JPS61157940A - Microprogram controller - Google Patents

Abstract

PURPOSE:To implement an indirect function control without making the word length of a micro instruction longer by providing a control circuit for action with the aid of the output of a decoder for decoding the micro instruction in order to control the indirect control. CONSTITUTION:The micro instruction for executing the indirect function is read out by a micro instruction register 3 and decoded by the decoder 4, and a control line 300 for the indirect function command is transmitted to the control circuit 9. In order to make the previously prepared contents of an indirect function register 5 into real control information instead of those of the register 3, the circuit 9 invalidates a current operation, and issues control lines 302 and 301 to a control memory address register 1 and the register 3, respectively, so as to suppress their updates, in order to expand a machine cycle. Moreover the circuit 9 issues a control line 303 to stop the executions of a general-purpose register 8 and an arithmetic device 7. The circuit 9 having received the control line 300 generates a control line 304, transmits it to a selector 6 and acts by giving the contents of the register 5 as control information to the general-purpose register 8 and the arithmetic device 7.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a control device for a processing device, and particularly to a microprogram control device when the control device is implemented using a microprogram control method.

Conventional technology A conventional microprogram control device is shown in FIG.

In FIG. 3, 1 is a control memory address register, 2 is a control memory, 3 is a microinstruction register, 4 is a decoder,
6 is an indirect function register for realizing an indirect function, 6 is a selector, 6 is an arithmetic unit, 7 is a general-purpose register, 100 is a control line directly assigned to the microinstruction register 3 to execute the indirect function, and 20o is a control line directly assigned to the microinstruction register 3. , the microinstruction register 3, the general-purpose register 8 that is subject to the logical operation of the microinstruction, and an internal bus that is a data transfer route for the arithmetic unit 7.

In the conventional microprogram control device configured as described above, a specific field of a microinstruction is converted into an indirect function command field in order to perform indirect function control in order to achieve flexibility of the microprogram and common use of microroutines. By allocating it as
Instead of the control status information in the microinstruction field, the selector 6 operates to read the control status information stored in the indirect function register 6 in advance into the microinstruction register 3 for the general-purpose register 8 and the arithmetic unit 7 that are the targets of the microoperation. An operation whose processing content is different from that of the issued microinstruction is realized.

FIG. 4 is a timing chart explaining the above operation. The control memory 2 is accessed from the content n of the control memory address register (CMAR) 1, and the microinstruction in is stored in the microinstruction register 3 after a predetermined time. Immediately, a control signal 160 for an indirect function command is issued from the microinstruction register 3, and the general-purpose register (GR) s and the arithmetic unit (ALU) 7 transfer data via the internal bus 200 in accordance with the command from the indirect function register 6. .

(For example, Hiroshi Hagiwara's "Microprogramming".

(October 6, 1972), Sangyo Tosho, P43) Problems to be Solved by the Invention However, in the above configuration, it is necessary to prepare specific fields of microinstructions to realize indirect functions. , the word length of the micro-instruction becomes long and the capacity of the control memory increases.

In view of this, an object of the present invention is to provide a microprogram control device that can perform indirect function control without increasing the word length of microinstructions.

Means for Solving the Problems The present invention provides a control memory address register, a control memory for storing a microprogram accessed by the contents of the control memory address register, and a microinstruction read from the control memory. A microinstruction register to store a microinstruction, a decoder to decode the microinstruction, an indirect function register provided for the purpose of indirect function control, the output of this register, a selector that receives the output of the microinstruction register as input, and a selector of this selector. A general-purpose register and arithmetic unit that operate using output as control information, a control line issued from the decoder when indirect function control is executed, a control circuit that uses this control line as input and issues a control signal for indirect function control, and Independent control lines sent from the control circuit to the control storage address register, the microinstruction register, the selector, and the general-purpose register and arithmetic unit, the microinstruction register 3, the indirect function register, and the This is a microprogram control device that includes a general-purpose register and at least one bus that connects the arithmetic unit and serves as a data transfer route.

According to the above-described configuration, the present invention provides a control circuit that operates for indirect function control based on the output of a decoder that decodes the microinstruction, without providing a field for indirect function control in a specific field of the microinstruction. In particular, indirect control functions can be realized.

Embodiment FIG. 1 shows a configuration diagram of a microprogram control device in an embodiment of the present invention.

In Figure 1, 1 is a control address register, 2 is a control memory that stores a microprogram, 3 is a microinstruction register that holds the output of control memory 2, 4 is a decoder that decodes the contents of microinstruction register 3, and S is an indirect 6 is an indirect function register for controlling functions; 6 is a selector that receives the outputs of indirect function register 5 and microinstruction register 3; 7 is a general-purpose register; and 8 is an arithmetic unit that receives the output of selector 6 as control information. do.

Reference numeral 9 denotes a control circuit that issues control signals for indirect function control. 300 is a control line sent from the decoder 4 to the control circuit 9 when indirect function control is executed; 30, 302, 303 .
304 is a control line that receives the control line 300 and is sent from the control circuit 9 to the microinstruction register 3, the control address register 1, the general-purpose register 7, the arithmetic unit 8, and the selector 6; 200, the microinstruction register 3; The operation of the microprogram control device of this embodiment, which is configured as 0 or more buses connecting the indirect function register 6, the general-purpose register 7, and the arithmetic unit 8 and serving as a means for transferring information, will be described below.

The processing process in which a read indirect function control microinstruction is executed will be described when the control storage address register stores an address of a control storage in which a microinstruction for executing an indirect function is stored.

The contents of the processing at this time are performed according to the timing chart shown in FIG. The ○ numbers in FIG. 2 correspond to the explanation numbers below.

(2) Control memory 2 at address N is accessed according to N stored in control memory address register (CMAR) 1, and microinstruction 1n is read out to microinstruction register 3 after a specified time.

■ The microinstruction in that executes the indirect function is decoded by the decoder 4 and sent to the control line 300 for the indirect function command.
is sent to the control circuit 9.

On the contrary, in order to make the contents of the indirect function register 6 prepared in advance the true control information, a control line is sent to the control memory address register 1 in order to invalidate the current operation and extend the machine cycle at the same time. 302 to suppress the update of the control memory address register (CMAR) 10, and control line 3 to the microinstruction register (MIR) a.
01 to suppress the update of the microinstruction register (MIR) 3, and also
A control line 303 is issued to LU)a to stop execution.

■ The control circuit 9, which receives the control signal SOO one machine cycle after the indirect function execution microinstruction in is stored in the microinstruction register (MIR) 3, generates the control line 304 and sends it to the selector 6 to execute the indirect function execution. The contents of the function register 6 are used as control information for the general-purpose register 7 and the arithmetic unit 8.

As described above, according to the present invention, flexible indirect function control can be performed in each operation of a microinstruction without providing a specific field of a microinstruction word for indirect function control. shows the case where the execution cycle is extended by one machine cycle, but when one machine cycle is composed of multiphase clocks,
It goes without saying that the clock of a specific phase may be extended.

As described in detail, according to the present invention, indirect function control can be performed without increasing the word length of microinstructions, and flexible functions can be realized with compact microinstructions. A microprogram control device can be constructed, and its practical effects are great.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram of a microprogram control device according to an embodiment of the present invention, FIG. 2 is a timing chart explaining the operation of the same embodiment, FIG. 3 is a configuration diagram of a conventional microprogram control device, and FIG. The figure is a timing chart explaining the operation of the conventional example. 1... Control address register, 2...
Control memory, 3... Microinstruction register, 4.
...Deduder, 6...Indirect function register, 6...Selector, 7...Arithmetic unit, 8
...General-purpose register, 9...Control circuit. Name of agent: Patent attorney Toshio Nakao, 1 person, 1 person, 3rd figure, $411

Claims (1)

[Claims] a control memory address register; a control memory that stores a microprogram accessed by the contents of the control address register; a microinstruction register that stores microinstructions read from the control memory; a decoder that decodes the microinstructions; An indirect function register provided for the purpose of function control, a selector that receives the output of this indirect function register and the output of the microinstruction register as input, and a general-purpose register and arithmetic unit that operate using the output of this selector as control information. , a control line issued from the decoder when executing indirect function control, a control circuit that takes this control line as input and issues a control signal line for indirect function control, and this control circuit sends the above microinstruction to the control storage address register. independent control lines sent to the register, the selector, and the general-purpose register and the arithmetic unit; the general-purpose register, the arithmetic unit;
A microprogram control device comprising at least one bus that connects the microinstruction register and the indirect function register and serves as a data transfer path.