The SPSR stores the current value of the CPSR when an exception is taken so that it can be restored after handling the exception. Each exception handling mode can access its own SPSR. User mode and System mode do not have an SPSR because they are not exception handling modes.
The execution state bits, including the endianness state and
current instruction set state can be accessed from the SPSR in any
exception mode, using the
You cannot access the SPSR using
User or System mode.