Abstract: A method and apparatus for In-System Programming which overcomes the above-described disadvantages. The method and apparatus of the ISP system interfaces with the two oscillator (instead of I/O) pins on the microcontroller. By interfacing with the two oscillator pins, the need for extra isolation circuitry to isolate other circuits from the ISP circuits is avoided in most circumstances, without incurring the expense of an expensive JTAG tester or extra dedicated pins. The amount of isolation circuitry necessary is reduced because the two oscillator pins are usually connected to passive components (registers, capacitors, or crystals) which cannot be damaged by the relatively high programming voltages and which do not produce signals that would interfere with the ISP programming signals.

Abstract: A computer system includes a desk top computer and a portable computer. The desktop computer can be operatively connected to the portable computer and can perform symmetrical processing.

Abstract: A processor for a data-processing system is provided with a dynamically reconfigurable multistage pipeline which permits the execution of more than one instruction set by the processor utilizing the same instruction decoding circuitry and instruction execution control logic circuitry. In one embodiment, the pipeline includes an instruction fetch stage, an instruction conversion stage, an instruction decode stage, and a multiplexer which is used to switch the instruction conversion stage into and out of the pipeline between the instruction fetch stage and the instruction decode stage, even while instructions continue to be executed by the pipeline. The multiplexer operates under control of the instruction decode stage and may be set in response to decoded instructions. The instruction fetch stage is coupled to a bus to retrieve an instruction at a location specified by a program counter.

Abstract: A method and apparatus for providing a programmable logic datapath that may be used in a field programmable device. According to one aspect of the invention, a programmable logic datapath is provided that includes a plurality of logic elements to perform various (Boolean) logic operations. The programmable logic datapath further includes circuitry to selectively route and select operand bits between the plurality of logic elements (operand bits is used hereinafter to refer to input bits, logic operation result bits, etc., that may be generated within the logic datapath). In one embodiment, by providing control bits concurrently with operand bits to routing and selection (e.g., multiplexing) circuitry, the programmable logic datapath of the invention can provide dynamic programmability to perform a number of logic operations on inputs of various lengths on a cycle-by-cycle basis.

Abstract: In a data processing apparatus, a decoding unit decodes instructions. A calculator operates N-bit data in accordance with the decoded results. A flag storage unit stores a plurality of flag groups which are changed in correspondence to data having different widths, based on the operated results. Selectors select a predetermined flag group in accordance with the direction of a conditional branch instruction. A branch judging unit judges whether a branch is taken or not by referring to the selected flag group.

Abstract: In order to reduce a leak current, a processor core unit decodes an instruction fetched by an instruction fetch portion and turns off a leak cut switch for an unused function block of function blocks according to the result of decoding, whereby the supply of power to the corresponding function block is cut off.

Abstract: An integrated buffer controller and data function circuit includes a data function circuit that is controlled by addresses supplied to the circuit. The integrated buffer controller and data function circuit has a bus interface that is used to connect the circuit to a bus on which one or more host adapters are connected so that both the host adapters and a host computer can transfer data to and from the circuit, and supply addresses to control operation of this data function circuit. A data channel in the integrated buffer controller and data function circuit connects the bus interface to a buffer memory controller. The buffer memory controller has a buffer memory port that includes a data port, a memory address port, and a memory control port. A buffer memory is connected to the buffer memory port. A data function circuit in the buffer memory controller is coupled to a data function enable output line.

Abstract: An integrated programmed logic circuit for performing complementary hardware and software based logic functions includes multiple programmed circuit portions. The portion programmed for performing the software based logic functions is programmably configured in a circuit configuration which includes and changes among multiple operation configuration states in accordance with its execution of its instructions. The portion programmed for performing the hardware based logic functions is programmably configured in a circuit configuration which remains in a single operation configuration state prior to, during and subsequent to its processing of data. Hence, the division of processing, i.e., hardware based and software based, can be designed as most appropriate for the particular application, e.g., more hardware based and less software based processing when speed is more important, and more software based and less hardware based processing when processing flexibility is more important.

Abstract: A microprocessor includes an instruction fetch unit, a branch prediction unit, and a decode unit. The instruction fetch unit is adapted to retrieve a plurality of program instructions. The program instructions include serialization initiating instructions and branch instructions. The branch prediction unit is adapted to generate branch predictions for the branch instructions, direct the instruction fetch unit to retrieve the program instructions in an order corresponding to the branch predictions, and redirect the instruction fetch unit based on a branch misprediction. The branch prediction unit is further adapted to store a redirect address corresponding to the branch misprediction. The decode unit is adapted to decode the program instructions into microcode.

Abstract: A data processor such as an integrated circuit microcontroller (10) includes a central processing unit (12), a system integration module (14), and on-chip peripherals (16, 24, 28, 30) commonly connected by an information bus (32). The microcontroller (10) supports transparent background mode operation by not only preserving the state of the central processing unit (12), but also the states of on-chip peripherals (16, 24, 28, 30). For example, a serial peripheral interface (16) has a status register (86) with some status bits which are cleared in normal mode by reading the status register (86). In background mode, reading the status register (86) does not cause the status bits to be cleared. The system integration module (14) has a control bit, known as the break clear flag enable (BCFE) bit, which selectively allows the states of the on-chip peripherals (16, 24, 28, 30) to be altered when the microcontroller is in background mode.

Abstract: A microprocessor has an internal cache memory which can cache a mix of normal system memory and system management mode memory. An address translator passes an address unchanged if a system management mode input signal indicates the normal mode. The address translator translates the address to an address range outside a range of addresses occupied by the external memory when in the system management mode. A cache memory is connected to the address translator for caching data with address tags corresponding to an address received from the address translator. The address translator preferably includes an address range comparator comparing the address with a predetermined address range. The address translation may be combined with virtual memory to physical memory address translation. An inverse address translator handles cache line writeback.

Abstract: A system and method for thermal overload detection and protection for a processor which allows the processor to run at near maximum potential for the vast majority of its execution life. This is effectuated by the provision of circuitry to detect when the processor has exceeded its thermal thresholds and which then causes the processor to automatically reduce the clock rate to a fraction of the nominal clock while execution continues. When the thermal condition has stabilized, the clock may be raised in a stepwise fashion back to the nominal clock rate. Throughout the period of cycling the clock frequency from nominal to minimum and back, the program continues to be executed. Also provided is a queue activity rise time detector and method to control the rate of acceleration of a functional unit from idle to full throttle by a localized stall mechanism at the boundary of each stage in the pipe.

Abstract: In a microprocessor capable of carrying out instructions having different data lengths including an instruction decoder, a register, an operational circuit and a control circuit for controlling the register and the operational unit, the register is divided into a plurality of register units, and the operational circuit is divided into a plurality of operational circuits units, each of which is connected to one of the register units. The control circuit selectively operates the register units and the operation circuit units in accordance with outputs of the instruction decoder.