Method of processing interrupts in a digital computer system

Claim 1

A method for operating a digital computer with an operating system program, said operating system program comprising a plurality of subroutines, said computer including memory, input-output devices, a system clock, initialization means to boot-up said computer, and a microprocessor, said microprocessor including a plurality of modes, a mode switch means capable of switching said microprocessor from a first mode to alternate modes but incapable of switching back to said first mode, and means for resetting said microprocessor, said resetting means causing said microprocessor to boot-up in said first mode, said method providing means for efficiently running on said computer applications programs adapted to said first mode concurrently with computer applications programs adapted to said alternate modes by switching between modes when necessary, said method comprising the steps of: (a) booting up said computer; (b) loading into said memory and said microprocessor operating system programs; (c) running a plurality of said applications programs on said microprocessor as required; (d) determining as each program is run whether a mode switch is required; (e) if a switch from said first mode to one of said alternate modes is required, activating said mode switch means; (f) if a switch from an alternate mode to said first mode is required, causing said microprocessor to reset by activating said resetting means by control means; (g) determining whether said resetting was triggered by said control means rather than by power-up, hardware faults, or a malfunction in the operation of the computer; and (h) if said resetting is determined to have been caused by said control means, causing said computer to bypass normal initialization routines during boot-up.

Claim 2

A method for operating a digital computer with an operating system program, said operating system program comprising a plurality of subroutines, said computer including memory, input-output devices, a system clock, initialization means to boot-up said computer, and a microprocessor, said microprocessor including a plurality of modes, a mode switch means capable of switching said microprocessor from a first mode to alternate modes but incapable of switching back to said first mode, and means for resetting said microprocessor, said resetting means causing said microprocessor to boot-up in said first mode, said method providing means for efficiently running on said computer applications programs adapted to said first mode concurrently with computer applications programs adapted to said alternate modes by switching between modes when necessary, said method comprising the steps of: (a) booting up said computer; (b) loading into said memory and said microprocessor operating system programs; (c) running a plurality of said applications programs on said microprocessor as required; (d) determining as each program is run whether a mode switch is required; (e) if a switch from said first mode to one of said alternate modes is required, activating said mode switch means; (f) if a switch from an alternate mode to said first mode is required, causing said microprocessor to reset by activating said resetting means by control means; (g) determining whether said resetting was triggered by said control means rather than by power-up, hardware faults, or a malfunction in the operation of the computer; and (h) if said resetting is determined to have been caused by said control means, causing said computer to bypass normal initialization routines during boot-up.

Claim 23

A method of operating a computer system with a multi-mode microprocessor that contains means to switch from a first mode to an alternate mode but no means to switch from said alternate mode to said first mode, and resetting means that causes boot-up in said first mode and initialization of said system, said method being so adapted as to enable a mixture of applications programs designed to run in the various modes of said microprocessor to be efficiently executed,said method comprising the steps of: (1) creating a record as to each application program that is loaded into said computer system, said record including an indication of the mode in which said program must be executed; (2) when execution of an application program by said microprocessor is required, checking said record and the current mode of said microprocessor to determine whether a mode switch is required; (3) if a mode switch from first mode to alternate mode is required, activating said mode switch means; (4) if a mode switch from an alternate mode to first mode is required, (a) providing means to determine that a resetting of said microprocessor was for mode switching purposes, (b) resetting the microprocessor, (c) determining from the means of (a) whether said resetting was for mode switching purposes, (d) if the determination in (c) is affirmative, causing said computer system to bypass normal initialization routines, and (5) executing said program.

Claim 24

A method of operating a computer system with a multi-mode microprocessor that contains means to switch from a first mode to an alternate mode but no means to switch from said alternate mode to said first mode, and resetting means that causes boot-up in said first mode and initialization of said system, said method being so adapted as to enable a mixture of applications programs designed to run in the various modes of said microprocessor to be efficiently executed,said method comprising the steps of: (1) creating a record as to each application program that is loaded into said computer system, said record including an indication of the mode in which said program must be executed; (2) when execution of an application program by said microprocessor is required, checking said record and the current mode of said microprocessor to determine whether a mode switch is required; (3) if a mode switch from first mode to alternate mode is required, activating said mode switch means; (4) if a mode switch from an alternate mode to first mode is required, (a) providing means to determine that a resetting of said microprocessor was for mode switching purposes, (b) resetting the microprocessor, (c) determining from the means of (a) whether said resetting was for mode switching purposes, (d) if the determination in (c) is affirmative, causing said computer system to bypass normal initialization routines, and (5) executing said program.

Claim 25

A medium with a series of instructions recorded thereon in such fashion as to be machine-readable into the memory of a digital computer based on a multi-mode microprocessor that contains means to switch only from a first mode to an alternate mode and resetting means that causes boot-up in said first mode and initialization of said system, said instructions being so adapted as to constitute an operating system for said computer system, said system being so adapted as to enable a mixture of applications programs designed to run in the various modes of said microprocessor to be efficiently executed by: (1) creating a record as to each application program that is loaded into said computer system, said record including an indication of the mode in which said progr-am must be executed; (2) when execution of an application program by said microprocessor is required, checking said record and the current mode of said microprocessor to determine whether a mode switch is required; (3) if a mode switch from first mode to alternate mode is required, activating said mode switch means; (4) if a mode switch from an alternate mode to said first mode is required, (a) providing means to determine that a resetting of said microprocessor was for mode switching purposes, (b) resetting said microprocessor, (c) determining from the means of (a) whether said resetting was for mode switching purposes, (d) if the determination in (c) is affirmative, causing said computer system to bypass normal initialization routines.

Claim 26

A medium with a series of instructions recorded thereon in such fashion as to be machine-readable into the memory of a digital computer based on a multi-mode microprocessor that contains means to switch only from a first mode to an alternate mode and resetting means that causes boot-up in said first mode and initialization of said system, said instructions being so adapted as to constitute an operating system for said computer system, said system being so adapted as to enable a mixture of applications programs designed to run in the various modes of said microprocessor to be efficiently executed by: (1) creating a record as to each application program that is loaded into said computer system, said record including an indication of the mode in which said progr-am must be executed; (2) when execution of an application program by said microprocessor is required, checking said record and the current mode of said microprocessor to determine whether a mode switch is required; (3) if a mode switch from first mode to alternate mode is required, activating said mode switch means; (4) if a mode switch from an alternate mode to said first mode is required, (a) providing means to determine that a resetting of said microprocessor was for mode switching purposes, (b) resetting said microprocessor, (c) determining from the means of (a) whether said resetting was for mode switching purposes, (d) if the determination in (c) is affirmative, causing said computer system to bypass normal initialization routines.

Claim 27

A method of operating a digital computer that utilizes a multi-mode microprocessor, the microprocessor operating in a first mode wherein memory locations within the computer are addressed by means of a binary address selector value that corresponds directly to a location in the physical nemery of the computer, and a second mode wherein memory loca- ti ns within the computer are addressed by means of a binary address selector value that designates a location in an intermediate mapping system where the desired physical memory address is located, the method comprising the steps of: (a) selecting a plurality of binary address selector values in the first mode which are compatible with the binary address selector values of the second mode that designate locations within the intermediate mapping system where operating system commands are located; (b) storing a value in the location within the intermediate mapping systems corresponding to each- selected binary address selector value which will designate the same location in the physical memory of the computer in the second mode as the selected binary address value designates in the first mode; and (c) storing a plurality of operating system routines in the physical memory of the computer such that the entry points for the routines are designated by the address selector values selected in step (a), thereby enabling each of the routines to be designated in either mode using a common address selector value.

Claim 28

A method of operating a digital computer that utilizes a multi-mode microprocessor, the microprocessor operating in a first mode wherein memory locations within the computer are addressed by means of a binary address selector value that corresponds directly to a location in the physical nemery of the computer, and a second mode wherein memory loca- ti ns within the computer are addressed by means of a binary address selector value that designates a location in an intermediate mapping system where the desired physical memory address is located, the method comprising the steps of: (a) selecting a plurality of binary address selector values in the first mode which are compatible with the binary address selector values of the second mode that designate locations within the intermediate mapping system where operating system commands are located; (b) storing a value in the location within the intermediate mapping systems corresponding to each- selected binary address selector value which will designate the same location in the physical memory of the computer in the second mode as the selected binary address value designates in the first mode; and (c) storing a plurality of operating system routines in the physical memory of the computer such that the entry points for the routines are designated by the address selector values selected in step (a), thereby enabling each of the routines to be designated in either mode using a common address selector value.

Claim 29

A method of processing interrupts in a digital computer system including a processing unit, a memory, and a multi-tasking operating system, the processing unit including an interrupt vector table for storing the memory addresses of operating system routines or application program routines for servicing interrupts, the method including the steps of: (a) for each interrupt serviced by an operating system routine, storing the address of the corresponding operating system interrupt service routine in a corresponding client list in a dispatcher routine in the operating system; (b) for each operating system interrupt service routine, storing the address of the dispatcher in the corresponding interrupt vector; (c) periodically examining the interrupt vector table to determine if any application programs have edited interrupt vectors to replace the address of the dispatcher with the address of an application program service routine; (d) for any edits located in step (c), placing the address of the application program interrupt service routine on top of the client list for the corresponding interrupt and restoring the interrupt vector value to point to the dispatcher; (e) upon receipt of an interrupt, successively transferring control to the interrupt service routines until one of the routines services the interrupt; and (f) upon termination of an application program that has edited the interrupt vector table, deleting the addresses of the interrupt service routines of the terminated program from the client lists .of the dispatcher and restoring the values of the interrupts as necessary to point to the dispatcher.

Claim 30

A method of processing interrupts in a digital computer system including a processing unit, a memory, and a multi-tasking operating system, the processing unit including an interrupt vector table for storing the memory addresses of operating system routines or application program routines for servicing interrupts, the method including the steps of: (a) for each interrupt serviced by an operating system routine, storing the address of the corresponding operating system interrupt service routine in a corresponding client list in a dispatcher routine in the operating system; (b) for each operating system interrupt service routine, storing the address of the dispatcher in the corresponding interrupt vector; (c) periodically examining the interrupt vector table to determine if any application programs have edited interrupt vectors to replace the address of the dispatcher with the address of an application program service routine; (d) for any edits located in step (c), placing the address of the application program interrupt service routine on top of the client list for the corresponding interrupt and restoring the interrupt vector value to point to the dispatcher; (e) upon receipt of an interrupt, successively transferring control to the interrupt service routines until one of the routines services the interrupt; and (f) upon termination of an application program that has edited the interrupt vector table, deleting the addresses of the interrupt service routines of the terminated program from the client lists .of the dispatcher and restoring the values of the interrupts as necessary to point to the dispatcher.