System with wide operand architecture and method

摘要

The present invention provides a system and method for expanding at least one source operand to a width greater than the width of either the general purpose register or the data path width. Operands are provided which are substantially larger than the data path width of the processor. A general purpose register is used to specify a memory address from which at least more than one, but typically several data path widths of data can be read. The data path functional unit is augmented with dedicated storage to which the memory operand is copied on an initial execution of the instruction. Further execution of the instruction or other similar instructions that specify the same memory address can read the dedicated storage to obtain the operand value. However, such reads are subject to conditions to verify that the memory operand has not been altered by intervening instructions. If the memory operand remains current, the memory operand fetch can be combined with one or more register operands in the functional unit, producing a result. The size of the result is, typically, constrained to that of a general register so that no dedicated or other special storage is required for the result.