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Tutorial 7 Module 6
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Table for 80286 Processor GDTR – H
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GDT Address Data 100008 00 82 01 FF 100010 20 100018 83 03 3F 100020 FC 0A 1F 100028 DF B0 100030 92 B1 0F 100038 F1 7B 100040 D2 7A 07 100048 9F A1 100050 D4 A3 7F 100058 100060 B3 50
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LDT1 Address Data 010000 00 82 01 FF 010008 20 010010 83 03 3F 010018 FC 0A 1F 010020 DF B0 010028 92 B1 0F 010030 B2 7B 010038 D2 7A 07 010040 9F A1 010048 B3 A3 010050 010058 50
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LDT2 Address Data 200000 00 82 01 FF 200008 20 200010 83 03 3F 200018 FC 0A 1F 200020 DF B0 200028 92 B1 0F 200030 B2 7B 200038 D2 7A 07 200040 A1 200048 B3 A3 200050 200058 50
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Processor CR3 FF Paging Enabled GDTR –
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GDT Address Data 00 D0 82 01 FF 20 04 Do 83 03 3F FC 0A 1F DF B0 92 B1 0F B2 7B D2 7A 07 9F A1 B3 A3 7F 30 50
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PD Address Data FF000000 01 00 FF000004 02 FF000008 03 FF00000C 04
05 FF000014 06 FF000018 08 FF00001C 0A FF000020 0B FF000024 0C FF000028 0E FF00002C 0F
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PT Address Data 030008C0 10 00 030008C4 11 030008C8 12 030008CC 13 030008D0 14 030008D4 15 030008D8 16 030008DC 1A 030008E0 1B 030008E4 1C 030008E8 030008EC Address Data 21 00 22 23 C 24 25 26 28 C 2A 2B 2C 2D C 30 Q4 – physical address = A Q5- physical address = B Q6 – linear Address = 00 A Q3- physical address =
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Descriptor - 80286 0000 0000 Access Rights Base Address B16 – B24
Limit L8 - L15 L0 – L7
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Descriptor - 80386 Base Address B24 – B31 G D AV Limit L16 – L19
AV Limit L16 – L19 Access Rights B16 – B24 B8- B15 B0 – B7 L8 - L15 L0 – L7
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Access rights byte format
P DPL S E ED/C R/W A E ED/C R/W ? Data- Expands Upward – Read Only 1 Data- Expands Upward - Write Data - Expand Downward – Read Only Data- Expand Downward - Write Code – Ignore DPL – Execute Only Code – Ignore DPL – Read allowed Code – Abide DPL – Execute Only Code – Abide DPL – Read allowed
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