Microcontroller instruction set

A microcontroller comprising:

• a central processing unit;
• a data memory having a linearized address space coupled with the central processing unit being divided into n banks;
• the central processing unit comprising:
• a bank select unit which either accesses one of the banks or accesses a virtual bank, whereby the virtual bank combines partial memory space of two banks of the data memory and wherein the selected bank forms a register file;
• an arithmetic logic unit coupled with the register file;
• a plurality of special function registers being mapped to one of the banks in the data memory, wherein one of the special function registers is a working register being coupled with the arithmetic logic unit;
• a program counter register within the central processing unit, the program counter mapped in the data memory;
• and
• a working register within the central processing unit being coupled with the arithmetic logic unit, the working register mapped in the data memory;
• wherein the microcontroller having an instruction set for controlling the arithmetic logic unit and wherein at least one instruction comprises a bit indicating whether the bank select unit accesses one of the banks or the virtual bank.