The document describes the steps taken to execute various CPU instructions on a datapath. It shows the control lines and signals that are activated at each step to fetch operands from registers or memory, perform arithmetic/logical operations, and store results. Common instructions like load, store, move, and add are decomposed into their low-level execution steps on the datapath components like program counter, registers, ALU, memory, and buses.

1.  Nadia Printa Tearani (A11.2010.05214)
 Nur Aji Eka Kharisma (A11.2010.05418)
 Derry Prima (A11.2010.05711)

2.  Operasi-operasi Dasar:
 Mengambil (fetching) Data dari
Memori
 Menyimpan (storing) Data ke
Memori
 Pertukaran Data Antar-Register
 Operasi Aritmatika & Logika di
Datapath

3. Read MFC
Instruksi:
Instruction
LD R2,(R1) ; R2 M[R1] PC
Decoder
Address
lines
MAR IR
Langkah-langkah: Data
lines
1. MAR R1 MDR R1
2. Read Y
3. Tunggu sinyal MFC R2
// MFC = Memory Function Add
Sub
Completed ALU
// Pada saat MFC aktif: XOR
Carry-in
// MDR M[MAR]
Z TEMP
4. R2 MDR

4. Write MFC
Instruksi: PC
Instruction
Decoder
ST (R1),R2 ; M[R1] R2 Address
lines
MAR IR
Data
Langkah-langkah: lines
MDR R1
1. MAR R1 Y
2. MDR R2, Write R2
3. Tunggu sinyal MFC Add
Sub
// MFC = Memory Function ALU
Completed XOR
Carry-in
// Pada saat MFC aktif: Z TEMP
// M[MAR] MDR

5. R1in
Instruksi:
X MOV R4,R1 ; R4 R1
R1
X
R1out Langkah-langkah:
1. Enable output of R1
R4in // setting R1out to 1
X 2. Enable input of R4
R4 // setting R4in to 1
X
R4out

6. Riin
X Instruksi:
Ri ADD R1,R2 ; R1 R1 + R2
X
Riout
Yin Langkah-langkah:
X
Y 1. R1out, Yin
X 2. R2out, Add, Zin
Yout 3. Zout, R1in
A B
ALU
Add X Zin
Z
X
Zout

7. Komponen-komponen Datapath:
 Register: tempat penyimpanan data
 ALU: tempat pemrosesan aritmatika & logika
 Bus: penghubung antar-register & antara register-ALU
Eksekusi Instruksi merupakan kombinasi
pertukaran data antara:
 Register Bus Register
 Register Bus ALU
 Register Bus Memori
Pertukaran data dilakukan dengan cara
mengaktifkan gerbang-gerbang register dengan
menggunakan sinyal-sinyal kendali
(PCout, PCin, dst.)

9. Instruksi:
Add R1,(R3) ; R1 R1 + M[R3]
Langkah-langkah:
1. Fetch instruksi
1. PCout, MARin, Read, Clear Y, Set carry-in to ALU, Add, Zin
2. Zout, PCin, WMFC
3. MDRout, IRin
2. Fetch operand #1 (isi lokasi memori yg ditunjuk oleh
R3)
4. R3out, MARin, Read
5. R1out, Yin, WMFC
3. Lakukan operasi penjumlahan
6. MDRout, Add, Zin
4. Simpan hasil penjumlahan di R1
7. Zout, R1in, End

10. 1. PCout, MARin, Read, Clear Y, Set carry-in to ALU, Add, Zin
2. Zout, PCin, WMFC Control lines
3. MDRout, IRin
Instruction
PC
Decoder
Address
lines
MAR IR
Data
lines
MDR R1
00000000
Y
R3
Add
1
ALU
PC+1 Carry-in
Z TEMP

11. 4. R3out, MARin, Read
5. R1out, Yin, WMFC
Instruction
PC=PC+1
Decoder
Address
lines
MAR IR
Data
lines
MDR R1
Y
R3
ALU
Z TEMP

12. 6. MDRout, Add, Zin
Instruction
PC=PC+1
Decoder
Address
lines
MAR IR
Data
lines
MDR=M[R3] R1
Y=R1
R3
Add
ALU
Carry-in
Zin Z TEMP

13. 7. Zout, R1in, End
Instruction
PC=PC+1
Decoder
Address
lines
MAR IR
Data
lines
MDR=M[R3] R1
Y=R1
R3
ALU
Z=R1+M[R3] TEMP

14. Unconditional (JMP Loop)
1. PCout, MARin, Read, Clear Y, Set carry-in to ALU, Add, Zin
2. Zout, PCin, WMFC
3. MDRout, IRin
4. PCout, Yin
5. Offset-field-of-IRout, Add, Zin // PC PC + Offset
6. Zout, PCin, End
Conditional (contoh: BRNeg Loop)
1. PCout, MARin, Read, Clear Y, Set carry-in to ALU, Add, Zin
2. Zout, PCin, WMFC
3. MDRout, IRin
4. PCout, Yin , If N=0 then End // take the branch?
5. Offset-field-of-IRout, Add, Zin // PC PC + Offset
6. Zout, PCin, End

15. LD Rd,X

16. Instruksi:
LD R16,X ; R16 M[X]
Langkah-langkah:
1. Fetch instruksi
1. PCout, MARin, Read, Clear Y, Set carry-in to ALU, Add, Zin
2. Zout, PCin, WMFC
3. MDRout, IRin
2. Fetch operand dari lokasi memori yang ditunjuk oleh
X
4. Xout, MARin, Read
5. WMFC
3. Lakukan operasi ALU
4. Simpan hasil penjumlahan di R16
6. MDRout, R16in, End

17. 1. PCout, MARin, Read, Clear Y, Set carry-in to
Control lines
ALU, Add, Zin
Read
2. Zout, PCin, WMFC
Instruction
3. MDRout, IRin PC
Decoder
4. Xout, MARin, Read Address
lines
PCout
MAR IR
5. WMFC
MARin
6. MDRout, R16in, End Data
lines
MDR X
Clear Y
00000000
Y
R16
Add
1
ALU
Set
PC+1 Carry-in
Z TEMP
Zin

18. 1. PCout, MARin, Read, Clear Y, Set carry-in to
Control lines
ALU, Add, Zin
WMFC
2. Zout, PCin, WMFC
Instruction
3. MDRout, IRin PC
Decoder
4. Xout, MARin, Read Address
lines
PCin
MAR IR
5. WMFC
6. MDRout, R16in, End Data
lines
MDR X
Y
R16
ALU
Z = PC+1 TEMP
Zout

19. 1. PCout, MARin, Read, Clear Y, Set carry-in to
Control lines
ALU, Add, Zin
2. Zout, PCin, WMFC
Instruction
3. MDRout, IRin PC+1
Decoder
4. Xout, MARin, Read Address
lines
MAR IR
5. WMFC
6. MDRout, R16in, End Data
lines
IRin
MDR X
MDRout
Y
R16
ALU
Z TEMP

20. 1. PCout, MARin, Read, Clear Y, Set carry-in to
Control lines
ALU, Add, Zin
Read
2. Zout, PCin, WMFC
Instruction
3. MDRout, IRin PC+1
Decoder
4. Xout, MARin, Read Address
lines
MAR IR
5. WMFC
6. MDRout, R16in, End Data
lines
MARin
MDR X
Xout
Y
R16
ALU
Z TEMP

21. 1. PCout, MARin, Read, Clear Y, Set carry-in to
Control lines
ALU, Add, Zin
WMFC
2. Zout, PCin, WMFC
Instruction
3. MDRout, IRin PC+1
Decoder
4. Xout, MARin, Read Address
lines
MAR IR
5. WMFC
6. MDRout, R16in, End Data
lines
MDR X
Y
R16
ALU
Z TEMP

22. 1. PCout, MARin, Read, Clear Y, Set carry-in to
Control lines
ALU, Add, Zin
2. Zout, PCin, WMFC
Instruction
3. MDRout, IRin PC+1
Decoder
4. Xout, MARin, Read Address
lines
MAR IR
5. WMFC
6. MDRout, R16in, End Data
lines
MDR X
MDRout
Y
R16
R16in
ALU
Z TEMP

23. ADD Rd,Rs

24. Instruksi:
ADD R16,R17 ; R16 R16 + R17
Langkah-langkah:
1. Fetch instruksi
1. PCout, MARin, Read, Clear Y, Set carry-in to ALU, Add, Zin
2. Zout, PCin, WMFC
3. MDRout, IRin
2. Fetch operand ke-1 (R16)
4. R16out, Yin
3. Fetch operand ke-2 (R17) dan Lakukan operasi ALU
5. R17out, Add, Zin
4. Simpan hasil penjumlahan di R16
6. Zout, R16in, End

25. 1. PCout, MARin, Read, Clear Y, Set carry-in to
Control lines
ALU, Add, Zin
Read
2. Zout, PCin, WMFC
Instruction
3. MDRout, IRin PC
Decoder
4. R16out, Yin Address
lines
PCout
MAR IR
5. R17out, Add, Zin
MARin
6. Zout, R16in, End Data
lines
MDR R17
Clear Y
00000000
Y
R16
Add
1
ALU
Set
PC+1 Carry-in
Z TEMP
Zin

26. 1. PCout, MARin, Read, Clear Y, Set carry-in to
Control lines
ALU, Add, Zin
WMFC
2. Zout, PCin, WMFC
Instruction
3. MDRout, IRin PC
Decoder
4. R16out, Yin Address
lines
PCin
MAR IR
5. R17out, Add, Zin
6. Zout, R16in, End Data
lines
MDR R17
Y
R16
ALU
Z = PC+1 TEMP
Zout

27. 1. PCout, MARin, Read, Clear Y, Set carry-in to
Control lines
ALU, Add, Zin
2. Zout, PCin, WMFC
Instruction
3. MDRout, IRin PC+1
Decoder
4. R16out, Yin Address
lines
MAR IR
5. R17out, Add, Zin
6. Zout, R16in, End Data
lines
IRin
MDR R17
MDRout
Y
R16
ALU
Z TEMP

28. 1. PCout, MARin, Read, Clear Y, Set carry-in to
Control lines
ALU, Add, Zin
2. Zout, PCin, WMFC
Instruction
3. MDRout, IRin PC+1
Decoder
4. R16out, Yin Address
lines
MAR IR
5. R17out, Add, Zin
6. Zout, R16in, End Data
lines
MDR R17
Yin Y
R16
R16out
ALU
Z TEMP

29. 1. PCout, MARin, Read, Clear Y, Set carry-in to
Control lines
ALU, Add, Zin
2. Zout, PCin, WMFC
Instruction
3. MDRout, IRin PC+1
Decoder
4. R16out, Yin Address
lines
MAR IR
5. R17out, Add, Zin
6. Zout, R16in, End Data
lines
MDR R17
R17out
Y=R16
R16
Add
ALU
Zin Z TEMP

30. 1. PCout, MARin, Read, Clear Y, Set carry-in to
Control lines
ALU, Add, Zin
2. Zout, PCin, WMFC
Instruction
3. MDRout, IRin PC+1
Decoder
4. R16out, Yin Address
lines
MAR IR
5. R17out, Add, Zin
6. Zout, R16in, End Data
lines
MDR R17
Y=R16
R16
R16out
ALU
Zout Z=R16+R17 TEMP

31. Peningkatan Kinerja Prosesor

32. A B C
Instruction
Decoder
IR
PC
Register
File
TEMP
ALU
MDR Add R1,R2,R3 ;R1 R2+R3
MAR
Data Address
lines lines
Memory Bus

33. Instruction
PC
Decoder
MAR IR
MDR R1
R2
Y
R3
ALU
Add R1,R2,R3 ;R1 R2+R3
Z TEMP