Date: 11 Apr 2013

General purpose registers (GPR) are not used for storing any specific type of information. Instead operands as well as addresses are stored at the time of program execution. However the operand and the address information may not be of the same size. For example, in 8-bit microprocessors, the data is 8 bit whereas the address is 16 bit.

To allow storage of both types of information, provision is usually made to access registers individually with bit size, say, k or as register pairs where the registers are concatenated to provide bit size of 2 k as shown in the following figure.