US 4,730,248 AGranted

Subroutine link control system and apparatus therefor in a data processing apparatus

AssigneeHitachi, Ltd.

InventorsHiroshi Watanabe, Takeshi Kato

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Abstract

A data processing apparatus having a subroutine processing function which saves and resumes the contents of general registers at the time of shifting into a subroutine or at the time of resume processing. Three layers of general registers are provided, each layer being comprised of a group of registers of a plurality of stages. The layers are connected in the form of a ring while coupling the corresponding registers of neighboring layers for each bit, so that the data can be batchwisely transferred in both directions. When shifted into a subroutine, the contents of a group of registers of the layer that had been used before the shifting are batchwisely transferred to a group of registers of a neighboring layers. The subroutine to which the operation is shifted uses the layer to which the data are transferred.

Claims8

Dependent claims

For operation of a data processing apparatus in the running of successive routines, including a plurality of general registers each for storing data necessary for operation of a routine, memory means for storing data received from said general registers, and means for transferring data from a general register to said memory means when the operation of the data processing apparatus is shifted from one routine into another routine and for retrieving from said memory means and restoring previously stored data to a general register when the one routine is resumed after execution of said other routine, a routine link control method comprising the steps of:

storing the data necessary to the operation of one routine in a first general register;
running said one routine on the basis of the data stored in said first general register;
copying the data in said first general register into a second general register when the operation of the data processing apparatus is shifted from said one routine to a second routine;
running said second routine on the basis of the data stored in said second general register;
copying the data in said second register into a third general register and storing the data from said first general register into said memory means when the operation of the data processing apparatus is shifted from said second routine to a third routine;
and
running said third routine on the basis of the data stored in said third general register.

4 more elements

Dependencies are inferred from the claim text.