5.75 · exercise

Fill in the blank: binary logic

Fill in the missing mnemonic on each line so it performs the bitwise or shift operation described.

0 of 5 correct

Shift the bits in x20 left by 3 so the value in x19 is x20 multiplied by 8.

x19, x20, 3

Clear the bits of x20 that are set in the mask held in x21, leaving the rest untouched.

x19, x20, x21

Copy the whole 64-bit value in x20 into x19 using the alias the assembler encodes as an inclusive OR with the zero register.

x19, x20

Take the low byte of w20 and sign-extend bit 7 across the rest of the 32-bit result in w19.

w19, w20

Shift the signed value in x20 right by 1, copying the sign bit into the vacated high bit.

x19, x20, 1