JPH0760408B2 - Data processing device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data processing device that executes load / store instructions involving word crossing.

2. Description of the Related Art FIG. 4 is a block diagram of a conventional data processing apparatus, in which 1 is a data buffer for holding data, 7 is a data bus A for transferring data in the register file 1, and 8 is a register file 1. Data bus B for transferring the data within, 9 is a data bus Y for transferring the data, 10 is an external data bus for transferring the external data, 2 is input to data bus A7 and data bus 8, and the operation is performed. Data bus Y9
An arithmetic unit 3 for outputting the data on the data bus Y9, a store buffer 4 for receiving and holding the data on the data bus Y9, an output data aligner 4 for aligning the contents of the store buffer 3 and outputting the data to the external data bus 10, and 14 for the external data bus 10. Input data aligner for aligning data, 13 is an input data buffer for receiving and holding the output of the input data aligner 14, 12 is a selector for selecting the contents of the data bus Y9 and the input data buffer 13, 11 is a register file 1 and an arithmetic unit 2 And an execution control device that controls the selector 12, 15 is a word cross detector that detects a word cross, and 16a is an external device that inputs the result of the word cross detector 15 and controls the input data buffer 13 and the input data aligner 14 at the time of a load instruction. Input control device, 16b inputs the result of word cross detector 15 and stores buffer at the time of store instruction An external output control device for controlling the output data aligner 4 and.

The operation of the conventional apparatus configured as described above will be described with reference to FIG. First, in the case of a word cross (address: n + 2, size: word) in the load instruction, the word cross detector 15 detects the word cross and notifies the external input control device 16a of the result. The external input controller 16a controls the input data aligner 14 based on the address and size information to align the first word (address n) and write it in the input data buffer 13. The external input control device 16a holds the word cross state as it is and controls the alignment of the second word (n + 4 address), and the aligned data is written in the input data buffer 13. After that, the contents of the input data buffer 13 are transferred internally through the selector 12 and the data is written in the register file 1.

Further, in the case of the word cross at the time of the store instruction, the word cross detector 15 detects the word cross and notifies the external output control device 16b of the result. The external output controller 16b is
Similar to the case of the word cross at the time of the load instruction, the state of the word cross is held until the processing of the second word is completed, and the contents of the store buffer 3 are aligned and the first word and the second word are stored as external data. Output to the bus.

Therefore, if a word cross occurs, the execution controller
External input control device 16a, external output control device 16 independent of 11
Since b holds the word-cross state and processes data, it becomes difficult to control the load / store instruction execution accompanied by the word cross, and the consistency with the execution control device 11 also becomes a problem. Also, the testability of the external input / output device (3, 4, 13, 14) will be reduced.

As described above, in the above configuration, when a word cross occurs, the external input control device and the external output control device must hold the word cross state and process the data. However, there is a problem that it becomes difficult to control the load / store instruction at the time of execution, and the testability deteriorates.

In view of the above point, the present invention has an object to provide a data processing device that can more easily execute a load / store instruction when a word cross occurs.

Means for Solving the Problems The present invention relates to a register file for storing data, an arithmetic unit for arithmetically operating input data from the register file, a store buffer for holding a result obtained by the arithmetic unit, and the store buffer. Output data aligner that aligns the contents of the above and sends the data to the outside, a byte selector that selects the data from the outside and the operation result of the arithmetic unit in byte units and sends the data to the register file, and detects the word cross A word cross detector, a load controller connected to the word cross detector for controlling the register file, the arithmetic unit, and the byte selector when executing a load instruction and a normal load instruction involving word cross, It is connected to the word cross detector and store instruction with word cross and And a store control device that controls the store file, the arithmetic unit, the output data aligner, and the store buffer when executing a normal store instruction.

According to the present invention, with the above-described configuration, the load control device and the store control device manage the word cross state and control the entire data path unit, so that the load / load accompanying the word cross
Store instructions can be easily executed.

Embodiment FIG. 1 is a block diagram of a data processing device in an embodiment of the present invention. In FIG. 1, 1 is a register file for holding data, 7 is a data bus A for transferring data in the register file 1, 8 is a data bus B for transferring data in the register file 1, and 9 is data. Data buses Y and 10 are external data buses for transferring external data,
2 inputs the data bus A7 and the data bus B8 to perform calculation,
An arithmetic circuit for outputting the result to the data bus Y9, 3 is a store buffer for receiving and holding the data of the data bus Y9, 4
Is an output data aligner that aligns the contents of the store buffer 3 and outputs the data to the external data bus 10, and 5 has the function of aligning the data of the external data bus 10, and the aligned data and the data bus Y9 are in byte units. Byte selector for selecting and sending data to register file 1, 15 for word cross detector for detecting word cross, 6a for inputting result of word cross detector 15 and register file 1 and arithmetic unit 2 and byte selector for load instruction 5 is a load controller for controlling 5, 6b is a store controller for inputting the result of the word cross detector 15 and controlling the register file 1, arithmetic unit 2, store buffer 3 and output data aligner 4 at the time of a store instruction, 17 is a byte selector 5 is a flag generation device that generates a flag from the output of FIG.

The operation of the present embodiment configured as described above will be described below with reference to FIG.

First, the word cross in the load instruction (address: n +
(2, size: word), the word cross detector 15 detects a word cross and notifies the load controller 6a of the result. The load controller 6a controls the byte selector 5 based on the address and data size information to align the first word (nth address) and write it in TR (temporary register in register file). Then the second word (n
In the processing of +4 address), while the data of the external data bus 10 is aligned, the contents of TR are read from the register file 1 and passed through the arithmetic unit 2 to be output to the data bus Y9. The generated data is written in the register file 1. The flag required at this time is generated by the flag generation device 17.

Further, in the case of a word cross at the time of a store instruction, the word cross detector 15 detects the word cross and notifies the store control device 6b of the result. The store controller 6b reads the output data from the register file 1, passes through the arithmetic unit 2 and stores it in the store buffer 3. Next, the contents of the store buffer 3 are aligned and the first word and the second word are output to the external data bus.

As described above, according to the present embodiment, the configuration of the external data input device is simple (no input data buffer is required) due to the configuration in which the load control device 6a controls the data path unit (1, 2, 5) at the time of the load instruction. ), The critical path can be reduced. Also, at the time of a store instruction, the store control device 6b
Is configured to control the data path unit (1,2,3,4), so that the load control device 6a or the store control device 6b operates as the data path unit (1,2,3,4,5) when executing the load / store instruction. Since the state is always managed, the testability is also improved.

FIG. 3 is a block diagram of the control device of the data processing device showing the second embodiment of the present invention. In FIG. 3, reference numeral 60 is a microcommand generating device, and 61 is a microcommand decoding device.

The operation of the present embodiment configured as described above will be described below.

The microcommand generated by the microcommand generation device 60 is decoded by the microcommand decoding device 61, and the result is sent to the load control device 6a or the store control device 6b and the data path unit (1,2,3,4,5). Generate a control signal for. Micro-commands for executing load / store instructions especially involving word-cross will be described below.

For example, the following four commands are required as microcommands for executing the load / store instruction accompanied by word cross. Each operation corresponds to that described in FIG.

1) Load execution 1st word processing: LDWC1 2) Load execution 2nd word processing: LDWC2 3) Store execution 1st word processing: STWC1 4) Store execution 2nd word processing: STWC2 Therefore, the word cross at the time of load instruction execution LD in case
WC1 and LDWC2 may be executed, and STWC1 and STWC2 may be executed in the case of word cross at the time of executing the store instruction. Therefore, the bus retry operation by the load / store instruction can be easily executed only by generating the micro command. Further, the above-mentioned four operations (LDWC1, LDWC2, STWC1, STWC2) can be independently tested by the micro command, so that the testability is high.

As described above, according to the present embodiment, all the data path units including the external input / output unit are controlled by the micro command, so that all the processing related to the load / store instruction can be easily executed by the micro command. The testability of the department is further improved.

As described above, according to the present invention, the configuration of the external data input unit is simple due to the configuration in which the load control device controls all the processing at the time of the load instruction and the store control device controls all the processing at the time of the store instruction. Hardware can be reduced) and the critical path can be reduced. In addition, when controlling with microcommands, all the processing related to load / store instructions including word cross can be easily executed with microcommands, so tests can be easily executed by simply executing microcommands. , Its testability is also high, and its practical effect is great.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of an embodiment of the present invention, FIG. 2 is an explanatory diagram of a load instruction word cross operation of FIG. 1, and FIG. 3 is a configuration of a control device of another embodiment of the present invention. FIG. 4 is a configuration diagram showing a conventional configuration, and FIG. 5 is an explanatory diagram of a load instruction word cross operation of FIG. 1 ... Register file, 2 ... Arithmetic unit, 3 ... Store buffer, 4 ... Output data aligner, 5 ... Byte selector, 6a ... Load controller, 6b ... Store controller, 7 ... Data bus A, 8 ... Data bus B, 9 ...
Data bus Y, 10 ... External data bus, 11 ... Execution control device, 12 ... Selector, 13 ... Input data buffer, 14
...... Input data aligner, 15 …… Word cross detector,
16a ... External input control device, 16b ... External output control device,
60: Micro command generator, 61: Micro command decoder.

Claims (2)

[Claims] 1. A register file for storing data, an arithmetic unit for arithmetically operating input data from the register file, a store buffer for holding a result obtained by the arithmetic unit, and contents of the store buffer for alignment. Output data aligner for transmitting data to the outside, a byte selector for selecting the data from the outside and the operation result of the arithmetic unit in byte units and transmitting the data to the register file, and a word cross detector for detecting a word cross A load controller connected to the word cross detector for controlling the register file, the arithmetic unit, and the byte selector when executing a load instruction accompanied by a word cross and a normal load instruction; and the word cross detector. Connected store instruction with word cross and normal store instruction are executed. A data processing device and a store controller for controlling the store buffer the register file and the arithmetic unit and the output data aligner when. 2. The data processing device according to claim 1, wherein the load control device and the store control device are controlled by microcommands.