1. A method for executing computer processes comprising: pushing execution items of a first class of execution items on a first stack data structure, storing execution items of a second class of execution items in a second stack data structure, the second stack data structure comprising an inverse stack data structure, and applying said execution items to an instruction execution unit by: selectively popping said execution items of said first class from said first data structure, and selectively reading said execution items of said second class from said second stack data structure.