Question

(12 pts) Suppose r0 = 0xFFFFFFFF, r1 = 0x00000001, r2 = 0x00000000 Initially N, Z, C, V flags are

zero. Find the value of the N, Z, C, V flags of the following instructions. (Assume each instruction

runs individually, i.e. these instructions are not part of a program.). Hint: This time remember

what the default flag are values for the N, Z, C, V flags. The default flag values might vary based

on the flag type.

• ADD r3, r0, r2

• SUBS r3, r0, r0

• ADDS r3, r0, r2

• LSL r3, r0, #1

4. (12 pts) Suppose r0 = 0x0F0F0F0F, and r1 = 0xFEDCBA98, find the result of the following

operations.

• ORR r3, r1, r0

• AND r3, r1, r0

• BFI r3, r1, #4, #8

• MVN r3, r1

ADD r3, r1, r3

Answer 1

(1) ADD r3,r0,r2 will perform the addition of r0 and r2 and store the result in r3.

the value of r3=0xFFFFFFFF. (N,Z,C,V are zero since the result is not negative,not zero,no carry and no overflow)

SUBS r3,r0,r0 performs the substraction of r0-r0 and store the result in r3 and the flags are updated.

r3= 0x00000000 (N=0,Z=1 since the result is zero,C=0 and V=0)

ADDS r3,r0,r2 will perform the addition of r0 and r2 and store the result in r3 and the flags are updated.

r3=0xFFFFFFFF. (N,Z,C,V are zero)

LSL r3, r0, #1 performs the Logical Left shift operation by 1 bit with flag update.

r3=0xFFFFFFFE( N,Z,C,V flags are zero)

(2) ORR r3, r1, r0 performs r1 OR r0 and store the result in r3.

r3= 0xFFDFBF9F

AND r3, r1, r0 performs r1 AND r0 and store the result in r3.

r3= 0x0E0C0A08

BFI r3, r1, #4, #8 performs bit field insert.

Replace bit 4 to bit 11 of r3 with bit 0 to bit 7 of r1.

r3=0xFFFFF98F

MVN r3, r1 performs the operation of writing bitwise inverse of r1 to r3.

r3=0x01234567

ADD r3, r1, r3 perform the addition of r1 and r3 and store the result in r3. Here value of r3 is taking as 0x01234567.

r3=0xFFFFFFFF

Calculations are attaching here as an image.