(1) FETCH = ??? ????? ???????? ?"? ?????? ????? ?-PC.

1
???? ????? ????? ?????

• (1) FETCH ??? ????? ???????? ?"? ?????? ?????
  ?-PC.
• (2) DECODE ???? ?? ?????? ???? ?? ???????
  ??????? (??? ?? ?????).
• (3) EXECUTE ????? ?-ALU ??? ?? ??????, ?? ?????
  ?????.
• (4) MEMORY ????? ?????? ???? ????? ????? ??
  ????? ??????? (Store) ?? ????? ???????? (Load).
• (5) WRITE BACK ??? ????? ????? ????? ?????.

2
???? ?? ????? ????? ?????? ???? ????? ??????
???? ????? - ??????? ?? ?? ?????, ?? ????? ????
???? ???????? ?? ???? ????? (?? ????)
3
MIPS ????? ????? ?? ????
???????? ???????? ?????? ??? ???? ?????? R-type
?- I-type ??? ????? ??????? add, sub, or, xor,
and, slt, lw, sw, beq, j ????? ?????? ???? ????
??????? ?????? ?????? ??? ???? bne, addi, jal,
jr
4
??? ????? ??????
5
????? ?????? ?? ????? ??????? ???? ?-fetch
Instruction
Address
Instruction
Instruction
Memory
Sum
Add
????? ????? ?????? ?????? , ?????? ??????
?????? ??? adder ????? ?????? ????
6
FETCH -??? ?
Add
4
4
PC
Read
address
Instruction
Instruction
memory
7
A CPU capable of R-type instructions only
4
Adder
6
3126
Instruction Memory
PC
6
50funct
8
????? ?????????. ????? ?? ????? ????
?-decode(????? ?-write back)
Read
register
1
Read
data
1
Read
2
????? ???????
register
Registers
Write
Read

register
data
2
Write
Data
Data
9
Arithmetic Logic operation
ALU operation
Read
ALU operation
register
1
Read
data
1
Zero
Read
register
2
Instruction
Registers
ALU
Write
ALU

register
Read
result
data
2
ALU
Write
Data
?????? ??????? ?????? ??? ????? R-type
10
A CPU capable of R-type instructions only
4
Adder
6
3126
Reg File
Instruction Memory
PC
ALU
6
50funct
11
A CPU capable of R-type instructions only
4
Adder
6
3126
Reg File
Instruction Memory
PC
ALU
6
50funct
12
The internal structure of the Register File
Rd reg 1 ( Rs)
32
5
32
32
32
32
Read data 1
write data
32
32
32
Rd reg 2 ( Rt)
5
32
32
32
Read data 2
32
32
Wr reg ( Rd)
5
E
RegWrite
?????? ???? ??????? ??????? ????? ?? ??? ????????
????? ?????? ???? ????????? ?????? (?????? ?????
????)
13
A CPU capable of R-type instructions only
4
Adder
6
3126
RegWrite
Reg File
Instruction Memory
PC
ALU
14
A CPU capable of R-type instructions only
Instruction Memory
Reg File
PC
ALU
15
A CPU capable of R-type instructions only
4
Instruction Memory
Reg File
ALU
PC
16
A CPU capable of R-type instructions only
4
Adder
6
3126
RegWrite
6
50funct
ALU control
Reg File
Instruction Memory
PC
ALU
17
Load,Store ????? ??????
Write
Read
address
Read
data
Write
address
Data
Write
memory
data
Read
??? ???? ?????? ?- data ???? ???? ????? ????? ???
?? ?? ???? sign extension ?? ?- imm ???? ?? 16bit
18
A CPU capable of lw instructions only
4
Adder
6
3126
add
RegWrite1
Reg File
Data Memory
Instruction Memory
PC
ALU
Address
D. Out
5
16
150
Sext 16-gt32
19
A CPU capable of lw instructions only
4
Adder
6
3126
add
RegWrite1
Reg File
Data Memory
Instruction Memory
PC
ALU
Address
D. Out
5
16
150
Sext 16-gt32
20
A CPU capable of lw instructions only
4
Adder
6
3126
add
RegWrite1
Reg File
Data Memory
Instruction Memory
PC
ALU
Address
D. Out
5
16
150
Sext 16-gt32
21
A CPU capable of lw sw instructions only
4
MeWrite1
Adder
6
3126
add
RegWrite0
Reg File
Data Memory
Instruction Memory
PC
ALU
Address
5
D.In
16
150
Sext 16-gt32
22
A CPU capable of R-type lw instructions
(principle)
4
Adder
6
3126
add
RegWrite
6
50funct
ALU control
Reg File
Data Memory
Instruction Memory
PC
ALU
Address
5
16
150
Sext 16-gt32
23
A CPU capable of R-type lw instructions
4
Adder
6
3126
add
RegWrite
6
50funct
ALU control
Reg File
Data Memory
Instruction Memory
PC
ALU
Address
D. Out
5
Rd
16
150
Sext 16-gt32
24
A CPU capable of R-type lw/sw instructions
4
MemWrite
Adder
6
3126
add
RegWrite
6
50funct
ALU control
Reg File
Data Memory
Instruction Memory
PC
ALU
Address
D. Out
5
Rd
D.In
16
150
Sext 16-gt32
25
Branch ??????? ?????? ??????
PC4 ???? ?- Fetch
Adder
In addresses, we always shift left by two bits
Sum
Shift
Branch
Read
left
2
Target
register
1
Read
Read
data
1
register
2
Registers
Write
Instruction
Zero
register

?????
ALU
Read
Write
data
2
??????
Data
?????
??????
16
32
Sigh
??????
Extend
??
???????
26
????? ?? ???????
M
u
x
Add
4
ADD
Write
PC
Read
Zero
data
1
Instruction
Read
ALU
data
2
Data
memory
Read
16
32
27
???? ?- CPU?
Instruction Memory
CPU
PC
Data Memory
28
???? ????
P
C
S
r
c
M
u
Add
A
d
d
x
ALU result
4
Shift left 2
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29
Control
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30
Control
31
ALU control
ALU control output000 AND001 OR010 add110 s
ubtract111 set-on-less-than (sign of rs-rt
-gt rd)
00 lw, sw01 beq, 10 arithmetic
ALUop
32
????? ?- jump
????? ?????? J 101101111011
?????? ???? ????? ?????? 1111110111001
4 bits 26 bits 2 bits
????? ????? ??????
101 101111011
????? ????? ?????
00
101 101111011
0110
101 101111011
????? 4 ????? ???????
00
101 101111011
0110
?????? ??????
33
Jump
S
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2
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2
8
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2
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