Tutorial 7 MODULE 6

Q1 The starting address of a read only valid Non-system data segment in 80286 is C30000H Size is 24KB, Highest Privilege Level, Has been accessed before And addresses have to be incremented to read consecutive data (i.e. address expands upwards) What will be the 8-byte descriptor? (Write from MSB onwards) 10,01,00

Q2 If the 8byte descriptor of a segment in 80286 is 00 00 FF 32 00 00 00 FF What is the size of the segment? Is this a code or data segment? Is this segment Read only/execute only , Read or Write? Has this segment been accessed before? What is the starting address of the segment? What is the minimum RPL required to access this segment? 256 bytes Code Read Yes 32 00 00 11

Q3 Paging is enabled CR3 = 70 00 00 00H Linear address generated is AC 00 01 78H. What will be the address in the Paging Directory that will you look for in order to get the starting address of the paging table? 16KB = 4kx4

Question Processor - 80286 GDTR – 100000H

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 C4 A3 7F 100058 100060 B3 50

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

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

Question 4 DS = 003AH INST – MOV AX,[0200H] Physical Address Type of Segment, Protection Level etc.

Question 5 DS = 0045H LDTR – 00108H MOV BX,[1234H] Physical Address Type of Segment, Protection Level etc.

Processor -80386 CR3 FF 00 00 00 Paging Enabled

GDT Address Data 00100008 00 D0 82 01 FF 00100010 20 00100018 04 Do 83 03 3F 00100020 FC 0A 1F 00100028 DF B0 00100030 92 B1 0F 00100038 B2 7B 00100040 D2 7A 07 00100048 9F A1 00100050 B3 A3 00100058 00100060 30 50

Question 6 DS = 0050H INST – MOV EAX,[00 00 70 34] Physical Address Type of Segment, Protection Level etc.

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

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 03000000 21 00 03000004 22 03000008 23 0300000C 24 03000010 25 03000014 26 03000018 28 0300001C 2A 03000020 2B 03000024 2C 03000028 2D 0300002C 30 Q4 – physical address = A3 12 00 Q5- physical address = B1 12 34 Q6 – linear Address = 00 A3 00 34 Q3- physical address = 10 00 00 34