Yes — HL is composed of H as the most significant byte, L as the least. If you perform a 16-bit operation like ADD HL,BC
then carry from the top bit of L+C
will flow into the computation of H+B
. All the register pairs are alike in this regard.
That's because the logical order things are written in isn't related to endianess. E.g. in C you don't have to write 0x0001
on some platforms to equal 0x0100
on others. When writing, you write the most significant first.
The z80 is little endian because if you were to store HL
to memory, L
would be written a byte before H
. If you were to read, L
would be read from the address before H
.