COE121 Q3 FE Reviewer
MOV DX,[BX+04]
.Based addressing mode example
Segment address
.It defines the beginning address of any 64k-byte memory segment.
4GB
32-bit microprocessors operating in protected mode could address up to ______ of memory.
20-bit
80286 could be operated in protected mode but with only have _____ for address bus
20-bit
A processor running in real-mode is limited to use _____ of its address bus to access the memory system
Based addressing mode
A type of addressing mode, the offset address of the operand is given by the sum of contents of the BX/BP registers and 8-bit/16-bit displacement.
Effective Addressing
Address is referred to _____ when the processor's address bus is formed by some combination of segment register and an additional numerical offset.
Immediate addressing
An addressing form in which the data to be used or retrieved in the instruction, is located immediately after the opcode of the instruction.
ADD AL,[DI+16]
An example of indexed addressing mode
MOV ECX,EAX
An example of register addressing mode
MOV SI,[BX+04]
An example of register-relative addressing mode
21000H
Given CS = 2000H and IP = 1000H, find the memory address of the next instruction executed by the microprocessor.
Writes byte of data from BH into memory location 1000H
If SI = 1000H, what does MOV [SI],BH do?
Register relative addressing mode
In this addressing mode, the data in a segment of memory are addressed by adding the displacement to the contents of a base or an index register (BP, BX, DI, or SI)
Indexed addressing mode
In this addressing mode, the operands offset address is found by adding the contents of SI or DI register and 8-bit/16-bit displacements.
Register Indirect Addressing Mode
It transfers a byte or word between a register and a memory location addressed by an index or base register.
Base-plus-index
MOV AX,[BX+4] is a sample of which type of addressing?
Register indirect
MOV DL,[SI] is a sample of which type of addressing mode?
They should only contain segment addresses
One must never use the segment registers as data registers to hold arbitrary values because:
A global descriptor table
TI = 0 indicates that TI is _____
Real
The DOS operating system requires the microprocessor to operate in _____ mode
Direct Mode
The addressing mode in which the effective address of the memory location is visibly part of the instruction.
d. Both b and c
The first 1Mb of memory is called the _____ memory system a. Unreal mode b. Conventional c. Real mode d. Both b and c
Has mixed sizes operands
The instruction MOV DS:[2000H], AL
16 bytes
The minimum distance possible between two overlapping 64-kB memory segments is
AE98D
The physical address accessed by segment offset combination A359:B3FD
Direct
This addressing mode moves a byte or word between a memory location and a register.
Indirect
This addressing mode uses a register to hold the actual address that identifies either the source or the destination to be used in the data move.
MOV AX,[BX]
This is an example of Register Indirect Addressing Mode.
4455FH
What is the ending address of a memory segment if the segment register contains 3456H?
10000H, 1FFFFH
What is the starting and ending address of the segment 1000H?
d. Both a and b
Which addressing mode executes its instruction within CPU without the need to access the memory? a. Direct b. Immediate c. Indirect d. Both a and b
RPL > DPL
Which of the following conditions allow access to the segment?
MOV CL,[BX-DI+2]
Which of the following examples is a Based Indexed with displacement addressing mode?
MOV [500H],AL
Which of the following examples is a direct addressing mode?
MOV AL,FFH
Which of the following examples is an Immediate Addressing Mode?
c. Both of the above
Which of the following is an example of Relative program addressing? a. JMP [2] b. JMP [0123] c. Both of the above
a, c, and d
Which of the following segment offset combinations points to a common physical memory address? a.) A1B2:000C, b.) A1B0:200C, c.) A1B0:002C, d.) A1B1:001C
