1. Question 0: Register Files
Complete the register transfer operations listed below implemented by the given register file AA BA DA WR RD
Operation 01 10 00 1 11 1 1

2. Answer Questions 1,2 and 3 using the following 16-bit Instruction Formats
Opcode
Operands
Function
ADD RD,RA,RB RD RA RB
R[DR]←R[SA]+R[SB]
SUB RD,RA,RB
R[DR]←R[SA]-R[SB]
DCR RD,RA
xxx
R[DR]←R[SA] -1
INC RD,RA
R[DR]←R[SA] +1
AND RD,RA,RB
R[DR]←R[SA]  R[SB]
OR RD,RA,RB
R[DR]←R[SA]  R[SB]
MOV RD,RA
R[DR]←R[SA]
ST RD,offset(RA)
Oper
M[R[SA]+Oper] ← R[SB]
LD RD,offset(RA)
Oper.
R[DR]←M[R[SA]+Oper]
LDI RD,operand RD
OperH
OperL
R[DR]←se || Operand
ADI RD,RA,operand RA
Oper.
R[DR]←R[SA] + se || Operand
SUI.U RD,RA,operand
R[DR]←R[SA] - zf || Operand
BZ offset
Address Offset
If R[SA]=0 GOTO [PC+offset]
BNZ offset
If R[SA]≠0 GOTO [PC+offset]
JMP offset
GOTO [PC+offset]

3. Question 1
What is the range of numbers that can be used by the signed arithmetic operations (such as ADI R3,R2,N)?
What is the range of numbers that can be used by the unsigned arithmetic operations (such as ADI.U R3,R2,N)?
What is the range of numbers that can be loaded in a register using the LDI instruction?
What is the range of numbers that can be loaded in a register using the LDI.U instruction?
What is the maximum number of bits by a which a number can be shifted?
What is the maximum forward displacement (Distance between current to next instruction) of a conditional branch instruction?
What is the maximum backward displacement (Distance between current to next instruction) of a conditional branch instruction?
What is the maximum size of data memory supported by the proposed ISA?
Write a sequence of instructions that can implement the C-instructions “short int x=-101;” and “unsigned short int y = 132;”. Use register R0 as a data memory pointer initialized to the address 0x90, and that the address of x is 0x92 and the address of y is 0x95. Assume that the size of all registers and “short int” is 8 bits.

4. Q2. Determine the machine codes for the following program
Assembly
Opcode Operands
Address
m/c Codes
LDI R2,26
0100
LDI R4,-18
ST R1,1(R2)
L0:
LD R3,2(R1)
MOV R5,R2
SUB R4,R5,R2
BZ L2 L1
INC R4,R3
LD R2,3(R1)
BNZ L3
BZ L1
L2:
SUI R4,R2,3
INC R2,R4
ADD R4,R2,R2
JMP L0
L3:
ST R1,2(R4)

5. Q3. Disassembly the following program
Address
m/c Code
Opcode Operands
Assembly
100
0EA8
L0:
102
06D0
L1:
104
E212
L2:
106
0170
L3:
108
E1F6
L4:
10A
23B3
L5:
10C
131A
L6:
10E
A023
L7:
110
0120
L8:
112
A063
L9:
114
0248
L10:
116
E3EE
L11:
118
C062
L12:
11A
F1E6
L13:

6. For the next three questions consider the following datapath

7. Control Word to Micro-operation Examples
Determine the microoperation for the following control words:
Control Word DA AA BA MB
FS3..0 MD RW
Micro-operation
6C11
E215
36A1
4801
D5C0
2143
3975
2545
3CDD

8. Micro-operation to Control Word Examples
Determine the control word for the following microoperations:
Micro-operation DA AA BA MB
FS4..0 MD RW
Control Word
R1  R2 - R5
R6  DCR(R7)
R4  R5 + 3
R1  R2 xor R3
R2  Data In=M[R5+2]
M[R2+1]  Dout = R3
R3  LSL (R5,2)
R2  -6
R6  R1-R4-Cy
R5  - (R3)

9. Control Word to Micro-operation Examples
Determine the microoperation and the content of the destination register location after the sequence of the following control words is applied to the datapath.
Assume that the initial values of the registers and memory are as shown Assume also that the control words are applied sequentially on the datapath
Reg.
Data
Addr. R0 3C 88 35 R1 24 89 65 R2 6A 8A A4 R3 58 8B 4C R4 8C R5 10 8D 33 R6 C9 8E 98 R7 1F 8F 1A 90 2C 91 F1 92 3E 93 50 94 3A 95 77 96 97 45
C.Word DA AA BA MB
FS3..0 MD RW
Micro-op.
Result
0F01
5143
66E5
F1C0
B975
C605
E419