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).

Abstract: A data processor, comprising: an instruction fetch unit 111 which fetches instructions from a memory which stores instructions; an instruction decoding unit 112 which decodes the instructions fetched from the instruction fetch unit 111; an instruction execution unit which executes the instructions on the basis of the decoding result by the instruction decoding unit 112; a program counter (DPC) 29 which holds an address of the instruction being decoded in the instruction decoding unit 112; and a branch target address calculation unit 1 which is connected to the instruction fetch unit 111 and the program counter (DPC) 29, adds a value of a branch displacement field transferred from the instruction fetch unit 111 and the instruction address transferred from the program counter (DPC) 29, and transfers the addition result to the instruction fetch unit 111, so that jump instruction can be processed efficiently by pipeline processing.

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 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 data processor, comprising: an instruction fetch unit 111 which fetches instructions from a memory which stores instructions; an instruction decoding unit 112 which decodes the instructions fetched from the instruction fetch unit 111; an instruction execution unit which executes the instructions on the basis of the decoding result by the instruction decoding unit 112; a program counter (DPC) 29 which holds an address of the instruction being decoded in the instruction decoding unit 112; and a branch target address calculation unit 1 which is connected to the instruction fetch unit 111 and the program counter (DPC) 29, adds a value of a branch displacement field transferred from the instruction fetch unit 111 and the instruction address transferred from the program counter (DPC) 29, and transfers the addition result to the instruction fetch unit 111, so that jump instruction can be processed efficiently by pipeline processing.

Abstract: A data processor, comprising: an instruction fetch unit 111 which fetches instructions from a memory which stores instructions; an instruction decoding unit 112 which decodes the instructions fetched from the instruction fetch unit 111; an instruction execution unit which executes the instructions on the basis of the decoding result by the instruction decoding unit 112; a program counter (DPC) 29 which holds an address of the instruction being decoded in the instruction decoding unit 112; and a branch target address calculation unit 1 which is connected to the instruction fetch unit 111 and the program counter (DPC) 29, adds a value of a branch displacement field transferred from the instruction fetch unit 111 and the instruction address transferred from the program counter (DPC) 29, and transfers the addition result to the instruction fetch unit 111, so that jump instruction can be processed efficiently by pipeline processing.

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, comprising: an instruction fetch unit 111 which fetches instructions from a memory which stores instructions; an instruction decoding 112 which decodes the instructions fetched from the instruction fetch unit 111; an instruction execution unit which executes the instructions on the basis of the decoding result by the instruction decoding unit 112; a program counter (DPC) 29 which holds an address of the instruction being decoded in the instruction decoding unit 112; and a branch target address calculation unit 1 which is connected to the instruction fetch unit 111 and the program counter (DPC) 29, adds a value of a branch displacement field transferred from the instruction fetch unit 111 and the instruction address transferred from the program counter (DPC) 29, and transfers the addition result to the instruction fetch unit 111, so that jump instruction can be processed efficiently by pipeline processing.

Abstract: A data processor, comprising: an instruction fetch unit 111 which fetches instructions from a memory which stores instructions; an instruction decoding unit 112 which decodes the instructions fetched from the instruction fetch unit 111; an instruction execution unit which executes the instructions on the basis of the decoding result by the instruction decoding unit 112; a program counter (DPC) 29 which holds an address of the instruction being decoded in the instruction decoding unit 112; and a branch target address calculation unit 1 which is connected to the instruction fetch unit 111 and the program counter (DPC) 29, adds a value of a branch displacement field transferred from the instruction fetch unit 111 and the instruction address transferred from the program counter (DPC) 29, and transfers the addition result to the instruction fetch unit 111, so that jump instruction can be processed efficiently by pipeline processing.

Abstract: This invention relates to a data processor with pipelining system, which is provided with at least two stages each having working stackpointers, and so constructed that each stage can independently refer to the working stackpointer corresponding to each stage, and the renewal of each working stackpointer corresponding to each stage occurs synchronously with pipeline processing, so that when execution of a plural instructions including designation of operands under stack-push addressing mode and stack-pop addressing mode, result of address calculation executed at the address calculation stage is sequentially transferred to a corresponding working stackpointer in a next pipeline stage. This is synchronized with the transfer of instructions through the stages of pipeline, thereby being possible for the data processor to smoothly execute pipelining process.

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, comprising: an instruction fetch unit 111 which fetches instructions from a memory which stores instructions; an instruction decoding unit 112 which decodes the instructions fetched from the instruction fetch unit 111; an instruction execution unit which executes the instructions on the basis of the decoding result by the instruction decoding unit 112; a program counter (DPC) 29 which holds an address of the instruction being decoded in the instruction decoding unit 112; and a branch target address calculation unit 1 which is connected to the instruction fetch unit 111 and the program counter (DPC) 29, adds a value of a branch displacement field transferred from the instruction fetch unit 111 and the instruction address transferred from the program counter (DPC) 29, and transfers the addition result to the instruction fetch unit 111, so that jump instruction can be processed efficiently by pipeline processing.

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 capable of efficiently processing jump instructions including an instruction fetch unit for fetching instructions from a memory, an instruction decoding unit for decoding instructions fetched by the instruction fetch unit, an instruction executing unit for executing instructions according to the decoding result of the instructions, a PC calculation unit for holding a head address of an instruction being decoded at the instruction decoding unit, adders for selectively inputting respective values of branch displacement fields transferred from the instruction fetch unit responsive to a part of a value of an instruction code field transferred from the instruction fetch unit so as to add it to the head address of the instruction transferred from the PC calculation unit, and a JA bus for transferring the addition results to the instruction fetch unit.

Abstract: A data processor which comprises: an instruction decoding unit for decoding the instruction; an operand address calculating unit having an adder and an output latch holding the added result and calculating addresses of plural memory operands, in accordance with address calculation control code outputted from the instruction decoding unit; and an instruction executing unit for executing the instruction, in accordance with the operand address outputted from the operand address calculating unit and an operation control code outputted from the instruction decoding unit; and is capable of executing the plural data operating instruction for processing plural data at high efficiency, by performing address calculation of the plural operands by the operand address calculating unit before executing the instruction by the instruction executing unit.

Abstract: A pipelined data processor decomposes an instruction into a plurality of processing units (step codes), each corresponding to an operand of the instruction. In the register direct addressing mode, where the source operand of the instruction is an immediate value and the destination operand of the instruction is a register, the data processor combines the two step codes associated with the two operands into one. Thus, the number of cycles required for processing the instruction is reduced.

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 bit searching circuit includes an offset value designating circuit, a bit position detecting circuit, a count circuit, and a search-end detecting circuit. The offset value designating circuit outputs an offset value indicating a search-start position. The bit position detecting circuit searches for the first bit position which has a first binary value, in a search field between the bit position designated by the offset value and a last bit position in a bit string. The count circuit counts the number of bits in the search field having the first binary value. The search-end detecting circuit detects the end of search processing by subtracting the bit counts detected by the bit position detecting circuit from the count value counted by the count circuit until the result is zero. A data processor using such a bit searching circuit includes a control unit and an instruction execution unit.

Abstract: A device and method for generating execution controlling information (operation designating parameter) for an instruction execution means is provided. The device operates by selecting and composing a parameter (bit field) selected from among the bits of an instruction code and a parameter obtained as a result of decoding the instruction to be executed. The process makes it possible to reduce the size of a micro ROM by processing one instruction having various formats by the same micro-instruction.