Preemptive multithreading computer system with clock activated interrupt

A method for operator-interactive preemptive concurrent multithreading execution of a plurality of instruction threads located within the same software program in a personal microcomputer system including a microprocessor having an interrupt input and clock driven means for periodically activating said interrupt input at brief predetermined intervals, said method comprising

• interrupting the execution of an executing instruction thread and preemptively taking control of the microprocessor away from said executing instruction thread in response to each said activation of said interrupt input,
• passing control of the microprocessor to another of said threads of said software program for execution of said another thread,
• thereafter returning control of the microprocessor to said interrupted thread to enable the latter to resume execution, at the point where said thread had been interrupted, until the next activation of said interrupt input by said clock driven means,
• actuating operator responsive means and thereby interactively controlling the execution of at least one of said program threads during the execution of said one thread,
• interactively displaying to an operator in real time the effects of said operator actuated control,
• whereby a thread of a program may execute interactively with the operator in the foreground while another thread of the same program executes in the background concurrently with the interactive execution of the foreground thread, and
• switching control of the microprocessor repeatedly back and forth between the foreground and background threads so rapidly that an interactive operator perceives the foreground and background threads to be executing simultaneously.

A method for preemptive multithreaded execution of a plurality of instruction threads located within the same multithreaded software program in a general-purpose computer system including a central processor having an interrupt operation and a clock timer for periodically activating said interrupt operation at brief predetermined time-sliced intervals, said method comprising

• interrupting the execution of an executing thread and taking therefrom control of the central processor upon each said activation of said interrupt operation,
• passing control of the central processor to another of said threads of said multithreaded software program for execution of said another thread,
• thereafter returning control of the central processor to said interrupted thread, and
• repeating the above-recited cycle of steps to switch control of the central processor from one thread to another thread and back again iteratively and rapidly so that the threads effectively execute simultaneously.

A multithreading software-programmable general-purpose computer system for concurrent processing of the same body of data code by at least two concurrently executing instruction threads constituting a single program, said computer system comprising:

• a central processing unit having an interrupt input,
• a memory,
• means for entry into said memory of a body of data code to be processed,
• means for operator selection and entry into said memory of a program comprising at least two concurrently executable instruction threads for processing said body of data code,
• means to cause the central processing unit to execute a first of said entered threads under control of said first thread to process the previously entered body of data code in accordance with a first mode of processing,
• clock means to repeatedly activate said interrupt input so as to interrupt execution of said first thread and preemptively switch control of the central processing unit to another of said entered threads for execution of said another thread so as to process the same previously entered body of data code in accordance with a second mode of processing, and
• means activated after each said interrupt input activation and its respective second mode of processing by said another thread to return control of the central processing unit to said first thread to enable said first thread to resume said first mode of processing said body of data code at the point in the code where the first thread had been interrupted.

A multithreading software-programmable general-purpose computer system for concurrently executing at least two instruction threads constituting a single program, said computer system comprising:

• a central processing unit having an interrupt input,
• a memory,
• means for operator selection and entry into said memory of a program comprising at least two concurrently executable instruction threads,
• means to cause the central processing unit to execute a first of said entered threads under control of said first thread, and
• clock means to repeatedly activate said interrupt input so as to interrupt execution of said first thread and preemptively switch control of the central processing unit to another of said entered threads for execution of said another thread.

A multithreading software-programmable general-purpose computer system for concurrent processing and modification of the same body of data code by at least two concurrently executing instruction threads constituting a single program, said computer system comprising:

• a central processing unit having an interrupt input,
• a memory,
• means for entry into said memory of a body of data code to be processed,
• means for operator selection and entry into said memory of a program comprising at least two concurrently executable instruction threads for processing said body of data code,
• a first of said threads including means for processing the previously entered body of data code, and a second of said threads including means for modifying the same previously entered body of data code,
• means to cause the central processing unit to execute said first thread to process said body of data code,
• means to repeatedly activate said interrupt input to interrupt the execution of said first thread and preemptively switch control of the central processing unit to said second thread for execution of the latter thread so as to modify said body of data code, and
• means activated after each said interrupt input activation and its respective modification of the body of data code by said second thread to return control of the central processing unit to said first thread to enable the latter to resume said processing of said body of data code at the point in the code where the first thread had been interrupted,
• said means to repeatedly activate said interrupt operation comprising clock timer means to periodically activate said interrupt operation at predetermined time intervals so that said threads obtain control of the central processing unit during alternate time slices of the running time of the latter.

A preemptive multithreading computer system for the concurrent execution of a plurality of instruction threads of the same program with each thread executing successive incremental portions of its task during successive timeslices of a respective series of spaced timeslices and with the timeslices of execution of each thread alternately interleaved with the timeslices of execution of at least one other thread, said system comprising

• a memory for storing a program comprising a plurality of sets of instructions with each set executable to provide a respective thread of execution and with each thread having a respective task to perform,
• central processing means having an interrupt operation,
• a clock for periodically actuating said interrupt operation at predetermined time intervals, and
• an interrupt service routine responsive to each said clock actuation of the interrupt operation to preempt an executing thread so as to terminate its timeslice of execution and take control of the central processing means away from said executing thread after the latter has executed only a portion of its task,
• said interrupt service routine passing said control of the central processing means to another thread thereby to invoke said another thread to perform the next successive portion of its task during the next successive timeslice of the respective series of timeslices of said another thread,
• whereby the above-recited cycle of clock actuated interrupt, thread preemption and thread invocation, is iterated repeatedly until the respective tasks are completed, and
• whereby a multithreading mode of operation is provided with said plurality of threads executing concurrently during their respective spaced interleaved timeslices with the successive executed task portions of each thread interleaved with the successive executed task portions of at least one other thread.

An operator-interactive preemptive multithreading software-programmable general-purpose personal microcomputer system for concurrent execution of a plurality of instruction threads located within the same software program and comprising

• a microprocessor having an interrupt input,
• means to cause the microprocessor to execute one of said threads under control of said one thread,
• clock driven means for periodically activating said interrupt input at brief predetermined time intervals so as to interrupt the execution of an executing thread upon each activation of said interrupt input,
• an interrupt service routine for preemptively taking control of the microprocessor in response to each said activation of said interrupt input and including means for passing control of the microprocessor to another of said threads of said software program for execution of said another thread,
• operator actuated means for interactively controlling the execution of at least one of said program threads during the execution of said one thread, and
• display means for interactively showing to the operator the effects of said operator actuated control,
• whereby a thread of a program may execute interactively with the operator in the foreground while another thread of the same program executes in the background concurrently with the interactive execution of the foreground thread, and
• said clock driven means and interrupt service routine coacting to switch control of the microprocessor repeatedly between the foreground and background threads so rapidly that an interactive operator perceives the foreground and background threads to be executing simultaneously.

A preemptive multithreading software-programmable general-purpose computer system for concurrent execution of a multithreaded software program having a plurality of concurrently executable instruction threads, said computer system comprising

• a central processor having an interrupt operation and means for executing a thread under control of the latter,
• a memory,
• a clock timer for periodically activating said interrupt operation at brief predetermined time-sliced intervals so as to interrupt the execution of an executing thread and to take therefrom control of the central processor upon each said activation of said interrupt operation, and
• an interrupt service routine responsive to each said clock timer activation of said interrupt operation for passing control of the central processor to another of said threads of said multithreaded software program for execution of said another thread,
• said clock timer, interrupt operation and interrupt service routine coacting to switch control of the central processor from one thread to another thread repeatedly and rapidly so that the threads effectively execute simultaneously.