINT32  ExceptionData;
  pushl    2*4(%ebp)

## Prepare parameter and call
  mov     %esp,%edx
  push    %edx
  mov     1*4(%ebp),%eax
  push    %eax
  cmpl    $32,%eax
  jb      CallException
  call    ASM_PFX(TimerHandler)
  jmp     ExceptionDone
CallException:
  call    ASM_PFX(ExceptionHandler)
ExceptionDone:
  addl    $8,%esp

  cli
## UINT32  ExceptionData;
  addl     $4,%esp

## FX_SAVE_STATE_IA32 FxSaveState;
  mov      %esp,%esi
  fxrstor  (%esi)
  addl     $512,%esp

#; UINT32  Dr0, Dr1, Dr2, Dr3, Dr6, Dr7;
  pop     %eax
  mov     %eax,%dr0
  pop     %eax
  mov     %eax,%dr1
  pop     %eax
  mov     %eax,%dr2
  pop     %eax
  mov     %eax,%dr3
## skip restore of dr6.  We cleared dr6 during the context save.
  addl    $4,%esp
  pop     %eax
  mov     %eax,%dr7

## UINT32  Cr0, Cr1, Cr2, Cr3, Cr4;
  pop     %eax
  mov     %eax,%cr0
  addl    $4,%esp    # not for Cr1
  pop     %eax
  mov     %eax,%cr2
  pop     %eax
  mov     %eax,%cr3
  pop     %eax
  mov     %eax,%cr4

## UINT32  EFlags;
  popl     5*4(%ebp)

## UINT32  Ldtr, Tr;
## UINT32  Gdtr[2], Idtr[2];
## Best not let anyone mess with these particular registers...
  addl     $24,%esp

## UINT32  Eip;
  popl     3*4(%ebp)

## UINT32  Gs, Fs, Es, Ds, Cs, Ss;
## NOTE - modified segment registers could hang the debugger...  We
##        could attempt to insulate ourselves against this possibility,
##        but that poses risks as well.
##
  pop     %gs
  pop     %fs
  pop     %es
  pop     %ds
  popl    4*4(%ebp)
  pop     %ss

## UINT32  Edi, Esi, Ebp, Esp, Ebx, Edx, Ecx, Eax;
  pop     %edi
  pop     %esi
  addl    $4,%esp   # not for ebp
  addl    $4,%esp   # not for esp
  pop     %ebx
  pop     %edx
  pop     %ecx
  pop     %eax

  mov     %ebp,%esp
  pop     %ebp
  addl    $8,%esp
  iret


#;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
# data
#;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

  .data
        .p2align 2

gdtr: .short GDT_END - GDT_BASE - 1   # GDT limit
        .long 0                         # (GDT base gets set above)
#;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
#   global descriptor table (GDT)
#;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

        .p2align 2

GDT_BASE:
# null descriptor
NULL_SEL            = .-GDT_BASE
        .short 0            # limit 15:0
        .short 0            # base 15:0
        .byte 0             # base 23:16
        .byte 0             # type
        .byte 0             # limit 19:16, flags
        .byte 0             # base 31:24

# linear data segment descriptor
LINEAR_SEL      = .-GDT_BASE
        .short 0x0FFFF       # limit 0xFFFFF
        .short 0             # base 0
        .byte 0
        .byte 0x092          # present, ring 0, data, expand-up, writable
        .byte 0x0CF          # page-granular, 32-bit
        .byte 0

# linear code segment descriptor
LINEAR_CODE_SEL = .-GDT_BASE
        .short 0x0FFFF       # limit 0xFFFFF
        .short 0             # base 0
        .byte 0
        .byte 0x09A          # present, ring 0, data, expand-up, writable
        .byte 0x0CF          # page-granular, 32-bit
        .byte 0

# system data segment descriptor
SYS_DATA_SEL    = .-GDT_BASE
        .short 0x0FFFF       # limit 0xFFFFF
        .short 0             # base 0
        .byte 0
        .byte 0x092          # present, ring 0, data, expand-up, writable
        .byte 0x0CF          # page-granular, 32-bit
        .byte 0

# system code segment descriptor
SYS_CODE_SEL    = .-GDT_BASE
        .short 0x0FFFF       # limit 0xFFFFF
        .short 0             # base 0
        .byte 0
        .byte 0x09A          # present, ring 0, data, expand-up, writable
        .byte 0x0CF          # page-granular, 32-bit
        .byte 0

# spare segment descriptor
SPARE3_SEL  = .-GDT_BASE
        .short 0            # limit 0xFFFFF
        .short 0            # base 0
        .byte 0
        .byte 0             # present, ring 0, data, expand-up, writable
        .byte 0             # page-granular, 32-bit
        .byte 0

# spare segment descriptor
SPARE4_SEL  = .-GDT_BASE
        .short 0            # limit 0xFFFFF
        .short 0            # base 0
        .byte 0
        .byte 0             # present, ring 0, data, expand-up, writable
        .byte 0             # page-granular, 32-bit
        .byte 0

# spare segment descriptor
SPARE5_SEL  = .-GDT_BASE
        .short 0            # limit 0xFFFFF
        .short 0            # base 0
        .byte 0
        .byte 0             # present, ring 0, data, expand-up, writable
        .byte 0             # page-granular, 32-bit
        .byte 0

GDT_END:

        .p2align 2



idtr: .short IDT_END - IDT_BASE - 1   # IDT limit
        .long 0                         # (IDT base gets set above)
#;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
#   interrupt descriptor table (IDT)
#
#   Note: The hardware IRQ's specified in this table are the normal PC/AT IRQ
#       mappings.  This implementation only uses the system timer and all other
#       IRQs will remain masked.  The descriptors for vectors 33+ are provided
#       for convenience.
#;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

#idt_tag .byte "IDT",0     
        .p2align 2

IDT_BASE:
# divide by zero (INT 0)
DIV_ZERO_SEL        = .-IDT_BASE
        .short 0            # offset 15:0
        .short SYS_CODE_SEL # selector 15:0
        .byte 0             # 0 for interrupt gate
        .byte 0x0e | 0x80   # type = 386 interrupt gate, present
        .short 0            # offset 31:16

# debug exception (INT 1)
DEBUG_EXCEPT_SEL    = .-IDT_BASE
        .short 0            # offset 15:0
        .short SYS_CODE_SEL # selector 15:0
        .byte 0             # 0 for interrupt gate
        .byte 0x0e | 0x80   # type = 386 interrupt gate, present
        .short 0            # offset 31:16

# NMI (INT 2)
NMI_SEL             = .-IDT_BASE
        .short 0            # offset 15:0
        .short SYS_CODE_SEL # selector 15:0
        .byte 0             # 0 for interrupt gate
        .byte 0x0e | 0x80   # type = 386 interrupt gate, present
        .short 0            # offset 31:16

# soft breakpoint (INT 3)
BREAKPOINT_SEL      = .-IDT_BASE
        .short 0            # offset 15:0
        .short SYS_CODE_SEL # selector 15:0
        .byte 0             # 0 for interrupt gate
        .byte 0x0e | 0x80   # type = 386 interrupt gate, present
        .short 0            # offset 31:16

# overflow (INT 4)
OVERFLOW_SEL        = .-IDT_BASE
        .short 0            # offset 15:0
        .short SYS_CODE_SEL # selector 15:0
        .byte 0             # 0 for interrupt gate
        .byte 0x0e | 0x80   # type = 386 interrupt gate, present
        .short 0            # offset 31:16

# bounds check (INT 5)
BOUNDS_CHECK_SEL    = .-IDT_BASE
        .short 0            # offset 15:0
        .short SYS_CODE_SEL # selector 15:0
        .byte 0             # 0 for interrupt gate
        .byte 0x0e | 0x80   # type = 386 interrupt gate, present
        .short 0            # offset 31:16

# invalid opcode (INT 6)
INVALID_OPCODE_SEL  = .-IDT_BASE
        .short 0            # offset 15:0
        .short SYS_CODE_SEL # selector 15:0
        .byte 0             # 0 for interrupt gate
        .byte 0x0e | 0x80   # type = 386 interrupt gate, present
        .short 0            # offset 31:16

# device not available (INT 7)
DEV_NOT_AVAIL_SEL   = .-IDT_BASE
        .short 0            # offset 15:0
        .short SYS_CODE_SEL # selector 15:0
        .byte 0             # 0 for interrupt gate
        .byte 0x0e | 0x80   # type = 386 interrupt gate, present
        .short 0            # offset 31:16

# double fault (INT 8)
DOUBLE_FAULT_SEL    = .-IDT_BASE
        .short 0            # offset 15:0
        .short SYS_CODE_SEL # selector 15:0
        .byte 0             # 0 for interrupt gate
        .byte 0x0e | 0x80   # type = 386 interrupt gate, present
        .short 0            # offset 31:16

# Coprocessor segment overrun - reserved (INT 9)
RSVD_INTR_SEL1      = .-IDT_BASE
        .short 0            # offset 15:0
        .short SYS_CODE_SEL # selector 15:0
        .byte 0             # 0 for interrupt gate
        .byte 0x0e | 0x80   # type = 386 interrupt gate, present
        .short 0            # offset 31:16

# invalid TSS (INT 0ah)
INVALID_TSS_SEL     = .-IDT_BASE
        .short 0            # offset 15:0
        .short SYS_CODE_SEL # selector 15:0
        .byte 0             # 0 for interrupt gate
        .byte 0x0e | 0x80   # type = 386 interrupt gate, present
        .short 0            # offset 31:16

# segment not present (INT 0bh)
SEG_NOT_PRESENT_SEL = .-IDT_BASE
        .short 0            # offset 15:0
        .short SYS_CODE_SEL # selector 15:0
        .byte 0             # 0 for interrupt gate
        .byte 0x0e | 0x80   # type = 386 interrupt gate, present
        .short 0            # offset 31:16

# stack fault (INT 0ch)
STACK_FAULT_SEL     = .-IDT_BASE
        .short 0            # offset 15:0
        .short SYS_CODE_SEL # selector 15:0
        .byte 0             # 0 for interrupt gate
        .byte 0x0e | 0x80   # type = 386 interrupt gate, present
        .short 0            # offset 31:16

# general protection (INT 0dh)
GP_FAULT_SEL        = .-IDT_BASE
        .short 0            # offset 15:0
        .short SYS_CODE_SEL # selector 15:0
        .byte 0             # 0 for interrupt gate
        .byte 0x0e | 0x80   # type = 386 interrupt gate, present
        .short 0            # offset 31:16

# page fault (INT 0eh)
PAGE_FAULT_SEL      = .-IDT_BASE
        .short 0            # offset 15:0
        .short SYS_CODE_SEL # selector 15:0
        .byte 0             # 0 for interrupt gate
        .byte 0x0e | 0x80   # type = 386 interrupt gate, present
        .short 0            # offset 31:16

# Intel reserved - do not use (INT 0fh)
RSVD_INTR_SEL2      = .-IDT_BASE
        .short 0            # offset 15:0
        .short SYS_CODE_SEL # selector 15:0
        .byte 0             # 0 for interrupt gate
        .byte 0x0e | 0x80   # type = 386 interrupt gate, present
        .short 0            # offset 31:16

# floating point error (INT 0x10)
FLT_POINT_ERR_SEL   = .-IDT_BASE
        .short 0            # offset 15:0
        .short SYS_CODE_SEL # selector 15:0
        .byte 0             # 0 for interrupt gate
        .byte 0x0e | 0x80   # type = 386 interrupt gate, present
        .short 0            # offset 31:16

# alignment check (INT 0x11)
ALIGNMENT_CHECK_SEL = .-IDT_BASE
        .short 0            # offset 15:0
        .short SYS_CODE_SEL # selector 15:0
        .byte 0             # 0 for interrupt gate
        .byte 0x0e | 0x80   # (10001110)type = 386 interrupt gate, present
        .short 0            # offset 31:16

# machine check (INT 0x12)
MACHINE_CHECK_SEL   = .-IDT_BASE
        .short 0            # offset 15:0
        .short SYS_CODE_SEL # selector 15:0
        .byte 0             # 0 for interrupt gate
        .byte 0x0e | 0x80   # (10001110)type = 386 interrupt gate, present
        .short 0            # offset 31:16

# SIMD floating-point exception (INT 0x13)
SIMD_EXCEPTION_SEL  = .-IDT_BASE
        .short 0            # offset 15:0
        .short SYS_CODE_SEL # selector 15:0
        .byte 0             # 0 for interrupt gate
        .byte 0x0e | 0x80   # (10001110)type = 386 interrupt gate, present
        .short 0            # offset 31:16

  # The following segment repeats (32 - 20) times:
  # No. 1
        .short 0            # offset 15:0
        .short SYS_CODE_SEL # selector 15:0
        .byte 0             # 0 for interrupt gate
        .byte 0x0e | 0x80   # (10001110)type = 386 interrupt gate, present
        .short 0            # offset 31:16
  # No. 2
        .short 0            # offset 15:0
        .short SYS_CODE_SEL # selector 15:0
        .byte 0             # 0 for interrupt gate
        .byte 0x0e | 0x80   # (10001110)type = 386 interrupt gate, present
        .short 0            # offset 31:16
  # No. 3
        .short 0            # offset 15:0
        .short SYS_CODE_SEL # selector 15:0
        .byte 0             # 0 for interrupt gate
        .byte 0x0e | 0x80   # (10001110)type = 386 interrupt gate, present
        .short 0            # offset 31:16
  # No. 4
        .short 0            # offset 15:0
        .short SYS_CODE_SEL # selector 15:0
        .byte 0             # 0 for interrupt gate
        .byte 0x0e | 0x80   # (10001110)type = 386 interrupt gate, present
        .short 0            # offset 31:16
  # No. 5
        .short 0            # offset 15:0
        .short SYS_CODE_SEL # selector 15:0
        .byte 0             # 0 for interrupt gate
        .byte 0x0e | 0x80   # (10001110)type = 386 interrupt gate, present
        .short 0            # offset 31:16
  # No. 6
        .short 0            # offset 15:0
        .short SYS_CODE_SEL # selector 15:0
        .byte 0             # 0 for interrupt gate
        .byte 0x0e | 0x80   # (10001110)type = 386 interrupt gate, present
        .short 0            # offset 31:16
  # No. 7
        .short 0            # offset 15:0
        .short SYS_CODE_SEL # selector 15:0
        .byte 0             # 0 for interrupt gate
        .byte 0x0e | 0x80   # (10001110)type = 386 interrupt gate, present
        .short 0            # offset 31:16
  # No. 8
        .short 0            # offset 15:0
        .short SYS_CODE_SEL # selector 15:0
        .byte 0             # 0 for interrupt gate
        .byte 0x0e | 0x80   # (10001110)type = 386 interrupt gate, present
        .short 0            # offset 31:16
  # No. 9
        .short 0            # offset 15:0
        .short SYS_CODE_SEL # selector 15:0
        .byte 0             # 0 for interrupt gate
        .byte 0x0e | 0x80   # (10001110)type = 386 interrupt gate, present
        .short 0            # offset 31:16
  # No. 10
        .short 0            # offset 15:0
        .short SYS_CODE_SEL # selector 15:0
        .byte 0             # 0 for interrupt gate
        .byte 0x0e | 0x80   # (10001110)type = 386 interrupt gate, present
        .short 0            # offset 31:16
  # No. 11
        .short 0            # offset 15:0
        .short SYS_CODE_SEL # selector 15:0
        .byte 0             # 0 for interrupt gate
        .byte 0x0e | 0x80   # (10001110)type = 386 interrupt gate, present
        .short 0            # offset 31:16
  # No. 12
        .short 0            # offset 15:0
        .short SYS_CODE_SEL # selector 15:0
        .byte 0             # 0 for interrupt gate
        .byte 0x0e | 0x80   # (10001110)type = 386 interrupt gate, present
        .short 0            # offset 31:16


# 72 unspecified descriptors
  .fill 72 * 8, 1, 0
        
# IRQ 0 (System timer) - (INT 0x68)
IRQ0_SEL            = .-IDT_BASE
        .short 0            # offset 15:0
        .short SYS_CODE_SEL # selector 15:0
        .byte 0             # 0 for interrupt gate
        .byte 0x0e | 0x80   # (10001110)type = 386 interrupt gate, present
        .short 0            # offset 31:16

# IRQ 1 (8042 Keyboard controller) - (INT 0x69)
IRQ1_SEL            = .-IDT_BASE
        .short 0            # offset 15:0
        .short SYS_CODE_SEL # selector 15:0
        .byte 0             # 0 for interrupt gate
        .byte 0x0e | 0x80   # (10001110)type = 386 interrupt gate, present
        .short 0            # offset 31:16

# Reserved - IRQ 2 redirect (IRQ 2) - DO NOT USE!!! - (INT 6ah)
IRQ2_SEL            = .-IDT_BASE
        .short 0            # offset 15:0
        .short SYS_CODE_SEL # selector 15:0
        .byte 0             # 0 for interrupt gate
        .byte 0x0e | 0x80   # (10001110)type = 386 interrupt gate, present
        .short 0            # offset 31:16

# IRQ 3 (COM 2) - (INT 6bh)
IRQ3_SEL            = .-IDT_BASE
        .short 0            # offset 15:0
        .short SYS_CODE_SEL # selector 15:0
        .byte 0             # 0 for interrupt gate
        .byte 0x0e | 0x80   # (10001110)type = 386 interrupt gate, present
        .short 0            # offset 31:16

# IRQ 4 (COM 1) - (INT 6ch)
IRQ4_SEL            = .-IDT_BASE
        .short 0            # offset 15:0
        .short SYS_CODE_SEL # selector 15:0
        .byte 0             # 0 for interrupt gate
        .byte 0x0e | 0x80   # (10001110)type = 386 interrupt gate, present
        .short 0            # offset 31:16

# IRQ 5 (LPT 2) - (INT 6dh)
IRQ5_SEL            = .-IDT_BASE
        .short 0            # offset 15:0
        .short SYS_CODE_SEL # selector 15:0
        .byte 0             # 0 for interrupt gate
        .byte 0x0e | 0x80   # (10001110)type = 386 interrupt gate, present
        .short 0            # offset 31:16

# IRQ 6 (Floppy controller) - (INT 6eh)
IRQ6_SEL            = .-IDT_BASE
        .short 0            # offset 15:0
        .short SYS_CODE_SEL # selector 15:0
        .byte 0             # 0 for interrupt gate
        .byte 0x0e | 0x80   # (10001110)type = 386 interrupt gate, present
        .short 0            # offset 31:16

# IRQ 7 (LPT 1) - (INT 6fh)
IRQ7_SEL            = .-IDT_BASE
        .short 0            # offset 15:0
        .short SYS_CODE_SEL # selector 15:0
        .byte 0             # 0 for interrupt gate
        .byte 0x0e | 0x80   # (10001110)type = 386 interrupt gate, present
        .short 0            # offset 31:16

# IRQ 8 (RTC Alarm) - (INT 0x70)
IRQ8_SEL            = .-IDT_BASE
        .short 0            # offset 15:0
        .short SYS_CODE_SEL # selector 15:0
        .byte 0             # 0 for interrupt gate
        .byte 0x0e | 0x80   # (10001110)type = 386 interrupt gate, present
        .short 0            # offset 31:16

# IRQ 9 - (INT 0x71)
IRQ9_SEL            = .-IDT_BASE
        .short 0            # offset 15:0
        .short SYS_CODE_SEL # selector 15:0
        .byte 0             # 0 for interrupt gate
        .byte 0x0e | 0x80   # (10001110)type = 386 interrupt gate, present
        .short 0            # offset 31:16

# IRQ 10 - (INT 0x72)
IRQ10_SEL            = .-IDT_BASE
        .short 0            # offset 15:0
        .short SYS_CODE_SEL # selector 15:0
        .byte 0             # 0 for interrupt gate
        .byte 0x0e | 0x80   # (10001110)type = 386 interrupt gate, present
        .short 0            # offset 31:16

# IRQ 11 - (INT 0x73)
IRQ11_SEL            = .-IDT_BASE
        .short 0            # offset 15:0
        .short SYS_CODE_SEL # selector 15:0
        .byte 0             # 0 for interrupt gate
        .byte 0x0e | 0x80   # (10001110)type = 386 interrupt gate, present
        .short 0            # offset 31:16

# IRQ 12 (PS/2 mouse) - (INT 0x74)
IRQ12_SEL            = .-IDT_BASE
        .short 0            # offset 15:0
        .short SYS_CODE_SEL # selector 15:0
        .byte 0             # 0 for interrupt gate
        .byte 0x0e | 0x80   # (10001110)type = 386 interrupt gate, present
        .short 0            # offset 31:16

# IRQ 13 (Floating point error) - (INT 0x75)
IRQ13_SEL            = .-IDT_BASE
        .short 0            # offset 15:0
        .short SYS_CODE_SEL # selector 15:0
        .byte 0             # 0 for interrupt gate
        .byte 0x0e | 0x80   # (10001110)type = 386 interrupt gate, present
        .short 0            # offset 31:16

# IRQ 14 (Secondary IDE) - (INT 0x76)
IRQ14_SEL            = .-IDT_BASE
        .short 0            # offset 15:0
        .short SYS_CODE_SEL # selector 15:0
        .byte 0             # 0 for interrupt gate
        .byte 0x0e | 0x80   # (10001110)type = 386 interrupt gate, present
        .short 0            # offset 31:16

# IRQ 15 (Primary IDE) - (INT 0x77)
IRQ15_SEL            = .-IDT_BASE
        .short 0            # offset 15:0
        .short SYS_CODE_SEL # selector 15:0
        .byte 0             # 0 for interrupt gate
        .byte 0x0e | 0x80   # (10001110)type = 386 interrupt gate, present
        .short 0            # offset 31:16

  .fill 1 * 8, 1, 0

IDT_END: