Task management apparatus

In a data processing system of the type in which each set of a plurality of sets of registers, one set being provided for each interrupt priority level in the system, interacts with a common main storage and common arithmetic and logic control circuits to execute respective tasks of a program, and in which a task dispatching program means operates in conjunction with priority/interrupt controls to dispatch tasks in a desired sequence to the sets of registers so that each set of registers, the arithmetic and logic unit and the main storage can process a respective task currently assigned to the latter set of registers when its priority is highest,

• in combination with said register sets, storage, control circuits, program means and priority/interrupt controls,
• apparatus, controlled in accordance with the execution of one machine level task instruction for assisting the dispatching of tasks, comprising
• a main storage area for holding a task address and status block (LSB) for each task for which execution is to be initiated or continued,
• means for fetching from main storage the LSB of a selected task and for storing the fetched LSB in the register set of a selected level,
• means for determining the in-process status of the selected task and the relative priority levels on which said one instruction of a current task is being executed and on which the selected task is intended for execution, and
• means responsive to said in-process status and said relative priority levels for enqueueing the selected task and continuing execution of the current task when the in-process status data is "on" and the priority level of the current task is higher than that of the selected task.

In a data processing system of the type in which each set of a plurality of sets of registers, one set being provided for each interrupt priority level in the system, interacts with a common main storage and common arithmetic and logic control circuits to execute respective tasks of a program, and in which a task dispatching program means operates in conjunction with priority/interrupt controls to dispatch tasks in a desired sequence to the sets of registers so that each set of registers, the arithmetic and logic unit and the main storage can process a respective task currently assigned to the latter set of registers when its priority is highest,

• in combination with said register sets, storage, control circuits, program means and priority/interrupt controls,
• apparatus, controlled in accordance with the execution of one machine level task instruction for assisting the dispatching of tasks, comprising
• a main storage area for holding a task address and status block (LSB) for each task for which execution is to be initiated or continued,
• means for fetching from main storage the LSB of a selected task and for storing the fetched LSB in the register set of a selected level,
• means for determining the in-process status of the selected task and the relative priority levels on which said one instruction of a current task is being executed and on which the selected task is intended for execution, and
• means responsive to said in-process status and said relative priority levels for changing from execution of the current task to execution of the selected task on the same priority level when the in-process states data is "on" and the selected and current priority levels are the same.

In a data processing system of the type in which each set of a plurality of sets of registers, one set being provided for each interrupt priority level in the system, interacts with a common main storage and common arithmetic and logic control circuits to execute respective tasks of a program, and in which a task dispatching program means operates in conjunction with priority/interrupt controls to dispatch tasks in a desired sequence to the sets of registers so that each set of registers, the arithmetic and logic unit and the main storage can process a respective task currently assigned to the latter set of registers when its priority is highest,

• in combination with said register sets, storage, control circuits, program means and priority/interrupt controls,
• apparatus, controlled in accordance with the execution of one machine level task instruction for assisting the dispatching of tasks, comprising
• a main storage area for holding a task address and status block (LSB) for each task for which execution is to be initiated or continued,
• means for fetching from main storage the LSB of a selected task and for storing the fetched LSB in the register set of a selected level,
• means for determining the in-process status of the selected task and the relative priority levels on which said one instruction of a current task is being executed and on which the selected task is intended for execution, and
• means responsive to said in-process status and said relative priority levels for continuing execution of the current task and maintaining the selected task suspended when the in-process status data is "off" and the priority level of the selected task is higher than that of the current task.

In a data processing system of the type in which each set of a plurality of sets of registers, one set being provided for each interrupt priority level in the system, interacts with a common main storage and common arithmetic and logic control circuits to execute respective tasks of a program, and in which a task dispatching program means operates in conjunction with priority/interrupt controls to dispatch tasks in a desired sequence to the sets of registers so that each set of registers, the arithmetic and logic unit and the main storage can process a respective task currently assigned to the latter set of registers when its priority is highest,

• in combination with said register sets, storage, control circuits, program means and priority/interrupt controls,
• apparatus, controlled in accordance with the execution of one machine level task instruction for assisting the dispatching of tasks, comprising
• a main storage area for holding a task address and status block (LSB) for each task for which execution is to be initiated or continued,
• means for fetching from main storage the LSB of a selected task and for storing the fetched LSB in the register set of a selected level,
• means for determining the in-process status of the selected task and the relative priority levels on which said one instruction of a current task is being executed and on which the selected task is intended for execution, and
• means responsive to said in-process status and said relative priority levels for continuing execution of the current task and suspending the selected task when the in-process status data is "off" and the priority level of the current task is higher than that of the selected task.

In a data processing system of the type in which each set of a plurality of sets of registers, one set being provided for each interrupt priority level in the system, interacts with a common main storage and common arithmetic and logic control circuits to execute respective tasks of a program, and in which a task dispatching program means operates in conjunction with priority/interrupt controls to dispatch tasks in a desired sequence to the sets of registers so that each set of registers, the arithmetic and logic unit and the main storage can process a respective task currently assigned to the latter set of registers when its priority is highest,

• in combination with said register sets, storage, control circuits, program means and priority/interrupt controls,
• apparatus, controlled in accordance with the execution of one machine level task instruction for assisting the dispatching of tasks, comprising
• a main storage area for holding a task address and status block (LSB) for each task for which execution is to be initiated or continued,
• means for fetching from main storage the LSB of a selected task and for storing the fetched LSB in the register set of a selected level,
• means for determining the in-process status of the selected task and the relative priority levels on which said one instruction of a current task is being executed and on which the selected task is intended for execution, and
• means responsive to said in-process status and said relative priority levels for suspending execution of the current task, examining the priority/interrupt controls for tasks pending on other levels and initiating execution of the highest priority pending task if one or more tasks are pending.

In a data processing system of the type in which each set of a plurality of sets of registers, one set being provided for each interrupt priority level in the system, interacts with a common main storage and common arithmetic and logic control circuits to execute respective tasks of a program, and in which a task dispatching program means operates in conjunction with priority/interrupt controls to dispatch tasks in a desired sequence to the sets of registers so that each set of registers, the arithmetic and logic unit and the main storage can process a respective task currently assigned to the latter set of registers when its priority is highest,

• in combination with said register sets, storage, control circuits, program means and priority/interrupt controls,
• a method of executing one machine level task instruction to assist the dispatching of tasks, comprising
• maintaining in main storage areas a task address and status block (LSB) for each task for which execution is to be initiated or continued,
• fetching from main storage the LSB of a selected task and storing the fetched LSB in the register set of a selected level,
• determining the in-process status of the selected task and the relative priority levels on which said one instruction of a current task is being executed and on which the selected task is intended for execution, and
• executing one of the following mutually exclusive steps in response to said in-process status and said relative priority levels:
• a. initiating the execution of the selected task when the in-process status is "on" and the priority level of the selected task is higher than that of the current task,
• b. enqueueing the selected task and continuing execution of the current task when the in-process status data is "on" and the priority level of the current task is higher than that of the selected task,
• c. changing from execution of the current task to execution of the selected task on the same priority level when the in-process states data is "on" and the selected and current priority levels are the same,
• d. continuing execution of the current task and maintaining the selected task suspended when the in-process status data is "off" and the priority level of the selected task is higher than that of the current task,
• e. continuing execution of the current task and suspending the selected task when the in-process status data is "off" and the priority level of the current task is higher than that of the selected task,
• f. suspending execution of the current task, examining the priority/interrupt controls for tasks pending on other levels and initiating execution of the highest priority pending task if one or more tasks are pending.