Comment by wvenable
11 hours ago
As an abstraction on the size of a CPU register, it really turned out to be more confusing than useful.
11 hours ago
As an abstraction on the size of a CPU register, it really turned out to be more confusing than useful.
On RISC machines, it can be very useful to have the concept of "words," because that indicates things about how the computer loads and stores data, as well as the native instruction size. In DSPs and custom hardware, it can indicate the only available datatype.
The land of x86 goes to great pains to eliminate the concept of a word at a silicon cost.
Fortunately we have `register_t` these days.
Is it 32 or 64 bits on ARM64? Why not both?
ARM64 has a 32-bit word, even though the native pointer size and general register size is 64 bits. To access just the lower 32 bits of a register Xn you refer to it as Wn.