5.36 · exercise

Predict: Bitwise Mechanics

Act as the CPU. Trace each shift, mask, and sign-extension snippet and give the exact value it leaves in the destination register.

0 of 4 correct

mov w20, 5
lsl w19, w20, 3

What value does w19 hold after these two instructions? Answer in decimal.

mov w20, -8
lsr w19, w20, 1

What value does w19 hold after the shift? Write it as 0x followed by eight hex digits.

mov x20, 0xFF
mov x21, 0x3C
bic x19, x20, x21

Write the low 8 bits of x19 as eight binary digits, with no prefix.

mov w20, 0xFF
sxtb w19, w20

What value does w19 hold after the sign extension? Write it as 0x followed by eight hex digits.