Complex sentence: IBM defined a set of instructions for a 32-bit microprocessor, as well as designing a set of specifications for the POWER achitecture, both of which used a set of 64-bit and 32-bit instructions.
Split into simpler sentences: IBM defined a set of instructions for a 32-bit microprocessor. IBM made a set of specifications called the POWER Achitecture, which both composed of a set of 64-bit instructions and a set composed of 32-bit instructions.