Cambridge Consultants Limited

Cambridge Silicon Radio Limited

Alistair Guy Morfey

Karl Leighton Swepson

Stephen John Barlow

James Digby Collier

Neil Edward Johnson

Alan Mycroft

Peter Giles Lloyd

Martin David Cooper

Apparatus comprises a processor configured for operation under a sequence of instructions from an instruction set, wherein said processor comprises: means for conditionally inhibiting at least one type of trap, interrupt or exception (TIE) event, wherein, when operating under a sequence of instructions, said inhibition means is inaccessible by said instructions to inhibit the or each type of TIE event, without interrupting said sequence. A data processing apparatus includes a processor adapted to operate under control of program code comprising instructions selected from an instruction set, the apparatus comprising: a predefined memory space providing a predefined addressable memory for storing program code and data, a larger memory space providing a larger addressable memory, means for accessing program code and data within the predefined memory space, and means for controlling the access means so as to enable the access means to access program code located within the larger memory space.

Data processing apparatus with instruction encodings to enable near and far memory access modes

Embodiments of the invention relate to a data processing apparatus including a processor adapted to operate under control of an executable comprising instructions, and in any of a plurality of operating modes including a non-privileged mode and a privileged mode, the apparatus comprising: means for storing a plurality of stacks; a first stack pointer register for storing a pointer to an address in a first of said stacks; a second stack pointer register for storing a pointer to an address in a second of said stacks, wherein said processing apparatus is adapted to use said second stack pointer when said processor is operating in either the non-privileged mode or the privileged mode; and means for transferring operation of said processor from the non-privileged mode to the privileged mode in response to at least one of said instructions. Embodiments of the invention also relate to a method of operating a data processing apparatus.

Data processing apparatus using privileged and non-privileged modes with multiple stacks

A data processing apparatus comprises a processor constructed to operate under control of a sequence of program instructions selected from a predetermined instruction set; master circuitry to request access to storage locations of the processor; an interface circuit to provide an interface for an external apparatus to signal a request for access to the storage locations and an interface for the master circuitry to signal a request for access to the storage locations; and control to provide access between the storage locations and the interface circuit in response to the request only at predetermined points in execution of the stored program, the control being operable to fix periods of time for providing such access relative to the sequence of program instructions such that execution timing of the stored instructions is independent of whether a request is supplied to the interface.

Processor and interface

An integrated circuit contains a microprocessor core, program memory and separate data storage, together with analog and digital signal processing circuitry. The ALU is 16 bits wide, but a 32-bit shift unit is provided, using a pair of 16-bit registers. The processor has a fixed length instruction format, with an instruction set including multiply and divide operations which use the shift unit over several cycles. No interrupts are provided. external pins of the integrated circuit allow for single stepping and other debug operations, and a serial interface (SIF) which allows external communication of test dat or working data as necessary. The serial interface has four wires (SERIN, SEROUT, SERCLK, SERLOADB), allowing handshaking with a master apparatus, and allowing direct access to the memory space of the processor core, without specific program control. Within each processor cycle, the processor circuitry is divided into plural stages, and latches are interposed between the stages to minimize power consumption.

Data processing circuits and interfaces

An integrated circuit contains a microprocessor core, program memory and separate data storage, together with analogue and digital signal processing circuitry. The ALU is 16 bits wide, but a 32-bit shift unit is provided, using a pair of 16-bit registers. The processor has a fixed length instruction format, with an instruction set including multiply and divide operations which use the shift unit over several cycles. No interrupts are provided. External pins of the integrated circuit allow for single stepping and other debug operations, and a serial interface (SIF) which allows external communication of test data or working data as necessary. The serial interface has four wires (SERIN, SEROUT, SER-CLK, SERLOADB), allowing handshaking with a master apparatus, and allowing direct access to the memory space of the processor core, without specific program control. Within each processor cycle, the processor circuitry is divided into plural stages, and latches are interposed between the stages to minimize power consumption.

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Cambridge, United Kingdom

Alistair Guy Morfey