1. A method comprising: during instruction execution, locating an operand needed by an execution unit by accessing a table, the table tracking operands in a processor pipeline, the table comprising an entry for each of a plurality of general purpose registers, each entry including: an indication of a functional unit port that last wrote to the corresponding general purpose register; an indication of a pipeline stage of the processor pipeline containing an instruction that last wrote to the corresponding general purpose register; and an indication of whether the operand resides in the processor pipeline or an architectural register.