Abstract: The present invention relates to a system LSI consolidating a logic circuit and an SRAM circuit. More specifically, the present invention relates to a semiconductor device which can reduce a leakage current and the power consumption in the standby state. The logic circuit in the system LSI is provided with a power switch so as to cut off the switch at the time of standby, reducing a leakage current. At the same time, the SRAM circuit controls a substrate bias to reduce the leakage current.

Abstract: A microprocessor comprising a bus state controller and for use in a personal computer or the like. The bus state controller includes control registers such as wait controllers, and parallelly controls the interfaces of various semiconductor memories (ROM, burst ROM, SRAM, PSRAM, DRAM and synchronous RAM) and PC cards (memory and I/O cards). Also included in the bus state controller is a control register for controlling the time to set up PC card start signals where a synchronous DRAM(s) is configured. The address space of an external bus of the microprocessor is divided into a predetermined number of areas to which the semiconductor memories and PC cards are fixedly assigned. The microprocessor further comprises a memory management unit for converting an internally prepared logical address to a physical address.

Abstract: A microprocessor comprising a bus state controller and for use in a personal computer or the like. The bus state controller includes control registers such as wait controllers, and parallelly controls the interfaces of various semiconductor memories (ROM, burst ROM, SRAM, PSRAM, DRAM and synchronous RAM) and PC cards (memory and I/O cards). Also included in the bus state controller is a control register for controlling the time to set up PC card start signals where a synchronous DRAM(s) is configured. The address space of an external bus of the microprocessor is divided into a predetermined number of areas to which the semiconductor memories and PC cards are fixedly assigned. The microprocessor further comprises a memory management unit for converting an internally prepared logical address to a physical address.

Abstract: A microprocessor comprising a bus state controller and for use in a personal computer or the like. The bus state controller includes control registers such as wait controllers, and parallelly controls the interfaces of various semiconductor memories (ROM, burst ROM, SRAM, PSRAM, DRAM and synchronous RAM) and PC cards (memory and I/O cards). Also included in the bus state controller is a control register for controlling the time to set up PC card start signals where a synchronous DRAM(s) is configured. The address space of an external bus of the microprocessor is divided into a predetermined number of areas to which the semiconductor memories and PC cards are fixedly assigned. The microprocessor further comprises a memory management unit for converting an internally prepared logical address to a physical address.

Abstract: The present invention relates to a system LSI consolidating a logic circuit and an SRAM circuit. More specifically, the present invention relates to a semiconductor device which can reduce a leakage current and the power consumption in the standby state.

Abstract: In order to simplify the instruction prefetch architecture for use with the programs having few loops, and having instructions almost in linear and sequential addresses, the bus controller in accordance with the present invention for controlling the bus in an external memory includes a plurality of instruction buffers, flags each specific to each of instruction buffers, and a buffer controller circuit. The buffer controller circuit may allocate one of specific values that plural lower bits of an instruction address may take to each of the instruction buffers, and prefetch instructions to the instruction buffers each corresponding to a respective addresses designated to by the plural lower bits, from the address following a predetermined fetch address. The constitution for instruction prefetch as above may be implemented in a simpler manner than the controlling structure using address tags of a cache memory or the controlling structure using read-write pointer based on the counter in FIFO buffers.

Abstract: In order to simplify the instruction prefetch architecture for use with the programs having few loops, and having instructions almost in linear and sequential addresses, the bus controller in accordance with the present invention for controlling the bus in an external memory includes a plurality of instruction buffers, flags each specific to each of instruction buffers, and a buffer controller circuit. The buffer controller circuit may allocate one of specific values that plural lower bits of an instruction address may take to each of the instruction buffers, and prefetch instructions to the instruction buffers each corresponding to a respective addresses designated to by the plural lower bits, from the address following a predetermined fetch address. The constitution for instruction prefetch as above may be implemented in a simpler manner than the controlling structure using address tags of a cache memory or the controlling structure using read-write pointer based on the counter in FIFO buffers.

Abstract: In order to simplify the instruction prefetch architecture for use with the programs having few loops, and having instructions almost in linear and sequential addresses, the bus controller in accordance with the present invention for controlling the bus in an external memory includes a plurality of instruction buffers, flags each specific to each of instruction buffers, and a buffer controller circuit. The buffer controller circuit may allocate one of specific values that plural lower bits of an instruction address may take to each of the instruction buffers, and prefetch instructions to the instruction buffers each corresponding to a respective addresses designated to by the plural lower bits, from the address following a predetermined fetch address. The constitution for instruction prefetch as above may be implemented in a simpler manner than the controlling structure using address tags of a cache memory or the controlling structure using read-write pointer based on the counter in FIFO buffers.

Abstract: A vector point of an exception handler related to TLB miss exception events is obtained by reading a vector base address of a register VBR one time, and by adding a vector offset (H′400) thereto. A vector point of an exception handler related to exception events other than the TLB miss exception events is obtained by adding a vector offset to a value (vector base address) of the register VBR, and an exception code which is an address offset obtained by reading a value of the register EXPEVT or INTEVT one time is added to the vector point that is obtained. Thus, the processing is branched to a required exception handler to execute the exception event processing related to exception events other than the TLB miss exception events.

Abstract: This data processor can satisfy both requests of a fast transition from a low power consumption state to an operating state and low power consumption, and a data processor has a program running state, a standby mode, a light standby mode, and a sleep mode. In the sleep mode, the supply of a synchronizing clock signal to a central processing unit (CPU) is stopped and the synchronizing clock signal is supplied to other circuit modules. In the standby mode, the frequency multiplication and frequency operation of a clock pulse generator are suspended and the supply of the synchronizing clock signal to the CPU and other circuit modules is stopped. In the light standby mode, the frequency multiplication and frequency division operation of the clock pulse generator are enabled and the supply of the synchronizing clock signal to the CPU and other circuit modules is stopped.

Abstract: A data processor having a debugging aid function capable of monitoring a plurality of kinds of internal buses from the outside and identifying each of the buses monitored is provided. A central processing unit (CPU), a debugging aid module, and other circuit modules are mounted on a semiconductor chip. The debugging aid module selects an information transmitting path in accordance with a trace condition from a plurality of information transmitting paths used for the operation of a central processing unit (CPU) or the like, holds trace information obtained according to the trace condition from the selected information transmitting path together with attribute information of the trace information in a buffer circuit, and outputs the information serially to the outside of the semiconductor chip. A plurality of kinds of internal buses can be monitored on the outside, and each of the buses monitored can be identified.

Abstract: A vector point of an exception handler related to TLB miss exception events is obtained by reading a vector base address of a register VBR one time, and by adding a vector offset (H′400) thereto. A vector point of an exception handler related to exception events other than the TLB miss exception events is obtained by adding a vector offset to a value (vector base address) of the register VBR, and an exception code which is an address offset obtained by reading a value of the register EXPEVT or INTEVT one time is added to the vector point that is obtained. Thus, the processing is branched to a required exception handler to execute the exception event processing related to exception events other than the TLB miss exception events.

Abstract: In order to simplify the instruction prefetch architecture for use with the programs having few loops, and having instructions almost in linear and sequential addresses, the bus controller in accordance with the present invention for controlling the bus in an external memory includes a plurality of instruction buffers, flags each specific to each of instruction buffers, and a buffer controller circuit. The buffer controller circuit may allocate one of specific values that plural lower bits of an instruction address may take to each of the instruction buffers, and prefetch instructions to the instruction buffers each corresponding to a respective addresses designated to by the plural lower bits, from the address following a predetermined fetch address. The constitution for instruction prefetch as above may be implemented in a simpler manner than the controlling structure using address tags of a cache memory or the controlling structure using read-write pointer based on the counter in FIFO buffers.

Abstract: A microprocessor comprising a bus state controller and for use in a personal computer or the like. The bus state controller includes control registers such as wait controllers, and in parallel controls the interfaces of various semiconductor memories (ROM, burst ROM, SRAM, PSRAM, DRAM and synchronous RAM) and PC cards (memory and I/O cards). Also included in the bus state controller is a control register for controlling the time to set up PC card start signals where a synchronous DRAM(s) is configured. The address space of an external bus of the microprocessor is divided into a predetermined number of areas to which the semiconductor memories and PC cards are fixedly assigned. The microprocessor further comprises a memory management unit for converting an internally prepared logical address to a physical address.

Abstract: A vector point of an exception handler related to TLB miss exception events is obtained by reading a vector base address of a register VBR one time, and by adding a vector offset (H'400) thereto. A vector point of an exception handler related to exception events other than the TLB miss exception events is obtained by adding a vector offset to a value (vector base address) of the register VBR, and an exception code which is an address offset obtained by reading a value of the register EXPEVT or INTEVT one time is added to the vector point that is obtained. Thus, the processing is branched to a required exception handler to execute the exception event processing related to exception events other than the TLB miss exception events.

Abstract: A microprocessor comprising a bus state controller and for use in a personal computer or the like. The bus state controller includes control registers such as wait controllers, and in parallel controls the interfaces of various semiconductor memories (ROM, burst ROM, SRAM, PSRAM, DRAM and synchronous RAM) and PC cards (memory and I/O cards). Also included in the bus state controller is a control register for controlling the time to set up PC card start signals where a synchronous DRAM(s) is configured. The address space of an external bus of the microprocessor is divided into a predetermined number of areas to which the semiconductor memories and PC cards are fixedly assigned. The microprocessor further comprises a memory management unit for converting an internally prepared logical address to a physical address.

Abstract: A microprocessor incorporating a PLL circuit using a clock pulse having a relatively low frequency as an input clock signal of a reference frequency to form an oscillating pulse of a relatively high frequency by multiplying the input clock signal. In the microprocessor, the operation of the PLL circuit is stopped in the low-speed mode to supply the clock pulse of the relatively low frequency to the microprocessor as a system clock signal, and, in the high-speed mode, the PLL circuit is activated upon reception of an event requiring high-speed processing. Until the operation of the PLL circuit is stabilized and the request for high-speed processing comes, the above-mentioned clock pulse having the relatively low frequency is kept supplied continuously to the microprocessor as the system clock signal. This novel setup permits the high-speed switching of the microprocessor from the operating mode to the high-speed operating mode.

Abstract: A microprocessor having a buffer or memory capable of holding a plurality of instructions in advance of execution also functions to insert a special bus cycle amongst the instructions for outputting the internal information of the microprocessor to the outside in a predetermined operation mode at the time of each execution. The information inside of the microprocessor, which is to be outputted to the outside in the special bus cycle, is identified by the address of the executed instruction in a memory space, an instruction code or the code for identifying said executed instruction in the instruction group prefetched. In an emulation of the system using the instruction prefetch type microprocessor, as described above, what instruction has been executed can be easily known from the outside to effect an accurate emulation analysis and to facilitate the analysis of trace data thereby to improve debugging efficiency.

Abstract: In a cache memory 20, there exist a plurality of cache lines 201, each of which is equipped with a loop lock L for indicating that an instruction is present in a feedback loop section. The states of the loop locks L are dynamically changed according to the executed state of a program. At the time of excluding the cache lines for a prefetch, the instruction string in the loop is held in the cache memory 20 till the program control transfers to the outside of the loop.

Abstract: The microprocessor has an address converting buffer to convert logical addresses into physical addresses and a signal generator representing the timing for the microprocessor to retrieve conversion information from an external memory and write it into the address converting buffer. With this configuration, it is possible to determine the logical address from the physical address that was output to an external circuit, without the microprocessor outputting the logical address directly to the external circuit.