Abstract: A processor with instructions to operate on different data types stored in a single logical register file. According to one embodiment of the invention, a processor includes a number of physical registers, a memory unit, and a decode/execution unit. The memory unit is to make the number of physical registers appear to software as a single software-visible register file. The decode/execution unit is to execute on the contents of the single software-visible register file instructions of a first instruction type and of a second instruction type, wherein the single software-visible register file is to be operated as a flat register file during execution of instructions of the second instruction type and as a stack referenced register file during execution of instructions of the first instruction type.

Abstract: A processor with instructions to operate on different data types stored in a single logical register file. According to one aspect of the invention, a first set of instructions of a first instruction type operates on the contents of what at least logically appears to software as a single logical register file. The first set of instructions appears to access the single logical register file as a flat register file. In addition, a first instruction of a second instruction type operates on the logical register file. However, the first instruction appears to access the logical register file as a stack referenced register file. Furthermore, sometime between starting the execution of the first set of instructions and completing the execution of the first instruction, all tags in a set of tags indicating whether corresponding registers in the single logical register file are empty or non-empty are caused to indicate non-empty states.

Abstract: A method for executing different sets of instructions that cause a processor to perform different data type operations in a manner that is invisible to various operating system techniques, that promotes good programming practices, and that is invisible to existing software conventions. According to one aspect of the invention, a data processing apparatus executes a first set of instructions of a first instruction type on what at least logically appears to software as a single logical register file. While the data processing apparatus is executing the first set of instructions, the single logical register file appears to be operated as a flat register file. In addition, the data processing apparatus executes a first instruction of a second instruction type using the logical register file. However, while the data processing apparatus is executing the first instruction, the logical register file appears to be operated as a stack referenced register file.

Abstract: A method and apparatus for executing floating point and packed data instructions using a single physical register file that is aliased. According to one aspect of the invention, a processor is provided that includes a decode unit, a mapping unit, and a storage unit. The decode unit is configured to decode instructions and their operands from at least one instruction set including at least a first and second set of instructions. The storage unit includes a physical register file. The mapping unit is configured to map operands used by the first set of instructions to the physical register file in a stack referenced manner. In addition, the mapping unit is configured to map operands used by the second set of instructions to the same physical register file in a non-stack reference manner.