I thought he meant replacing something like
mov memory,%ax
add $1,%ax
mov %ax,memory
with
movzwl memory,%eax
add $1,%eax
mov %ax,memory
or
ldrh r0, [r1]
add r0, r0, #1
strh r0, [r1]
To do that, you need to determine that nothing will read the upper half of %eax. Then the...