JPS6380324A - Microcomputer circuit - Google Patents

Abstract

PURPOSE:To attain the block retrieval of data other than specific data by applying control or other processing to a block data 2-way buffer from a memory and to a unidirectional buffer in response to the result of comparison between the said block data and the specific data. CONSTITUTION:When a value other than a specific data is set to an accumulator of a microcomputer 1, an output of an operation mode selecting circuit 6 is inverted to an L level, the block data 2-way buffer 8 is closed by a buffer switch circuit 5 and a unidirectional buffer 7 is opened. Then a comparison output L from a comparator circuit 3 due to the noncoincidence between the specific data block of a latch circuit 4 and a data block from the memory 2 is fed to the computer 1 via the buffer 7 and the computer 1 inverts the output of the circuit 6 to H depending on the coincidence with the set value of the accumulator. Thus, the buffers 7, 8 are closed/opened respectively, the block data from the memory 2 is transferred to the computer 1, the block other than the specific data is retrieved to improve the data retrieval speed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a microcomputer circuit constructed using a microcomputer having a block search instruction.

[Conventional technology]

In a microcomputer circuit using a microcomputer, processing may be performed to search for specific data or data other than specific data stored in a memory. A common method of data retrieval is
Create a program that sequentially reads data from the start address of the memory to be searched to the search end address and compares it with specific data by combining memory read instructions, comparison instructions, etc. provided in the microcomputer. However, with such a method, creating a program is troublesome and the processing time is also long.

Therefore, in microcomputers, for example, Z-
80 (microcomputer manufactured by Zilog), there are known ones that have a block search instruction that allows searching for specific data in a certain range of memory areas (defeat detection) with one instruction. This has made searching for specific data easier and faster.

[Problem that the invention seeks to solve]

However, the Z-80 described above does not have an instruction to search a block of data other than specific data with one instruction, so when searching for data other than specific data in memory (for example, when searching for data other than O) In other words, when detecting discrepancies, it is necessary to perform a search using the general method described above, and the instructions to the microcomputer are troublesome, and the processing time is particularly high when the amount of data is large. The problem was enormous.

The present invention solves the above-mentioned problems, and its purpose is to enable searching for data other than specific data using a block search command for searching for specific data.

[Means for solving problems]

In order to solve the above-mentioned problems, the present invention provides a microcomputer circuit using a microcomputer having a block search instruction, including: a first data bus connected to the microcomputer; a second data bus connected to the second data bus via a bidirectional buffer; a latch circuit for latching specific data; and comparing the specific data latched by the latch circuit with the data on the second data bus. a comparison circuit; provided between the comparison circuit and the first data bus;
a unidirectional buffer that outputs data according to a comparison result of the comparison circuit to the first data bus; and an operation that selects a mode for determining whether or not the block search command is used to search for data other than the specific data. A mode selection circuit and a buffer opening/closing circuit for controlling opening/closing of the unidirectional buffer and bidirectional buffer according to the mode selected by the operation mode selection circuit are provided.

[For production]

When searching for data other than the specific data latched in the latch circuit by a block search command, the buffer opening/closing circuit opens the unidirectional buffer and closes the bidirectional buffer. Therefore, in this case, data corresponding to the comparison result of the comparison circuit is applied to the microcomputer via the unidirectional buffer and the first data bus. Therefore, the microcomputer can search for data other than specific data by executing a block search instruction to search for data output from the unidirectional buffer when the comparison result by the comparison circuit is inconsistent.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

In Figure 1, 1 is a microcomputer such as Z-80, 2 is a memory, 3 is a comparison circuit consisting of a magnitude comparator, etc., and 4 is a latch circuit that latches specific data when searching for data other than specific data. , 5 is a buffer opening/closing circuit, 6 is an operation mode selection circuit, 7 is a unidirectional buffer, 8 is a bidirectional buffer, 9 is an M1 signal Ml, 1
0 request signal 10RQ, memory request signal M
REQ.

A control signal bus through which read signals RD, write signals WR, etc. are transmitted, 10 is an address bus, 11° 11°
is a data bus, and 12 is an inverter.

The latch circuit 4 includes I10, which is made up of the microcomputer 1.
address is assigned and the microcomputer 1
Any 8-bit data can be written using an OUT instruction. Comparison circuit 3
compares the specific data latched in the latch circuit 4 with the data successively output from the memory 2, and sets the output signal to a predetermined one of high level and low level when the comparison does not match. Hereinafter, in this embodiment, if the comparison does not match, the comparator circuit 3 will set its output signal to a low level.

The operation mode selection circuit 6 sets its output signal to high level or low level under the control of the microcomputer 1. When the output signal of the operation mode selection circuit 6 is high level, specific data is selected by a block search command. A search is performed, and when the level is low, a block search command is used to search for data other than specific data. The buffer opening/closing circuit 5 controls opening/closing of the unidirectional buffer 7 and the bidirectional buffer 8.
When the output signal of the operation mode selection circuit 6 is at a low level and the microcomputer 1 outputs the address assigned to the memory 2 to the address bus 10 in order to read data stored in the memory 2, the control signal bus 9 Only when the above read signal RD is activated, the unidirectional buffer 7 is opened and the bidirectional buffer 8 is closed; otherwise, the unidirectional buffer 7 is closed and the bidirectional buffer 8 is opened. be. When the unidirectional buffer 7 is opened, it outputs the output signal of the comparator circuit 3 to the least significant bit and sets the other 7 bits to low level. Therefore, the data read from the memory 2 and the latch are output. If there is a mismatch with the specific data latched in the circuit 4, the unidirectional buffer 7 outputs 08 (all 8 bits are low level), and in other cases, 08 (all 8 bits are low level) is output. All 7 pinpoints will be output at low level).

Next, the operation when searching for data other than specific data using a block search command will be described. Note that in this case, the specific data is "n".

Before the microcomputer 1 executes the block search command, initial settings shown in (1) to (4) below are performed.

■ Turn on the Akiemulator in the microcomputer
Set.

■ Input specific data “n” to the latch circuit 4 using an out command.
”.

(2) Set the output signal of the operation mode selection circuit 6 to low level using the OUT command.

■ To the register bear H in the microcomputer 1,
Set the address of memory 2 to start the search.

(2) Enter the number of bytes in the byte counter BC in the microcomputer 1, indicating how many bytes to search for data starting from the address set in (2).

After the initial settings shown in ■ to ■ above are performed, the microcomputer l executes a block search instruction, and first, it searches the data stored at the address specified by the contents of the register pair HL in the memory 2. Then, the data on the data bus 11 is read. At this time, the output signal of the operation mode selection circuit 6 is set to a low level in the above-mentioned (2), and the microcomputer 1 reads the read signal on the control signal bus 9. Since RD is activated, the buffer opening/closing circuit 5 opens the unidirectional buffer 7 and closes the bidirectional buffer 8. Therefore, in this case, the microcomputer 1 reads data corresponding to the comparison result of the comparison circuit 3 applied via the unidirectional buffer 7 and the data bus 11.

Next, the microcomputer 1 compares the read data with the contents of the accumulator, and if the comparison fails, it sets a flag F as data other than the specific data "n" has been retrieved, and then changes the operating mode by an OUT command. The output signal of the selection circuit 6 is returned to a high level, that is, the accumulator is set to 08 in the above-mentioned case, and the specific data "n" latched in the latch circuit 4 and read from the memo IJ 2 are set. If the data do not match, the output of the unidirectional buffer 7 will be output as described above. Therefore, if the read data matches the contents of the Achiemulator, the microcomputer 1 will output data other than the specific data. This flag is set to indicate that the search has been performed.

If the comparison does not match, the microcomputer 1 increments the content of the register bear HL by +1 or -1, then -1 the content of the byte counter BC, and then sets the content of the byte counter BC to "0". Determine whether or not. If it is determined that the content of the byte counter BC has become rOJ, the execution of the block search instruction is finished, and then the output signal of the operation mode selection circuit 6 is returned to high level by the OUT instruction, and also set to "0". If it is determined that this is not the case, the same processing as described above is repeated until the contents of the accumulator match the read data or the contents of the byte counter BC become "0".

Although not explained in the above embodiment, when the output signal of the operation mode selection circuit 6 is set to high level to execute a block search command, the unidirectional buffer 7 is closed and the bidirectional buffer 8 is closed. is opened, and the data read from the memory 2 is applied to the microcomputer 1 via the data bus 11°, the bidirectional buffer 8, and the data bus 11. The same data as the data set in the accumulator will be retrieved.

〔Effect of the invention〕

As explained above, the present invention is capable of searching for data other than specific data by using a block search instruction for specific data searches that the microcomputer has. This has the advantage that data other than specific data can be searched more quickly than in the conventional example, in which data had to be compared.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an embodiment of the invention. In the figure, 1... microcomputer, 2...
Memory, 3... Comparison circuit, 4... Latch circuit, 5.
...buffer opening/closing circuit, 6...operation mode selection circuit,
7... Unidirectional buffer, 8... Bidirectional buffer, 9
...Control signal bus, 10...Address bus, 11.11'...Data bus, 12...Inverter.

Claims (1)

[Scope of Claim] In a microcomputer circuit using a microcomputer having a block search instruction, a first data bus connected to the microcomputer, and a connection between the first data bus and the bidirectional buffer. a second data bus connected; a latch circuit that latches specific data; a comparison circuit that compares the specific data latched by the latch circuit with data on the second data bus; and the comparison circuit. and the first data bus,
a unidirectional buffer that outputs data according to a comparison result of the comparison circuit to the first data bus; and an operation that selects a mode for determining whether or not the block search command is used to search for data other than the specific data. A microcomputer circuit comprising: a mode selection circuit; and a buffer opening/closing circuit that controls opening/closing of the unidirectional buffer and bidirectional buffer according to the mode selected by the operation mode selection circuit.