JPS6218935B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an external register writing method that allows data to be written into a part of an external register with a simple operation.

In general, general-purpose registers, floating point registers, etc. that are provided in local storage are called internal registers, and registers that are not provided in memory and whose bits directly control the hardware are called external registers. . One example of an external register is a program status word register. Rewriting the system mask of the program status word register is done frequently. A set system mask instruction is an instruction for rewriting the system mask. In conventional microprogram controlled computers, only one external address was given to the program status word register. The system mask of the program status word register is rewritten as follows. That is, the entire contents of the program state word register are read to another register, only the system mask is rewritten, and the program state word with the rewritten system mask is written to the original program state word register. Since the system mask indicates whether or not writing from a channel can be accepted, the system mask is frequently rewritten as described above. Therefore, the conventional method, which requires a considerable amount of time to rewrite the system mask, has the disadvantage that the efficiency of the processing device is reduced.

The present invention eliminates the above-mentioned drawbacks, and provides for a microprogram-controlled computer.
It is an object of the present invention to provide an external register writing method that allows partial writing of an external register with a simple operation. Therefore, in a microprogram-controlled processing device, the external register writing method of the present invention updates only a part of one external register by updating an external register corresponding to only one part and the entire external register. It is characterized in that an external address is set and data can be written to a part of the external register in one operation by a write command specifying an external address corresponding to only one part. be. Hereinafter, the present invention will be explained with reference to the drawings.

FIG. 1 is a diagram for explaining the assignment of external addresses to external registers, and FIG. 2 is a block diagram of one embodiment of the present invention. In the figure, 1 is a program status word register, 2-1 to 2-4 are byte unit registers that make up the program status word register, 3 and 4 are AND circuits, 5 is an OR circuit, and 6 is a bus. .

As shown in FIG. 1, the entire program status word register is assigned an external address EXT10, and the system mask of the program status word register is assigned an external address EXT11.

In FIG. 2, a clock is input to one input of the AND circuit 3 and one input of the AND circuit 4. The other input of the AND circuit 3 is connected to the decoder of the control storage data register. The other input of the AND circuit 4 is also connected to the decoder of the control storage data register.
The output of OR circuit 5 is connected to the clock terminal of register 2-1, and the output of AND circuit 3 is connected to the clock terminal of register 2-1.
-2, 2-3, and 2-4 clock terminals. Each byte signal line of path 6 is connected to a corresponding register 2-1, 2-2, 2-3, 2-4.

When a microinstruction indicating that data should be written from the control memory to the external address EXT10 is read to the control memory data, a signal of "1" is output on the signal line EXTW10, and this causes the AND circuit 3
outputs "1". When AND circuit 3 outputs "1", not only is data set in registers 2-2, 2-3, and 2-4, but also OR circuit 5 outputs "1", so register 2-1 is set. The data is also set. External address from control memory
When a microinstruction specifying that data is to be written to EXT11 is read into the control storage data register, a "1" signal is output on signal line EXTW11. This "1" signal opens the AND circuit 4, applies the clock CLK to the register 2-1, and sets data in the register 2-1. At this time, other registers 2-2, 2-3, 2
No data is written to -4. Register 2-1
corresponds to the system mask, so
The system mask can be rewritten in one operation.

As is clear from the above description, according to the present invention, an instruction to partially rewrite an external register can be executed at high speed.

[Brief explanation of the drawing]

FIG. 1 is a diagram for explaining the assignment of external addresses to external registers, and FIG. 2 is a block diagram of one embodiment of the present invention. 1...Program status word register, 2-1 to 2-4...Byte unit registers forming the program status word register, 3 and 4...AND circuit, 5...OR circuit, 6...bus.

Claims (1)

[Claims] 1 In a microprogram-controlled processing device, in order to update only a part of one external register, set an external address that corresponds to only the above part and an external address that corresponds to the entire external register, and update only a part of the above external register. An external register writing method characterized in that data can be written into a part of the external register in one operation by a write command specifying an external address to be written.