A method and device for adaptively allocating reservation station entries to an instruction set with variable operands in a microprocessor. The device includes logic for determining free reservation station queue positions in a reservation station. The device allocates an issue queue to an instruction and writes the instruction into the issue queue as an issue queue entry. The device reads an operand corresponding to the instruction from a general purpose register and writes the operand into a reservation station using one of the free reservations station positions as a write address. The device writes each reservation station queue position corresponding to said instruction into said issue queue entry. When the instruction is ready for issue to an execution unit, the device reads out the instruction from the issue queue entry the reservation station queue positions to the execution unit.