ECEN 350 PRELAB QUIZZES QUESTIONS
Write down the representation of R- and I-format instructions. Explain the purpose of
each field in the instruction.
(fill in the large text box) - Answer -R-Format Instructions: opcode (6 bits), Rm (5 bits),
Shamt (6 bits), Rn (5 bits), Rd (5 bits)
opcode: the operation instruction
Rm: Source register, but the second operand
Shamt: Shift amount
Rn: Source register, but the first operand
Rd: Destination Register
EXAMPLE:ADD X1, X2, X3Translated as: X1 (Rd) = X2 (Rn) + X3 (Rm)
opcode: ADD = 10001011000 in binary
Rm: X3 = 00011 (3 in binary)
Shamt: 0 = 000000
Rn: X2 = 00010 (2 in binary)
Rd: X1 = 00001 (1 in binary)
Put it all together: 10001011000 00011 000000 00010 00001
I-format Instructions: opcode (10 bits), immediate (12 bits), Rn (5 bits), Rd (5 bits)
opcode: the operation instruction
immediate: the constant being added in the instruction
Rn: Source register
Rd: Destination Register
EXAMPLE: ADD X0, X0, #0x64
(Because there is a constant, we are using ADDI)
opcode: ADDI = 1001000100
immediate/"constant": #0x64 (this is in hex) = 000001100100
Rn: X0 = 00000
Rd: X0 = 00000
Put it all together: 1001000100 000001100100 00000 00000
For each of the following instructions, list the instruction format type:
SUB X1, X2, #4:
AND X1, X2, X3:
CBZ:
B:
, LDUR:
STURB:
(note: you will likely want to use the Green Sheet in your book to answer this)
(fill in SIX blanks) - Answer -I
R
CB
B
D
D
Write the binary encoding for the following instructions. Indicate the different fields in the
encoding by placing a space between them.
ADD X3,X2,X5:
ADD X3, X2, #40:
SUB X3,X5, X3:
(fill in THREE blanks) - Answer -10001011000 00101 000000 00010 00011
1001000100 000000101000 00010 00011
11001011000 00011 000000 00101 00011
Translate the following high-level code into assembly language.
Assume variables a − c are held in registers X0 - X2 and f − j are in X19 - X23
a=b-c;f=(g+h)-(i+j);
(fill in the large text box) - Answer -GIVENS:
a = X0; b = X1; c = X2
f = X19; g = X20; h = X21; i = X22; j = X23
SUB X0, X1, X2 (a = b - c)
ADD X1, X20, X21 (b = g + h)
ADD X2, X22, X23 (c = i + j)
SUB X19, X1, X2 (f = b - c)
Write an assembly program to swap the contents of 2 variables stored in registers
X4,and X5. If you need an extra register you may use X1.
(fill in the large text box) - Answer -EOR X1, X4, X5;
EOR X5, X1, X5;
EOR X4, X1, X5;
WORK:
if x1=00001, x4=00100, x5=00101:
Write down the representation of R- and I-format instructions. Explain the purpose of
each field in the instruction.
(fill in the large text box) - Answer -R-Format Instructions: opcode (6 bits), Rm (5 bits),
Shamt (6 bits), Rn (5 bits), Rd (5 bits)
opcode: the operation instruction
Rm: Source register, but the second operand
Shamt: Shift amount
Rn: Source register, but the first operand
Rd: Destination Register
EXAMPLE:ADD X1, X2, X3Translated as: X1 (Rd) = X2 (Rn) + X3 (Rm)
opcode: ADD = 10001011000 in binary
Rm: X3 = 00011 (3 in binary)
Shamt: 0 = 000000
Rn: X2 = 00010 (2 in binary)
Rd: X1 = 00001 (1 in binary)
Put it all together: 10001011000 00011 000000 00010 00001
I-format Instructions: opcode (10 bits), immediate (12 bits), Rn (5 bits), Rd (5 bits)
opcode: the operation instruction
immediate: the constant being added in the instruction
Rn: Source register
Rd: Destination Register
EXAMPLE: ADD X0, X0, #0x64
(Because there is a constant, we are using ADDI)
opcode: ADDI = 1001000100
immediate/"constant": #0x64 (this is in hex) = 000001100100
Rn: X0 = 00000
Rd: X0 = 00000
Put it all together: 1001000100 000001100100 00000 00000
For each of the following instructions, list the instruction format type:
SUB X1, X2, #4:
AND X1, X2, X3:
CBZ:
B:
, LDUR:
STURB:
(note: you will likely want to use the Green Sheet in your book to answer this)
(fill in SIX blanks) - Answer -I
R
CB
B
D
D
Write the binary encoding for the following instructions. Indicate the different fields in the
encoding by placing a space between them.
ADD X3,X2,X5:
ADD X3, X2, #40:
SUB X3,X5, X3:
(fill in THREE blanks) - Answer -10001011000 00101 000000 00010 00011
1001000100 000000101000 00010 00011
11001011000 00011 000000 00101 00011
Translate the following high-level code into assembly language.
Assume variables a − c are held in registers X0 - X2 and f − j are in X19 - X23
a=b-c;f=(g+h)-(i+j);
(fill in the large text box) - Answer -GIVENS:
a = X0; b = X1; c = X2
f = X19; g = X20; h = X21; i = X22; j = X23
SUB X0, X1, X2 (a = b - c)
ADD X1, X20, X21 (b = g + h)
ADD X2, X22, X23 (c = i + j)
SUB X19, X1, X2 (f = b - c)
Write an assembly program to swap the contents of 2 variables stored in registers
X4,and X5. If you need an extra register you may use X1.
(fill in the large text box) - Answer -EOR X1, X4, X5;
EOR X5, X1, X5;
EOR X4, X1, X5;
WORK:
if x1=00001, x4=00100, x5=00101:
