2-2 Operation Modes and CPU Internal Registers We will describe the internal registers of the SH-3’s CPU. There are 16 general, control and system registers in the CPU. The 8 general registers are configured in 2 banks, to reduce register save/restore and to shorten the time for responding to interrupts. The registers that can be used vary depending on the operating mode.These CPU internal registers can be used immediately following reset. Bank 1 is used for general registers. In user mode the number of registers that can be used is reduced. Bank 0 is used for general registers. It is also possible to change Bank 1 to Bank 0 for general registers in privileged mode.