Electrical computers and digital processing systems: support – Data processing protection using cryptography – Computer instruction/address encryption
Reexamination Certificate
1999-07-12
2001-05-29
Peeso, Thomas R. (Department: 2132)
Electrical computers and digital processing systems: support
Data processing protection using cryptography
Computer instruction/address encryption
C713S189000, C713S193000, C713S152000, C713S152000
Reexamination Certificate
active
06240516
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a computer system, and more particularly, to a single chip computer system having integrated NPEG and graphical processors.
2. Description of the Related Art
Microprocessors have been used for many years as a primary component of computer systems. Conventionally, a microprocessor is a single chip device that includes a central-processing unit (CPU), registers, I/O and interrupt managers, etc. High performance microprocessors also typically include a built-in coprocessor or a functional unit dedicated to performing floating-point computations.
Recently, graphics and video has become popularized and desirable to many computer users. Specialized graphics support is needed to obtain high quality graphics. Likewise, specialized video support is needed to display moving pictures read from compact-disks or downloaded from a remote server. The existing video compression standard that is often supported is MPEG.
In conventional designs of computer systems that are built to support normal processing as well as graphics and MPEG processing, the hardware or circuitry for all the needed processing is provided by two or more separate integrated circuits. Recently, LSI Logic Corporation of Milpitas, Calif. has produced an integrated circuit chip (Sony-PSx) for Sony Corporation that combined a JPEG like processor and a geometry transformation processor onto a microprocessor chip. However, additional supporting chips were still be required to perform MPEG, display control, and boot-up operations. Also, the interfacing of these supporting chips to the microprocessor chip was very costly in terms of the number of pins required on the microprocessor chip itself. For example, to interface the microprocessor to a MPEG coprocessor would likely require over one-hundred (100) connections (pins) between the microprocessor and the MPEG coprocessor. Having to provide such microprocessor to coprocessor interface is a substantial burden on microprocessor designers and impairs the ability of the microprocessor to support other operations.
Moreover, due to the complexity of the microprocessor and the various coprocessors needed, previously it has been physically impossible or too difficult to combine all the needed functionality into a single integrated circuit chip. As a result, since each of the processors requires significant memory capacity and bandwidth, dedicated memory had to be separately provided in the various chips. The dedicated memories were normally built to handle peak needs of the processor. For example, the memory needs of a microprocessor varies with application size, the memory needs of a graphics processor varies with the size and complexity of the images being rendered, and the memory needs of a MPEG processor varies with picture size. As a result, in conventionalmultimedia computer system designs memory usage was inefficiently utilized. Inefficient usage of memory is problematic because memory is a major cost component of producing such integrated circuits.
Existing microprocessor designs also offer no protection against unauthorized access to program code or data. With multi-chip implementations, an authorized user typically has access to the pins of the chips that interface to the microprocessor and can intercept program code and data therefrom.
Thus, there is a need for a single chip computer system that supports not only normal processing operations but also provides specialized support for graphical and video processing operations. There is also a need for a computer system that provides improved security for program code and data.
SUMMARY OF THE INVENTION
Broadly speaking, the invention relates to a highly integrated, single chip computer system having not only a central-processing unit (CPU) but also specialized coprocessors. The specialized coprocessors, for example, enable the single chip computer system to be reasonably sized, yet perform high quality video and graphics operations. As an example, the video support may be MPEG-2 and the graphics support may handle three-dimensional graphics. The single chip computer system offers improved performance of video and graphics operations, resource scheduling and security. The improved security offered by the single chip computer system enables program code or data stored external to the single chip computer system to be encrypted so as to hinder unauthorized access, while internal to the single chip computer system the program code or data is decrypted. The single chip computer system is particularly suitable for video game consoles having high quality graphics and/or video, digital video disk (DVD) players, and set-top boxes.
The invention may be implemented in numerous ways, including as a system, an apparatus and a method. Several implementations are discussed below.
As a single chip computer system, an embodiment of the invention includes: a read-only memory (ROM), the ROM storing at least boot-up code to boot-up the single chip computer system; a plurality of special-purpose coprocessors for performing special processing tasks; a central processing unit (CPU) for performing general purpose processing tasks, the general purpose processing tasks include executing of program code; at least one inter-processor bus for transmitting data and control signals between the CPU and the coprocessors or between the coprocessors; a memory interface for interfacing the single chip computer system to an external common shared memory; and a main CPU bus for transmitting data and control signals between the CPU and the memory interface. Preferably, the special purpose coprocessors include a graphics geometry coprocessor; a graphics rendering coprocessor; and an MPEG coprocessor.
An embodiment of the single chip computer system may further include: a display controller for controlling a display device to display graphical images and video images; a graphics bus operatively connecting the graphics rendering coprocessor and the memory interface; and a video bus operatively connecting the memory interface to the MPEG coprocessor and the display controller. Still further the single chip computer system may include a stream interface for receiving data from a peripheral drive; a stream bus for supplying the received data to at least one of the inter-processor bus and the main CPU bus; an audio digital-to-analog converter (DAC) interface for operatively connecting the MPEG coprocessor to external speakers; and a video DAC PAL/NTSC encoder for supplying image display information to an external display device in a suitable analog form.
As a single chip computer system that utilizes encrypted program code and data to prevent unauthorized copying of the encrypted program code and data, another embodiment of the invention includes: an internal read-only memory (ROM), the internal ROM storing at least boot-up code to boot-up the single chip computer system and storing a private encryption key; a central processing unit (CPU) for performing general purpose processing tasks, the general purpose processing tasks include executing of program code; a memory interface for interfacing the single chip computer system to an external common shared memory, the memory interface including an encryption/decryption apparatus for encrypting data to be stored to the external common shared memory and for decrypting data retrieved from the external common shared memory, the encryption and decryption being dependent on the private encryption key stored in the internal ROM; and a main CPU bus for transmitting data and control signals between the CPU and the memory interface.
An embodiment of the single chip computer system may further include a plurality of special-purpose coprocessors for performing special processing tasks; and at least one inter-processor bus for transmitting data and control signals between the CPU and the coprocessors or between the coprocessors. Also, the single chip computer system may include a stream interface for receiving encrypted data from a peripheral drive and
Beyer Weaver & Thomas LLP
LSI Logic Corporation
Peeso Thomas R.
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