ECE 252 mindless meorization

Question 1

Flags tested for EQ

Answer 1

Z=1

Question 2

Flags tested for NE

Answer 2

Z=0

Question 3

Flags tested for GT

Answer 3

Z=0 & N=V

Question 4

Flags tested for GE

Answer 4

N=V

Question 5

Flags tested for LT

Answer 5

N!=V

Question 6

Flags tested for LE

Answer 6

Z=1 or N!=V

Question 7

3 tests for equivalence

Answer 7

CMP, TEQ, SUBS

Question 8

Instructions for DCD

Answer 8

LDR, STR

Question 9

Instructions for DCB

Answer 9

LDRB, LDRSB, STRB

Question 10

Instructions for DCW

Answer 10

LDRH, LDRSH, STRH

Question 11

What is the Q flag used for?

Answer 11

If a number is saturated. For instance, if a number tested in SSAT or USAT is out of bounds, Q=1.

Question 12

What is ASR used for?

Answer 12

Division by 2^n

Question 13

What is LSL used for?

Answer 13

Multiplication by 2^n

Question 14

What is the carry flag used for?

Answer 14

In addition, it is set to 1 if there is a carry. In subtraction, it is set to 0 if there is a borrow, or 1 otherwise.

Question 15

What flags do logical operations (AND/OR) touch?

Answer 15

N and Z

Question 16

What is the range representable by 2’s compliment?

Answer 16

-2^(n-1) to 2^(n-1)-1

Question 17

What does REV do?

Answer 17

Reverse the byte order in a word. The the last byte becomes the first byte and so on.

Question 18

What does REV16 do?

Answer 18

Reverse the byte order of the two half words

Question 19

What does SX usually mean?

Answer 19

Something is done and a negative sign extension is applied.

Question 20

How is a rotate left done?

Answer 20

Do a ROR with 32-the desired shift to the left.