JPS62232033A - Microprogram control device - Google Patents

Abstract

PURPOSE:To reduce the capacity of a storage device by making it possible to store microinstructions that control a controlled circuit that requires continual control in a storage unit that stores microinstructions that control a controlled circuit that requires control only in a specified step. CONSTITUTION:The arithmetic block 2 of an arithmetic circuit 1 is an arithmetic block that requires continual control, and the arithmetic block 3 does not require continual control but requires control only in a step designated specially. These arithmetic blocks 2 and 3 are controlled by microinstructions set to control registers 7 and 8 respectively. When a microinstruction held in the control register 7 is a microinstruction for branching and includes a branching address, a switching circuit 10 selects this branching address as a reading address 20, and in other cases, selects an address made by +1 to a reading address 1 step before as a reading address 20.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a microprogram control device, and particularly to an information processing device using a microprogram control method.

[Conventional technology]

Conventionally, this type of microprogram control device has adopted one of the following control methods when the number of microinstruction bits required for microcontrol differs in each step of microcontrol.

■ A method that adjusts the number of focuses per microinstruction to the step with the maximum number of bits required for microcontrol.

■ A method in which the number of bits per microinstruction is set as n (a positive integer), and all steps or the missing bits are controlled by hardware for microcontrol.

[Problem that the invention seeks to solve]

The above-mentioned conventional microprogram control device has the disadvantage that when adopting the control method (2), the capacity of the storage device in which microinstructions are stored becomes larger than necessary.

Furthermore, when using the control method (2), there is a drawback that the expandability and flexibility of the control method are reduced.

In view of the above points, an object of the present invention is to reduce the capacity of a storage device in which microinstructions are stored without relying on hardware control when the number of instructions required for microcontrol differs in each step of microcontrol. The purpose is to provide a microprogram control device that can

[Means for solving problems]

The microprogram control device of the present invention includes a first controlled circuit that needs to be controlled by micro instructions at all times, a second controlled circuit that needs to be controlled by micro instructions only in specific steps, and a second controlled circuit that stores micro instructions. first and second
In the step of controlling only the storage device and the first controlled circuit, the first controlled circuit is controlled by a microinstruction stored in the first or second storage device;
In the step that requires control of both the controlled circuit and the second controlled circuit, the first controlled circuit is controlled by a microinstruction stored in the first storage device, and the second controlled circuit is controlled by the microinstruction stored in the first storage device. and switching means for switching to control the second controlled circuit according to microinstructions stored in the second controlled circuit.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a block diagram showing one embodiment of the present invention. The microprogram control device of this embodiment includes an arithmetic circuit 1 consisting of two arithmetic blocks 2 and 3 that can be controlled independently, and a microinstruction block. Storage devices 4 and 5 are control memories to be stored, a switching circuit 6 selects microinstructions to be read from the storage devices 4 and 5, and storage device 4.
and control registers 7 and 8 that hold the microinstructions read from 5, an address register 9 that stores the read address 20 which is the lower bits excluding the most significant bit 21 of the address, and an address register 9 that stores the address used as the read address 20. It is comprised of a switching circuit 10 for selection and an adder 11 for incrementing the read address 20 by 1.

The calculation block 2 of the calculation circuit 1 is a calculation block that always requires control, and the calculation block 3 is a calculation block that does not always require control but only at specifically designated steps. These operation blocks 2 and 3 are controlled by microinstructions set in control registers 7 and 8, respectively.

In the step of controlling only the calculation block 2, the storage devices 4 and 5 store microinstructions for controlling the calculation block 2. In this case, the microinstruction has the control focus 22 at 0°. A switching circuit 6 selects which microinstruction stored in the storage device 4 or the storage device 5 is used to control the arithmetic block 2 in accordance with the most significant dot 21 of the address.

That is, the switching circuit 6 selects the most significant bit 21 of the address.
When is 0°, the microinstruction to be read from the storage device 4 is selected, and when it is “1”, the microinstruction to be read from the storage device 5 is selected.

In steps where it is necessary to control both arithmetic blocks 2 and 3, the storage devices 4 and 5 are provided with a microinstruction for controlling the arithmetic block 2 and a control bit 2 in the storage device 4.
A microinstruction in which 2 is 1 is stored, and a microinstruction for controlling the calculation block 3 is stored in the storage device 5. In this case, as illustrated in FIG. 2, the address of the microinstruction stored in the storage device 5 matches the address of the microinstruction of the corresponding step in the storage device 4. Therefore, even if the microinstruction is stored in the storage device 5, the most significant bit 21 of the address is not 'O' but '0'.

The switching circuit 6 selects the microinstruction from the storage device 4 when the most significant bit 21 of the address is 0°, and sets it to “1”.
A microinstruction from the storage device 5 is selected when .

The microinstructions set in the control register 7 include a microinstruction word that controls the calculation block 2, a control bit 22 that instructs the validity or invalidity of the microinstruction set in the control register 8, and a microinstruction word set in the control register 7. This includes the branch address when the microinstruction is a branch microinstruction.

The microinstruction set in the control register 8 includes a microinstruction word for controlling the calculation block 3.

In the address register 9, the next successive address (current successive address+1) 20 other than when branching is sequentially set.

If the micro-instruction held in the control register 7 is a branch micro-instruction and includes a branch address, the switching circuit 10 selects this branch address as the continuation address 20, and in other cases selects the branch address as the continuation address 20. The address added by 1 to the previous read address is selected as the subsequent address 20.

Next, the operation of the microprogram control device of this embodiment configured as described above will be explained.

In order to simplify the explanation, the address of the microinstruction is assumed to be 4 bits as shown in FIG. In the example shown in the figure, microinstructions C', E', and F' are microinstructions that control arithmetic block 3, and other microinstructions are microinstructions that control arithmetic block 2.

In the step of executing microinstruction A, the most significant bit 21 of the address is °0°, and the read address 20 is 000.
Therefore, the output of the switching circuit 6 becomes the microinstruction A, and the microinstruction A is stored in the control register 7. Therefore, the operation block 2 is controlled by this microinstruction A. On the other hand, control register 8
The microinstruction (2) read from the storage device 5 is stored in the microinstruction (2), but since the control bit 22 of the microinstruction (A) is 0', the operation block 3 is not controlled.

In the step of executing microinstructions c and c', the most significant bit 21 of the address is 0°, and the read address 2 is
Since 0 is 010', the output of the switching circuit 6 becomes the microinstruction C, and the microinstruction C is stored in the control register 7. Therefore, the microinstruction C controls the calculation block 2. On the other hand, the control register 8 stores the microinstruction C'' read out from the storage device 5, and since the control 2I bit 22 of the microinstruction C is 1°, the arithmetic block 3 is controlled by the microinstruction C°. Ru.

In the step of executing the microinstruction ■, the most significant bit 21 of the address is 1', and the read address 20 is 000.
°, the output of the switching circuit 6 is the microinstruction ■, and the control register 7 stores the microinstruction I. Therefore, the microinstruction I controls the calculation block 2. In addition, control register 8
The microinstruction I read from the storage device 5 is also stored in the microinstruction 5, but since the control bit 22 of the microinstruction I is '0°, the arithmetic block 3 is not controlled.

〔Effect of the invention〕

As explained above, the present invention enables a storage device that stores microinstructions to control a controlled circuit that needs to be controlled only in a specific step to also store microinstructions that control a controlled circuit that needs constant control. By doing so, it is possible to reduce the capacity of the storage device without using hardware control.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of a microprogram control device of the present invention, and FIG. 2 is a diagram showing an example of a storage state of microinstructions in the storage device shown in FIG. 1. In the figure, 1... Arithmetic circuit, 2.3... Arithmetic block (controlled circuit), 4.5...
・Storage device, 6.10...Switching circuit, 7.8...Control register, 9...Address register, 11...Adder, 20...Read address, 21 ...Address most significant bit, 22...
It is a control bit.

Claims (1)

[Scope of Claims] A first controlled circuit that needs to be controlled by micro-instructions at all times, a second controlled circuit that needs to be controlled by micro-instructions only in specific steps, and a first controlled circuit in which micro-instructions are stored. and a second storage device, and in the step of controlling only the first controlled circuit, the first
Alternatively, in the step in which the first controlled circuit is controlled by a microinstruction stored in a second storage device, and it is necessary to control both the first controlled circuit and the second controlled circuit, the first switching means for switching between controlling the first controlled circuit using micro instructions stored in the storage device and controlling the second controlled circuit using the micro instructions stored in the second storage device; A microprogram control device comprising: