cbp 2005-6comp 1017 digital technologies1 let’s make a computer … at least the cpu … pentium 4...
TRANSCRIPT
CBP 2005-6 Comp 1017 Digital Technologies 1
Let’s make a Computer
… at least the CPU …
Pentium 4
Pentium 3
Opteron
Ultra Sparc 1
21364Itanium 2 McKinley
CBP 2005-6 Comp 1017 Digital Technologies 2
CBP 2005-6 Comp 1017 Digital Technologies 3
CPU
Memory
Keyboard
VDU
Computer Program (Code)
1 do this
2 do that
3 now this
4 goto 1
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Program Memory
2. High Level Language like ‘C’
3. Assembler Instructions
mov ax,[x]
mov bx,[y]
add ax, bx
mov [w],ax
w = x + y ;
1. Application
Let’s consider a spreadsheet cell which
adds two numbers x + y. This cell and its instruction
is in memory. But it is REPRESENTED in
different ways
Inside the CPU
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Pentium
Data Cache Code Cache
Instruction Fetch
Instruction Decode
Execution Unit
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Minimalist CPU
What do we need to build a CPU?
“Execution Unit”ALU (Arithmetic Logic Unit)
Memory (to store intermediate data)
Input Output
A good Name
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Arithmetic Logic Unit
Input A Input B
Output
ALU
Integer Execution Unit
5
3 2
add 1
3 2
sub
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Input A Input B
Output
ALU
ALU
MMX instructions add bits of images together! Useful for multimedia
Multimedia MMX
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5
3 2
add
0
1
2
3
4
3
2
5
Processing Idea Nr. 1
Move data from memory
Move data into memory3.
2.
1.
Memory DRAM, Hard Disk ..
Move data in and out of data memory store
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5
3 2
add
0
1
2
3
4
3
2
5
Processing Idea Nr.2
IP
(Code Memory)
mov 3 in from memory
mov 2 in from memory
add the two numbers
mov the result to memory
Instruction Memory
Program
Move instructions into CPU from code memory
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Registers
0
1
4
6 8
6
8
4
Registers are high-speed memory on the CPU chip
Parking places for data on the move
AX and BX are used for ALU operations
MAR is memory address register, here 4. So result, 6+8=14 will go into memory cell address 4
AX BX
MAR
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ip
Data Memory
Instruction
Memory
0
1
4
mar
Our computer so far …
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Instruction
Memory
A couple of extra bits
Data Memory
0
1
4
Instruction Register
Memory Data Register 2
8
34
34
2
Data
Address
add ax,bx
1. Line of code goes in
2. Electrical bit signals come out
2.
1.
• Energize ax• Energize bx• Select ALU “add"
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SAM-2
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Moving data into Registers
Instruction
Memory
0
1
2
mar 3
4
mov ax , [1]
85
8
7
6
1
BXAXmov ax , [1] mov bx , [2]mov bx , [2] 7
For example …
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Moving data into Memory
Instruction
Memory
0
1
2
mar 3
4
mov [3] , ax
85
8
7
6
1
BXAXmov [3] , axmov [0], bx
mov [0] , bx 7
For example …
8
7
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Adding Numbers
Instruction
Memory
0
1
2
mar 3
4
add ax , bx
85
7
6
1
BXAXAdd ax,bx
7
For example …
… this means ‘ add ax to bx,
put the answer in ax’8
8 7
15
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I’ve never wrestled with
such a complex
problem before
It must take a lot of organization and control !
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Pentium
Organization and
control
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Fetch-Execute Cycle
1. Fetch instruction from memory
2. Decode the instruction and read any
registers
3. Do any ALU operations (execute units)
5. Write back results to registers
(Organization and Control)
add ax , bx
4. Do any Memory Access
ALU <- ax ALU <- bx
ax + bx
(Data cache)
ax <- ALU
None needed
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add ax , bx
add ax,bx
add ax
0
1
4
3
2
bx
Fetch-Exec : State 1Instruction Fetch
8
3
7
1
9
3 1
AX BX
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0
1
4
3
2
Fetch-Exec : State 2Decode, Register Operations
8
3
7
1
9
add ax , bx
add ax,bx
add ax bx
3 1
3 1
AX BX
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0
1
4
3
2
Fetch-Exec : State 3ALU Operation
8
3
7
1
9
add ax , bx
add ax,bx
add ax bx
AX BX
3 1
4
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0
1
4
3
2
Fetch-Exec : State 4Memory Access
8
3
7
1
9
add ax , bx
add ax,bx
add ax bx
AX BX
3 1
4
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0
1
4
3
2
Fetch-Exec : State 5Register Write
8
3
7
1
9
add ax , bx
add ax,bx
add ax bx
BX
3 1
4
4
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Fetch-Execute Cycle
1. Fetch instruction from memory
2. Decode the instruction and read any
registers
3. Do any ALU operations (execute units)
5. Write back results to registers
(Organization and Control)
mov ax , [1]
4. Do any Memory Access
Read the ‘1’
Put ‘1’ into MAR
Data into ax
Read memory at addr ‘1’
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mov ax , [1]
mov ax , [1]mov ax
0
1
4
3
2
1
Fetch-Exec : State 1Instruction Fetch
8
3
7
1
9
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mov ax , [1]
mov ax , [1]mov ax
0
1
4
3
2
1
Fetch-Exec : State 2Decode, Register Operations
8
3
7
1
9
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mov ax , [1]
mov ax , [1]mov ax
0
1
4
3
2
1
Fetch-Exec : State 3ALU Operation
1
8
3
7
1
9
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mov ax , [1]
mov ax , [1]mov ax
0
1
4
3
2
1
Fetch-Exec : State 4Memory Access
1
8
3
7
1
9
8
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mov ax , [1]
mov ax , [1]mov ax
0
1
4
3
2
1
Fetch-Exec : State 5Register Write
1
8
3
7
1
9
88
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Pentium
5
1
2
3
4
1. Fetch
2. Decode
3. ALU
4. Mem Ops
5. Reg Write
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The first microprocessor
KeypadLots of
ElectronicsLCD Display
Keypad LCD Display
Code Memory
Programmable Electronics
A dedicated design ...
... or a re- usable design
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