JPS5971548A - Microprogram controller - Google Patents

Abstract

PURPOSE:To decrease the capacitance of a storage section, by storing in advance a command code of a microprogram in a read only storage section and inputting directly the code to a register to decrease the command decoding time. CONSTITUTION:A microprogram corresponding to a command from a host device is stored in advance in a storage section C and the command code giving the microprogram is stored in advance in the read only storage section E. The 1st register B and the 2nd register D store respectively the access address to the storage sections C and E and the address is applied via lines 4 and 7. The command code of a command inputted from the host device to a control device A through a line 1 is inputted to the register D through a line 6. Further, a command code 8 read out from the storage section E is inputted directly to the register A through the circuit A and a line 3. Thus, a micro instruction 5 read out from the storage section C is inputted to the circuit A, where it is executed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Description of the technical field to which the invention pertains] The present invention relates to a microprogram control device that can be applied to an information processing device.

[Description of prior art]

Conventionally, this type of microprogram control device, for example, in a peripheral control device, processes a processing microprogram corresponding to a command received from a host device (central processing unit, channel, etc.) and the starting address of the processing microprogram. a memory that stores in advance a decoding microprogram for determining the decoding microprogram based on the command; and a memory that reads microinstructions for the decoding microprogram or the processing microprogram from the memory based on the command or the contents read from the memory. The device includes a register that receives an address for reading and holds the address, and control means that controls the memory and the register. In such a conventional configuration, when decoding all commands, the control means uses a decoding microprogram to decode all commands.
Since a method is adopted in which bit by bit is calculated and decoded or compared with constants in the microprogram, commands are The disadvantage is that the decoding time is long.

Recently, in order to improve the above-mentioned drawbacks, a method has been used in which all command codes are directly input to registers to reduce the command code time. However, in this method, the command code is used as an address to read the microinstructions of the decoding microprogram or the processing microprogram from memory, so the memory uses all the addresses that the command code can specify (
This has the disadvantage that microinstructions must be provided for commands (including illegal or unnecessary commands), which increases memory capacity.

DETAILED DESCRIPTION OF THE INVENTION An object of the present invention is to provide a microprogram control device that reduces command decoding time and reduces the number of firmware steps.

[Structure of the invention]

The device of the present invention includes: a first memory pre-stored with a microprogram corresponding to a command; a second memory pre-stored with a starting address of the microprogram; and a second memory IJ based on the command. 'The address for reading is input to the second
a register; a first register to which an address for reading microinstructions of the microprogram from the first memory is input based on contents read from the second memory or the first memory and holds an H address; 2 registers, the second memory, the first register, and the first memory are all provided with control means.

[Explanation of Rimoaki's embodiments]

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

The figure shows an embodiment of the present invention, which is a block diagram of a microprogram control device for a peripheral 1G control device, consisting of a section C, a second register D, and a read-only memory N<E.

The storage section C stores in advance a microprogram corresponding to a command from a host device (not shown), and the read-only storage section E stores the first number tlfi of this microprogram.
[This command code is stored in advance.]

The second register B and the second register D each have a storage section C.
and an access address for the read-only storage E, and supply them via lines 4 and 7, respectively.

The command code of the command input from the host device to the control device A through the line 1 is input to the second register D through the line 6, and the second register Bvc is a read-only memory.
The command code 8 read from AsE is input directly to the control circuit via line 3.

The microinstruction 5 read from the first memory C is input to the control circuit A and executed. That is,
If command code 8 is a command that is not defined in the peripheral control device, the corresponding status is reported to the higher-level device through line 1, and if it is a command that has not been defined, it is reported to the peripheral device ( (not shown).

[Detailed description of the invention]

In the present invention, by adopting the configuration described above, the contents of the first register become an address corresponding to the command code, and this is supplied to the storage unit storing the microinstructions, so that the command can be directly decoded. is now possible, reducing command decoding time,
In addition, since control can be performed using the converted command code, an invalid command code can be represented by one type of code, and the capacity of the storage unit can be reduced.

1←Eregistor, C...Storage section, D...Musister, E...Read-only storage section, 1.2, 3, 4, 6.7... Line, 5...
・Read out microinstruction, 8...
...Command code.

Claims (1)

[Scope of Claims] A first memory in which a microprogram corresponding to a command is stored in advance; a second memory in which a starting address of the microprogram is stored; a second register to which an address for reading is input and holds the address; and an address for reading the microinstructions of the microprogram from the first memory based on the contents read from the second memory or the first memory. 1. A microprogram control device comprising: a second register that receives an input address and holds the address; and a controller that controls the second register, the second memory, the second register, and the first memory.