JPS5935451B2 - General purpose register access method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an arithmetic circuit for an electronic computer and a communication control device.

General-purpose registers in electronic computers and communication control devices are a group of multiple registers that can be used in programs.
It is positioned as a local memory so that it does not occupy an area in the main memory.

Conventionally, general-purpose registers in this type of arithmetic device are IC
It consists of memory elements, and general-purpose registers are accessed by providing address data (a field indicating the interrupt program level and the general-purpose register number in the instruction register). Therefore, according to this method, the delay in the access time of the memory element affects the instruction execution time. In addition, when executing register-to-register type instructions, inputs cannot be prepared for the arithmetic circuit at the same time, so two inputs are required for the general-purpose register.
degree access is required. The block diagram in FIG. 1 and the time chart in FIG. 2 illustrate the above situation.

In Figure 1, 1 is a general-purpose register, 2 is an arithmetic circuit, and 3 is a general-purpose register.
is an arithmetic register. In the arithmetic circuit 2, when calculating the values of R1 and R2 in general-purpose register 1 and putting the calculation result into R1 in general-purpose register 1, first
1 is accessed and read out, it is placed in the arithmetic register 3, then R2 is accessed and read out, R1 and R2 in the arithmetic register 3 are operated on, and the operation result is placed in the R1 position of the general purpose register 1. That is, from the perspective of the arithmetic circuit, there is a drawback in that the general-purpose register can only be accessed using addresses on one side. SUMMARY OF THE INVENTION An object of the present invention is to provide a general-purpose register access method that eliminates the above-mentioned drawbacks and has the effect of allowing general-purpose registers to be accessed using two addresses. and an arithmetic circuit, in a general-purpose register access method for inputting data in two general-purpose registers among the plurality of general-purpose registers to the arithmetic circuit to perform an arithmetic operation, the method further comprises: a plurality of general-purpose register groups; A duplex switching circuit is provided between the general-purpose register group and the arithmetic circuit, and a register from the plurality of general-purpose register groups is selected using the interrupt program level as address information, and data is read from the selected register. The read data is selected by the switching circuit and inputted to the arithmetic circuit.

The present invention will be described below with reference to one embodiment thereof.

FIG. 3 is a block diagram showing one embodiment of the present invention. In the figure, 11 is a general-purpose register, 112 is a switching circuit, and 13 is an arithmetic circuit. As shown in FIG. 3, this device has five interrupt program levels, and several general-purpose registers are accessible for each level.

When interrupt program level 5 is given as address data to general-purpose register 11, the contents of the general-purpose register of the active interrupt program level are as follows.
It is arranged to remain in the same state as it was read. By the double switching circuit 12 placed before the arithmetic circuit 13,
Required data is selected from the contents of the general-purpose register 11 that has been read out and is simultaneously input to the arithmetic circuit 13. The selection control signal of the switching circuit 12 at this time is a field indicating the general-purpose register number in the instruction register. In the example shown in Figure 3, interrupt program level 4
This indicates that the general-purpose register 11 is interrupted and RO(!:Rn is simultaneously input to the arithmetic circuit 13. Therefore,
There is no need to be aware of delays in the access time of general-purpose registers as in the past, and data can be input to the arithmetic circuit simultaneously with a single access. In other words, it is possible to access a general-purpose register using addresses on two sides.
As explained above, the present invention uses the interrupt program level as an address, selects the read data of the general-purpose register that is always in the read state, and simultaneously inputs it to the arithmetic circuit. By letting
This has the effect of significantly shortening the instruction execution time.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing access to a conventional general-purpose register, FIG. 2 is a time chart thereof, and FIG. 3 is a block diagram of an embodiment of the present invention. The numbers in the figure indicate the following. 1... General-purpose register, 2... Arithmetic circuit, 3... Arithmetic register, 11... General-purpose register, 12...
...Switching circuit, 13... Arithmetic circuit.

Claims (1)

[Claims] 1. In a general-purpose register access method that has a plurality of general-purpose registers and an arithmetic circuit and inputs data in two general-purpose registers among the plurality of general-purpose registers to the arithmetic circuit to perform an operation, a general-purpose register group and a duplex switching circuit between the general-purpose register group and the arithmetic circuit, selects a register from the plurality of general-purpose register groups using the interrupt program level as address information, and selects a register from the selected register. A general-purpose register access method characterized in that data is kept in a read state, and the read data is selected by the switching circuit and inputted to the arithmetic circuit.