Existing MSP430 byte/word (.b/.w) addressing modes are expanded allowing direct access to 20-bit address (.a) fields which support 1MB (20-bit) program flow and pointer capability. This 20-bit address-word capability is accomplished for program flow, stack manipulation, and pointer handling with the same code density as the 16-bit MSP430 by using un-used bits in the OP codes field. Additionally, an extension word allows full 20-bit addressing for source and destination with any MSP430 instruction and addressing mode and added repetition capability. Finally, cycle counts have been reduced for several addressing modes and interrupt overhead allowing faster code execution.