Abstract: Methods and apparatus are provided for efficiently executing extended custom instructions on a programmable chip. Components of a processor core such as arithmetic logic units, program sequencer units, and address generation units are integrated with customizable logic blocks. Various customizable logic blocks can be invoked in a pipelined manner using an available customized instruction set while allowing a processor to continue simultaneous operation. Program counter snooping is also provided to add custom instruction functionality to a processor with no additional provisions for adding custom instructions.

Abstract: Methods and apparatus are provided for performing circular buffer addressing. Upper boundaries, lower boundaries, circular buffer lengths, addresses, and offsets are set to allow circular buffer access efficiency. An addition/subtraction unit is provided to simplify implementation. Comparators are rearranged and in some instances replaced with combined adder/comparator logic units. The additional logic units and the rearrangement allow efficient implementation of circular buffer addressing, particularly on programmable chips.

Abstract: Methods and apparatus are provided for closely coupling a dedicated memory port to a processor core while allowing external components access to the dedicated memory. A processor core such as a processor core on a programmable chip is provided with dedicated read access to a dual ported memory. Write access is arbitrated between processor core write access and read/write access by external components. A dedicated memory port is particularly beneficial in digital signal processing applications.

Abstract: Methods and apparatus are provided for efficiently implementing a customizable processor core on a programmable chip. Components of a processor core such as arithmetic logic units, program sequencer units, and address generation units are integrated with customizable logic blocks. Various customizable logic blocks can be invoked in a pipelined manner using an available customized instruction set while allowing a processor to continue simultaneous operation. Program counter snooping is also provided to add custom instruction functionality to a processor with no additional provisions for adding custom instructions.