Processor with register stack engine that dynamically spills/fills physical registers to backing store

A processor comprising:

• a register file, the register file including a plurality of registers;
• a reserved memory area;
• and
• a unit that:
• allocates a set of registers for [the call of]a function call, the unit saving the contents of certain registers in the reserved memory area when a function is called that requires allocation of a number of registers that exceeds an available number of registers of the register file,
• restores the contents of a set of registers for a function from the reserved memory area to the register file responsive to a recursive call of the function, and
• deallocates the set of registers upon completion of the function.

A method comprising:

• executing an instruction with a processor, the execution of the instruction including making a frame of registers in a register file available to a called procedure;
• stalling the processor in response to an overflow condition, the overflow condition including that a sufficient number of registers are not available in the register file to accommodate the called procedure;
• performing a backing store operation, the backing store operation including saving the contents of one or more registers to a dedicated memory;
• and
• restoring the contents of register from the dedicated memory to the register file, including restoring the contents of a set of registers for a function from the dedicated memory to the register file
• responsive to a recursive call of the function.

A processor comprising:

• a register file comprising a stacked set of physical registers, a frame of registers of the register file being allocated associated with a procedure call, the register file being comprised of a plurality of regions, the plurality of regions including:
• an active region of registers,
• a clean region of registers containing values from a parent frame that have been spilled to memory, and
• a dirty region of registers containing values from a previous frame that have not been spilled to memory;
• and
• a cache dedicated for use as a backing store memory associated with the register file.

A method comprising:

• receiving a code sequence, the code sequence including a plurality of procedure calls;
• calling one of the plurality of procedure calls;
• allocating a first set of registers in response to the called procedure, the first set of registers being a part of a registers file, the register file having a certain size, the procedure call resulting in an overflow condition for the register file;
• saving the contents of a second set of registers in a reserve storage area, the second set of registers being a part of the register file;
• and
• if a recursive procedure call occurs, restoring the contents of a set of register associated with the procedure call from the reserve storage.