Abstract: A MOD_SAT instruction indicating that a 16 bit saturation is to be carried out with respect to the operation of one of instructions executed in parallel is placed in the left container and an ADD instruction is placed in the right container. When the instruction decode unit decodes these instructions, the instruction decode unit indicates that the instruction execution unit executes the ADD instruction accompanying a saturation process. Accordingly, the operation of a great number of instructions can be modified by combining instructions and, therefore, the basic instruction length can be made short and it becomes possible to increase the code efficiency.

Abstract: A MOD_SAT instruction indicating that a 16 bit saturation is to be carried out with respect to the operation of one of instructions executed in parallel is placed in the left container and an ADD instruction is placed in the right container. When the instruction decode unit decodes these instructions, the instruction decode unit indicates that the instruction execution unit executes the ADD instruction accompanying a saturation process. Accordingly, the operation of a great number of instructions can be modified by combining instructions and, therefore, the basic instruction length can be made short and it becomes possible to increase the code efficiency.

Abstract: A data processor, and particularly in a data processor performing condition execution on the basis of flag information, aims at obtaining a data processor having excellent code efficiency, which can reduce branch penalty. In order to attain the aforementioned object, it is so structured that, when a first instruction decoded in a first decoder is an execution condition specifying instruction specifying the execution condition for a pair of second instructions executed in parallel, a first execution condition determination unit performs determination of the execution condition for the second instructions defined by the execution condition specifying instruction on the basis of the flag information and controls assertion/non-assertion of an execution inhibit signal on the basis of whether the execution condition defined by the execution condition specifying instruction is satisfied or not.

Abstract: A comparator 172 compares the value held in an RPT_B register 171 with the address of the instruction which is held in an IA register 181 and is to be fetched next, and outputs coincidence information indicating whether these value coincide with each other. Based on the coincidence information, a control part 112 generates hardware-wise a control signal for switching an instruction processing sequence to the next instruction of a repeat block in the last repeat processing of the repeat block.

Abstract: An input pointer update circuit updates an input pointer in response to the value of an RBC latch, the input pointer of a BIP latch and input pointer update information from an instruction decoding unit (first decoder) when the value of an RM latch is “1”. An output pointer update circuit updates an output pointer in response to the value of the RBC latch, the output pointer of a BOP latch and output pointer update information from the instruction decoding unit (the first decoder or a second decoder). A register mapping circuit maps a logical register number to a physical register number on the basis of output information from the input pointer update circuit, the output pointer update circuit etc.

Abstract: A data processor can assign a greater number of operations to instruction codes with shorter length, thereby implementing high performance, high code efficiency and low cost data processor. The data processor is a VLIW (Very Long Instruction Word) system that can execute a plurality of operations in parallel, and specify the execution sequence of the operations. It can assign a plurality of operations to the same operation code, and the operations that are executed in a second or subsequent sequence are limited to only predetermined operations among the plurality of operations.

Abstract: A MOD_SAT instruction indicating that a 16 bit saturation is to be carried out with respect to the operation of one of instructions executed in parallel is placed in the left container and an ADD instruction is placed in the right container. When the instruction decode unit decodes these instructions, the instruction decode unit indicates that the instruction execution unit executes the ADD instruction accompanying a saturation process. Accordingly, the operation of a great number of instructions can be modified by combining instructions and, therefore, the basic instruction length can be made short and it becomes possible to increase the code efficiency.

Abstract: The present invention relates to a data processor, and particularly in a data processor performing condition execution on the basis of flag information, aims at obtaining a data processor having excellent code efficiency, which can reduce branch penalty.

Abstract: The present invention relates to a data processor, and particularly in a data processor performing condition execution on the basis of flag information, aims at obtaining a data processor having excellent code efficiency, which can reduce branch penalty. In order to attain the aforementioned object, it is so structured that, when a first instruction decoded in a first decoder is an execution condition specifying instruction specifying the execution condition for a pair of second instructions executed in parallel, a first execution condition determination unit performs determination of the execution condition for the second instructions defined by the execution condition specifying instruction on the basis of the flag information and controls assertion/non-assertion of an execution inhibit signal on the basis of whether the execution condition defined by the execution condition specifying instruction is satisfied or not.

Abstract: A comparator 172 compares the value held in an RPT_B register 171 with the address of the instruction which is held in an IA register 181 and is to be fetched next, and outputs coincidence information indicating whether these value coincide with each other. Based on the coincidence information, a control part 112 generates hardware-wise a control signal for switching an instruction processing sequence to the next instruction of a repeat block in the last repeat processing of the repeat block.

Abstract: A data processor can assign a greater number of operations to instruction codes with shorter length, thereby implementing high performance, high code efficiency and low cost data processor. The data processor is a VLIW (Very Long Instruction Word) system that can execute a plurality of operations in parallel, and specify the execution sequence of the operations. It can assign a plurality of operations to the same operation code, and the operations that are executed in a second or subsequent sequence are limited to only predetermined operations among the plurality of operations.

Abstract: A data processor in accordance with the present invention makes it possible to perform pre-branch processing with respect to a return address in the initial stage of pipeline processing also on a subroutine return instruction, and therefore by providing a stack memory (PC stack) dedicated to a program counter (PC) for storing only return addresses of the subroutine return instruction, in executing a subroutine call instruction in an execution stage of a pipeline processing mechanism, the return address from the subroutine is pushed to the PC stack, and the pre-branch processing is performed to the address popped from the PC stack in decoding the subroutine return instruction in an instruction decoding stage.

Abstract: A data processor comprises an instruction decoding unit having two decoders decoding respective instructions of an instruction group consisting of a plurality of instructions including a first instruction and a second instruction succeeding the first instruction, and a judging unit judging whether or not a combination of the first instruction and the second instruction can be executed in parallel and a bus for transferring two data in parallel between an operand access unit and an integer operation unit. The data processor uses a superscalar technique. Two instructions having an operand interference can be executed in parallel at high speed and two instructions accessing a memory can be executed in parallel without considerable hardware.

Abstract: A data processor in accordance with the present invention makes it possible to perform pre-branch processing with respect to a return address in the initial stage of pipeline processing also on a subroutine return instruction, and therefore by providing a stack memory (PC stack) dedicated to a program counter (PC) for storing only return addresses of the subroutine return instruction, in executing a subroutine call instruction in an execution stage of a pipeline processing mechanism, the return address from the subroutine is pushed to the PC stack, and the pre-branch processing is performed to the address popped from the PC stack in decoding the subroutine return instruction in an instruction decoding stage.

Abstract: A data processor performs various types of EIT (exception, interrupt, trap) processing in connection with the execution of the preceding and following instructions in parallel. In one embodiment, an exception is detected resulting from processing the previous instruction in the pair being executed in parallel before completion of instruction processing where the exception requires re-execution. When the exception is detected a control means prevents the execution means from executing both preceding and following instructions. An additional feature is a control unit that controls when an interrupt is accepted during parallel execution. In another embodiment, a first decoder outputs suppressing information when the preceding instruction is a predetermined instruction having a possibility of causing a trap. A validity judgment circuit prevents the second decoded result from being issued when suppressing information is generated.

Abstract: A data processor comprises an instruction decoding unit having two decoders decoding respective instructions of an instruction group consisting of a plurality of instructions including a first instruction and a second instruction succeeding the first instruction, and a judging unit judging whether or not a combination of the first instruction and the second instruction can be executed in parallel and a bus for transferring two data in parallel between an operand access unit and an integer operation unit. The data processor uses a superscalar technique. Two instructions having an operand interference can be executed in parallel at high speed and two instructions accessing a memory can be executed in parallel without considerable hardware.

Abstract: A a data processing system capable of returning correctly from an exceptional processing by the same processing as that in the case of executing instructions one by one without particular control even if an exception occurs in the midway of the instruction processing, and capable of selecting a mode for executing instructions one by one in debugging or a test, so that a plurality of instructions are executed in parallel with simple control.

Abstract: A data processor in accordance with the present invention makes it possible to perform pre-branch processing with respect to a return address in the initial stage of pipeline processing also on a subroutine return instruction, and therefore by providing a stack memory (PC stack) dedicated to a program counter (PC) for storing only return addresses of the subroutine return instruction, in executing a subroutine call instruction in an execution stage of a pipeline processing mechanism, the return address from the subroutine is pushed to the PC stack, and the pre-branch processing is performed to the address popped from the PC stack in decoding the subroutine return instruction in an instruction decoding stage.

Abstract: A control unit (112) makes different judgments on the end address, depending on whether 1-word access or 2-word access, based on a post-update signal (507) and a 2-word access signal (508) which are internally generated and a coincidence signal (511) on the high-order 14 bits and another coincidence signal (512) on the bit 14 which are outputted from a comparator (158), and outputs a judgment result to a selector (155) as a selection signal (510). The selector (155) selects one of an output from an ALU (153) and an output from a latch (159) (the MOD.sub.-- S register 156) based on the selection signal (510). Having this structure, a data processor which enables access with modulo addressing in two different data-units can be provided.

Abstract: A second decoder (114) of an instruction decode unit (119) decodes an operation code for a multiply-add operation, and a second operation unit (117) receives two data stored in a register file (115) to perform the multiply-add operation. In parallel with the operations of the second decoder (114) and the second operation unit (117), a first decoder (113) of the instruction decode unit (119) decodes an operation code for 2 data load, and an operand access unit (104) causes two data (e.g., n bits each) stored in an internal data memory (105) to be transferred in parallel in the form of combined 2n-bit data to a first operation unit (116). Then, two predetermined registers of the register file (115) store the respective n-bit data from the first operation unit (116).