Steve Ellcey wrote: > OK, I think I understand this a bit better now. I think my main > problem is with the term 'writeback' which I am not used to seeing. > But if I understand things correctly we are saving one or two registers > and (possibly) updating the stack pointer using auto-increment/auto- > decrement in one instruction and that the updating of SP is what you > mean by 'writeback'. Correct?
Correct. The term has been in use since the very first Arm CPUs, where load/stores have a writeback bit to control whether the base register is updated. Note that we don't limit the instructions to simple push/pops: SP is updated by the frame size rather than by the transfer size. Wilco
