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

A processor for running a program that calls multiple functions comprising:

• a register file;
• a reserved memory area;
• and
• a unit that allocates a set of registers for a function call in the program and deallocates the set of registers upon completion of the function, the unit saving a particular set of registers in the reserved area of the memory when a new function is called that requires allocation of a number of registers that exceeds an available number of registers of the register file.

A method of operation for a processor with a register file containing a plurality of registers, comprising the steps of:

• (a) executing an instruction to make a frame of registers available to a called procedure;
• (b) stalling the processor in response to an overflow condition wherein a sufficient number of registers are not available in the register file to accommodate the called procedure;
• and
• (c) performing a backing store operation to a dedicated memory to save registers that overflow the physical register file.

A processor for executing a program that includes procedure calls comprising:

• a register file comprising a stacked set of physical registers, each of the registers being segregated into different regions;
• means for allocating a frame of registers associated with a procedure call;
• a cache dedicated for use as a backing store memory associated with the register file;
• means for spilling/filling the contents of the physical registers between the register file and the cache;
• wherein an active region of registers contains values from a parent frame that have been spilled to the backing store memory, and a dirty region contains values from a previous frame that have not been spilled to the backing store memory.