CENTRAL PROCESSING UNIT HAVING AN X86 AND DSP CORE AND INCLUDING A DSP FUNCTION DECODER WHICH MAPS X86 INSTRUCTIONS TO DSP INSTRUCTIONS

摘要

A CPU or microprocessor which includes a general purpose CPU component, such as an X86 core, and also includes a DSP core. The CPU also includes an intelligent DSP function decoder or preprocessor which examines X86 opcode sequences and determines if a DSP function is being executed. If the DSP function decoder determines that a DSP function is being executed, the DSP function decoder converts or maps the opcodes to a DSP macro instruction that is provided to the DSP core. The DSP core executes one or more DSP instructions to implement the desired DSP function in response to the macro instruction. The DSP core implements or performs the DSP function using a lesser number of instructions and also in reduced number of clock cycles, thus increasing system performance. If the X86 opcodes in the instruction cache or instruction memory do not indicate or are not intended to perform a DSP-type function, the opcodes are provided to the X86 core as which occurs in current prior art computer systems. The X86 core and the DSP core are coupled to each other and communicate data and timing signals for synchronization purposes. Thus, the DSP core offloads these mathematical functions from the X86 core, thereby increasing system performance. The DSP core also operates in parallel with the X86 core, providing further performance benefits. The CPU of the present invention thus implements DSP functions more efficiently than X86 logic while requiring no additional X86 opcodes. The present invention also generates code that operates transparently on an X86 only CPU or a CPU according to the present invention which includes X86 and DSP cores. Thus the present invention is backwards compatible with existing software.