• (-133)*33+44*14.5

133*33+44*14

Input device

memory

calculator

Outputdevice

controller

Control bus

data bus

memory

Chapter 3

Chapter 3

• (-133)*33+44*14.5• Where do we store our data and

code?

• How can we get them?

• Store program and data in memory

• Find them by their addresses

• Addressing mode is based on the architecture of CPU.

Chapter 3:Microprocessor and its

Architecture

• 3.1 Internal Microprocessor Architecture

• 3.2 Real Mode Memory Addressing• 3.3 Protected Mode Memory

Addressing

3.1 Internal Microprocessor Architecture

• 8+6

• MOV AL,8• MOV BL,6• ADD AL,BL

3.1 Internal Microprocessor Architecture

3.1 Internal Microprocessor Architecture

AH AL

BH BL

CH CL

DH DL

SP

BP

DI

SI

AX

BX

CX

DX

SP

BP

DI

SI

Accumulator

Base index

Count

Data

Stack pointer

Base pointer

Destination index

Source index

Multipurpose Registers

DR

PR

IR

16 bits

3.1 Internal Microprocessor Architecture

IP

FLAGS

IP

FLAGS

Instruction pointer

Flags

CS

DS

ES

SS

Code 16bit

Data

Extra

Stack

Special purpose registers

Segment registers

3.1 Internal Microprocessor Architecture

AH AL

BH BL

CH CL

DH DL

SP

BP

DI

SI

EAX

EBX

ECX

EDX

ESP

EBP

EDI

ESI

Accumulator

Base index

Count

Data

Stack pointer

Base pointer

Destination index

Source index

Multipurpose Registers

DR

PR

IR

32 bit

3.1 Internal Microprocessor Architecture

IP

FLAGS

EIP

EFLAGS

Instruction pointer

Flags

CS

DS

ES

SS

FS

GS

Code

Data

Extra

Stack

Special purpose registers

Segment registers

3.1 Internal Microprocessor Architecture

Registers Operations

EAX ADD,SUB,I/O

EBX TRANSFER

ECX CYCLE

EDX MUL,DIV,I/O

EIP Instructor pointer

EBP Base pointer

ESP Stack pointer

3.1 Internal Microprocessor Architecture

EFLAGS C,P,A,Z,I,O……

CS code segment

DS data segment

ES Additional data Segment

SS stack segment

3.1 Internal Microprocessor Architecture

OF

DF

IF

TF

SF

ZF

U AF

U PF

U CF

FLAG of 8086

Undefined CarryParity

Auxiliary

carry

zero

sign

trap

interrupt

direction

overflow

3.2 Real Mode Memory Addressing

3.2 Real Mode Memory Addressing

• We can get those data by their addresses. But how?

• Real mode memory addressing can do that. It can be used in 8086 and above.

3.2 Real Mode Memory Addressing

• Real mode memory addressing

• Physical address = (segment

address)*10H + offset address

Offset address Ranges from 0000H to

FFFFH

8 bit

8 bit

00000H

0FFFFFH

10001H

10002H

• CS =0000H • Offset 0000H, 0FFFFH• CS + offset = 00000H,-----0FFFFH

• CS = 0001H• Offset 0000H, 0FFFFH• CS + offset = 00010H,-----1000FH

• More examples on table 2.1

3.2 Real Mode Memory Addressing

8 bit

8 bit

00000H

0FFFFFH

10001H10002H8 bit

8 bitDATA SEGMENT

CODE SEGMENT

DS = 1000H

CS

3.2 Real Mode Memory Addressing

1FFFF

1F000

10000Segment register 1000

64ka

memory

segment offset F000

00000

+

Physical address 1F000

FFFFF Max PhysicalAddress

is 1M

3.2 Real Mode Memory Addressing

• In real mode the length of memory segment is 64k(FFFFH).

• segment end address = segment start address + FFFFH

3.2 Real Mode Memory Addressing

• The rules of memory addressing define a default combination of segment register and offset register.( 存储段地址和偏移量地址的寄存器有规定的组合方式 ).

3.2 Real Mode Memory Addressing

• Combination is:– CS+IP/EIP locating the next instruction in

code segment

– SS+SP/ESP or SS+BP/EBP locating data in stack segment

– DS+ memory offset locating data in data segment

• The max offset is 64k

3.2 Real Mode Memory Addressing

• Combination is:– When EIP/ESP/EBP is used in an

instruction, only the left 16 bits are available as the offset address whose value is from 0 to 0FFFFH.

– See 2.2.2 paragraph 2.

• The max offset is 64k

3.2 Real Mode Memory Addressing

• Segment and offset addressing scheme allows relocation.

• Move the program to a new area of memory without changing the offset, but only change the contents of the segment registers. Segment start address is allocated by DOS.

3.2 Real Mode Memory Addressing

• Now we have learned about multipurpose registers , special-purpose registers and real mode memory addressing.

00000H

0FFFFFH

1FFFFH

2FFFFH

49000H

58FFFH

MEMMORY 1M

ES

20000H

DS

0FFFFHFigure 2.4

REAL MODE MEMORY ADDRESS

CS

SS

34000H

34FFFH

64K

Figure 2.5

STACK

DATA C

ODE

00000H

0FFFFFH

0A0EFH

0A27FH

0A0F0H

CS

090F0H

DS

0A280H

0A47FH

SS

64K

3.2 Real Mode Memory Addressing

• The max physical address is FFFFFH in real mode memory addressing. So we can only find 1M memory.

• Question : If we have a memory of 128M, how can we get their address in the mode? Are the left 127M disabled?

3.3 Protected Mode Memory Addressing

3.3 Protected Mode Memory Addressing

• Protected mode memory addressing is used in 80286 and above.

• For 80386 and above the max physical address is 4G in this mode.

3.3 Protected Mode Memory Addressing

3.3 Protected Mode Memory Addressing

• See p59 2.6