5.132 · exercise

Predict: bit manipulation

For each snippet, give the exact value left in the named register. The snippets clear, extract, insert, rotate, count and swap bits.

0 of 6 correct

mov w20, 0x2C
sub w21, w20, 1
and w19, w20, w21

What value does w19 hold after the and? Answer in decimal.

mov w20, 0x1234
ubfx w19, w20, 6, 5

What value does w19 hold after the ubfx? Answer in decimal.

mov w20, 0xFFFF
mov w21, 0
bfi w20, w21, 4, 8

Write w20 after the bfi as 0x followed by eight hex digits.

mov w20, 0x5678
movk w20, 0x1234, lsl 16
ror w19, w20, 8

Write w19 after the ror as 0x followed by eight hex digits.

mov x20, 0x100
clz x19, x20

What value does x19 hold after the clz? Answer in decimal.

mov w19, 6
mov w20, 9
eor w19, w19, w20
eor w20, w19, w20
eor w19, w19, w20

What value does w19 hold after the three eor instructions? Answer in decimal.