One embodiment of the present invention provides a system that reduces the time
required to access registers from a register file within a processor. During operation,
the system receives an instruction to be executed, wherein the instruction identifies
at least one operand to be accessed from the register file. Next, the system looks
up the operands in a register pane, wherein the register pane is smaller and faster
than the register file and contains copies of a subset of registers from the register
file. If the lookup is successful, the system retrieves the operands from the register
pane to execute the instruction. Otherwise, if the lookup is not successful, the
system retrieves the operands from the register file, and stores the operands into
the register pane. This triggers the system to reissue the instruction to be executed
again, so that the re-issued instruction retrieves the operands from the register pane.