Texas Instruments Corporation

Jack Rosenzweig

Gilbert Laurenti

Walter A Jackson

Douglas E Deao

Mark L Buser

Jean-Pierre Giacalone

Shigeshi Abiko

Marc Couvrat

Eric L Badi

Armelle Laine

Herve Catan

Karim Djafarian

Vincent Gillet

Alain Boyadjian

Gael Clave

Jean-Marc Philippe Bachot

Francois Theodorou

Anne Lombardot

Yves Masse

Eric Ponsot

Jean-Louis Tardieux

Laurent Ichard

Emmanuel Ego

Frederic Nidegger

David Russell

N M Ganesh

A processor ( ) is provided that is a programmable fixed point digital signal processor (DSP) with variable instruction length, offering both high code density and easy programming. Architecture and instruction set are optimized for low power consumption and high efficiency execution of DSP algorithms, such as for wireless telephones, as well as pure control tasks. The processor includes an instruction buffer unit ( ), a program flow control unit ( ), an address/data flow unit ( ), a data computation unit ( ), and multiple interconnecting busses. Dual multiply-accumulate blocks improve processing performance. A memory interface unit ( ) provides parallel access to data and instruction memories. The instruction buffer is operable to buffer single and compound instructions pending execution thereof. A decode mechanism is configured to decode instructions from the instruction buffer. The use of compound instructions enables effective use of the bandwidth available within the processor. A soft dual memory instruction can be compiled from separate first and second programmed memory instructions. Instructions can be conditionally executed or repeatedly executed. Bit field processing and various addressing modes, such as circular buffer addressing, further support execution of DSP algorithms. The processor includes a multistage execution pipeline with pipeline protection features. Various functional modules can be separately powered down to conserve power. The processor includes emulation and code debugging facilities with support for cache analysis.

Microprocessors

A processor ( ) is provided that is a programmable digital signal processor (DSP) with variable instruction length. A user stack region ( ) is used to pass variables to a subroutine and to hold values representative of a first portion of a program counter ( ). A system stack region ( ) is used to hold values representative of a remaining portion of the program counter ( ) and to hold additional context information. The user stack region and the system stack region are managed independently so that software from a prior generation processor can be translated to run on processor ( ).

Stack Pointer Management

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Jack Rosenzweig