US5481726A
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Information processing system having a plurality of processors
Assignee: Mitsubishi Electric Corp
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Filing: 1993-08-30
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Granted: 1996-01-02
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Expires: 2013-08-30
Abstract
Abstract An information processing system including processors, and an interrupt controller responsive to an interrupt request signal from the processors for executing an interrupt process control of processes carried out by the processors. The interrupt controller includes an interrupt process execution device that does not have a multiple interrupt processing function, and an interrupt acceptance device. The interrupt acceptance device has an interrupt reservation signal input terminal, and responds to an interrupt request signal for making determination whether an interrupt is permitted. If interrupt is permitted, an interrupt request generation signal is applied to a corresponding interrupt request generation signal input terminal of the interrupt process execution device. Each of the processors includes an interrupt request signal output circuit and a processing circuit. The interrupt reservation signal output circuit generates and provides to an interrupt reservation signal input terminal of the interrupt acceptance device an interrupt reservation signal prior to an output of an interrupt request signal from the interrupt request signal output circuit. By applying an interrupt reservation signal to the interrupt reservation signal input terminal from the particular processor, an interrupt request signal generated from another processor can not be accepted during the time thereof.
Inventors
- 👤 Satoshi Kumaki
- 👤 Kazuya Ishihara
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 11:35
CPC Classifications
G; G06; G06F; G06F13/00; G06F13/14; G06F13/20; G06F13/24
Claims Analysis
Total Claims: 27
Claim 1
Independent Claim
506 words
An information processing system comprising: a plurality of information processors (92, 94, 96), each capable of executing an individual process; interrupt control means (20) responsive to an interrupt request signal provided from said plurality of information processors for controlling execution means (30) without a multiple interrupt process function, including a plurality of interrupt request generation signal input terminals (41, 47, 51) to which an interrupt request generation signal is applied, a plurality of interrupt request acceptance signal output terminals (43, 49, 53) provided corresponding to said plurality of interrupt request generation signal input terminals, an interrupt request input acceptance signal output terminal (70), and an interrupt process end signal output terminal (72), responsive to a first interrupt request generation signal applied to at least one of said plurality of interrupt request generation signal input terminals for providing an interrupt acceptance signal to a corresponding said interrupt request acceptance signal output terminal and an interrupt request input acceptance signal to said interrupt request input acceptance signal output terminal (70) and initiating execution of a predetermined interrupt process, and for providing an interrupt process end signal to said interrupt process end signal output terminal (72) when said predetermined interrupt is completed; interrupt acceptance means (32, 34, 36) including a plurality of interrupt request signal input terminals (40, 44, 46, 50) receiving externally applied interrupt request signals corresponding to a different one of said plurality of interrupt request generation signal input terminals (41, 47, 51), said plurality of interrupt request signal input terminals including first interrupt request signal input terminals (40, 46, 50) and an interrupt reservation signal input terminal (44) for receiving an externally applied interrupt reservation signal, said interrupt acceptance means being responsive to an interrupt request signal applied to said interrupt request signal input terminals (40, 44, 46, 50) for making a determination whether an interrupt is permitted or not according to a condition determined on the basis of said interrupt request input acceptance signal, said interrupt process end signal, and said interrupt reservation signal, and if an interrupt is permitted, outputting and providing an interrupt request generation signal to a corresponding interrupt request generation signal input terminal (41, 47, 51) of said interrupt process execution means; wherein each of said plurality of information processors comprises interrupt request signal output means (98) for generating and applying to a corresponding one of said plurality of interrupt request signal input terminals of said interrupt control means an interrupt request signal when an interrupt is desired, and processing means (120) connected to a corresponding said interrupt request acceptance signal output terminal (100) for executing a predetermined process in response to an interrupt request acceptance signal provided from said interrupt control means and the information processor connected to said first interrupt request signal input terminal further comprises interrupt reservation signal output means (128, 148) for outputting and applying to said interrupt reservation signal input terminal of said interrupt acceptance means an interrupt reservation signal prior to an output of said interrupt request signal from said interrupt request signal output means.
Claim 2
Dependent Claim
506 words
An information processing system comprising: a plurality of information processors (92, 94, 96), each capable of executing an individual process; interrupt control means (20) responsive to an interrupt request signal provided from said plurality of information processors for controlling execution means (30) without a multiple interrupt process function, including a plurality of interrupt request generation signal input terminals (41, 47, 51) to which an interrupt request generation signal is applied, a plurality of interrupt request acceptance signal output terminals (43, 49, 53) provided corresponding to said plurality of interrupt request generation signal input terminals, an interrupt request input acceptance signal output terminal (70), and an interrupt process end signal output terminal (72), responsive to a first interrupt request generation signal applied to at least one of said plurality of interrupt request generation signal input terminals for providing an interrupt acceptance signal to a corresponding said interrupt request acceptance signal output terminal and an interrupt request input acceptance signal to said interrupt request input acceptance signal output terminal (70) and initiating execution of a predetermined interrupt process, and for providing an interrupt process end signal to said interrupt process end signal output terminal (72) when said predetermined interrupt is completed; interrupt acceptance means (32, 34, 36) including a plurality of interrupt request signal input terminals (40, 44, 46, 50) receiving externally applied interrupt request signals corresponding to a different one of said plurality of interrupt request generation signal input terminals (41, 47, 51), said plurality of interrupt request signal input terminals including first interrupt request signal input terminals (40, 46, 50) and an interrupt reservation signal input terminal (44) for receiving an externally applied interrupt reservation signal, said interrupt acceptance means being responsive to an interrupt request signal applied to said interrupt request signal input terminals (40, 44, 46, 50) for making a determination whether an interrupt is permitted or not according to a condition determined on the basis of said interrupt request input acceptance signal, said interrupt process end signal, and said interrupt reservation signal, and if an interrupt is permitted, outputting and providing an interrupt request generation signal to a corresponding interrupt request generation signal input terminal (41, 47, 51) of said interrupt process execution means; wherein each of said plurality of information processors comprises interrupt request signal output means (98) for generating and applying to a corresponding one of said plurality of interrupt request signal input terminals of said interrupt control means an interrupt request signal when an interrupt is desired, and processing means (120) connected to a corresponding said interrupt request acceptance signal output terminal (100) for executing a predetermined process in response to an interrupt request acceptance signal provided from said interrupt control means and the information processor connected to said first interrupt request signal input terminal further comprises interrupt reservation signal output means (128, 148) for outputting and applying to said interrupt reservation signal input terminal of said interrupt acceptance means an interrupt reservation signal prior to an output of said interrupt request signal from said interrupt request signal output means.
Claim 3
Dependent Claim
224 words
The information processing system according to claim 1, wherein said plurality of interrupt request signal input terminals comprise a single said first interrupt request signal input terminal, and a second interrupt request signal input terminal, said interrupt acceptance means comprises first interrupt request generation signal output means provided corresponding to said first interrupt request signal input terminal (40), and responsive to an interrupt request signal applied to said first interrupt request signal input terminal (40) for making a determination whether said interrupt process execution means can accept an interrupt or not according to said interrupt request input acceptance signal and said interrupt process end signal, and if acceptable, outputting and applying to a corresponding interrupt request generation signal input terminal (41) of said interrupt process execution means an interrupt request generation signal and second interrupt request generation signal output means (34) provided corresponding to said second interrupt request signal input terminal (46), and responsive to an interrupt request signal applied to said second interrupt request signal input terminal for making a determination whether an interrupt is permitted or not according to said interrupt request input acceptance signal, said interrupt process end signal, and said interrupt reservation signal, and if permitted, outputting and applying to a corresponding interrupt request generation signal output terminal (47) of said interrupt process execution means an interrupt request generation signal.
Claim 4
Dependent Claim
104 words
The information processing system according to claim 2, wherein said first and second interrupt request generation signal output means comprises holding means (54, 60, 66) responsive to said interrupt request input acceptance signal and said interrupt process end signal for holding and providing information indicating whether said interrupt process execution means is during execution of an interrupt process, and logic circuit means (56, 62, 68) to carry out a predetermined logic calculation on an interrupt request signal applied via corresponding said interrupt request signal input terminal and an output of said holding means for providing the calculation result as said interrupt request generation signal.
Claim 5
Dependent Claim
141 words
The information processing system according to claim 3, wherein said interrupt request input acceptance signal, said interrupt request signal, and said interrupt request generation signal are all of negative logics, wherein said holding means of said first interrupt request generation signal output means comprises means for inverting the level of said interrupt request input acceptance signal, and a first set-reset type flipflop having the set input and the reset input connected to an output of said inverting means and said interrupt process end signal output terminal of said interrupt process execution means, respectively, and said logic circuit means of said first interrupt request generation signal output means comprises a first logic sum gate circuit having one input connected to the output of said first set-reset type flipflop and the other input connected to said first interrupt request signal input terminal, respectively.
Claim 6
Dependent Claim
142 words
The information processing system according to claim 4, wherein said interrupt reservation signal comprises a negative logic, said holding means of said second interrupt request generation signal output means comprises a NAND gate circuit having one input connected to said interrupt request input acceptance signal output terminal and the other input connected to said interrupt reservation signal input terminal, and a second set-reset type flipflop having the set input connected to an output of said NAND gate circuit and the reset input connected to said interrupt process end signal output terminal of said interrupt process execution means, said logic circuit means of said second interrupt generation signal output means comprises a second logic sum gate circuit having one input connected to an output of said second set-reset type flipflop and the other input connected to said second interrupt request signal input terminal.
Claim 7
Dependent Claim
158 words
The information processing system according to claim 3, wherein said interrupt request input acceptance signal, said interrupt request signal, said interrupt request generation signal, and said interrupt reservation signal all are of negative logics, said holding means of said second interrupt request generation signal output means comprises a NAND gate circuit having one input connected to said interrupt request input acceptance signal output terminal and the other input connected to said interrupt reservation signal input terminal, and a set-reset type flipflop having the set input connected to an output of said NAND gate circuit and the reset input connected to said interrupt process end signal output terminal of said interrupt process execution means, and said logic circuit means of said second interrupt request generation signal output means comprises a logic sum gate circuit having one input connected to an output of said set-reset type flipflop, and the other input connected to said second interrupt request signal input terminal.
Claim 8
Dependent Claim
68 words
The information processing system according to claim 1, wherein said interrupt reservation signal output means of said information processor connected to said first interrupt request signal input terminal comprises means for providing an interrupt reservation signal after an elapse of a predetermined time since an interrupt request acceptance signal is applied from said interrupt request acceptance signal output terminal corresponding to said first interrupt request signal input terminal.
Claim 9
Dependent Claim
139 words
An information processing system according to claim 7, wherein said means for providing said interrupt reservation signal after elapse of said predetermined time period operates in response to a clock signal of a predetermined frequency, and comprises storage means for storing a number defining said predetermined time period, means responsive to said clock signal for incrementing contents thereof at a constant rate, means responsive to said interrupt request acceptance signal for resetting the contents of said incrementing means, match detection means for detecting a match between the contents of said storage means and the contents of said incrementing means for generating a match detection signal, and means for initiating output of said interrupt reservation signal in response to said match detection signal, and for suppressing output of said interrupt reservation signal in response to said interrupt request acceptance signal.
Claim 10
Dependent Claim
52 words
The information processing system according to claim 8, wherein said means for resetting comprises means for resetting the contents of said incrementing means selectively responding to either of said interrupt request acceptance signal and a reset signal applied from said processing means dependent on a select signal provided from said processing means.
Claim 11
Dependent Claim
81 words
The information processing system according to claim 8, wherein said interrupt request signal and said interrupt request acceptance signal are both of a negative logic, and said means for initiating and suppressing output of said interrupt reservation signal comprises inverting means for inverting the level of said interrupt request acceptance signal, and a set-reset type flipflop including a set input connected to the output of said inverting means and a reset input connected to the output of said match detection means.
Claim 12
Dependent Claim
166 words
The information processing system according to claim 1, wherein said processing means of said information processor connected to said first interrupt request signal input terminal comprises means for providing a predetermined first address signal in response to an interrupt request acceptance signal applied from said interrupt request acceptance signal output terminal corresponding to said first interrupt request signal input terminal, and means for providing a predetermined second address signal after elapse of a predetermined time period since an interrupt request acceptance signal is provided from said interrupt request acceptance signal output terminal corresponding to said first interrupt request signal input terminal, and wherein said interrupt reservation signal output means of said information processor connected to said first interrupt request signal input terminal comprises decode means for decoding an address signal applied from said processing means to initiate output of said interrupt reservation signal in response to said second address signal and to suppress output of said interrupt reservation signal in response to said first address signal.
Claim 13
Dependent Claim
26 words
The information processing system according to claim 1, wherein said interrupt control means and said plurality of information processors are formed on a single common substrate.
Claim 14
Dependent Claim
328 words
In an information processing system comprising interrupt control means (30) having a plurality of interrupt request signal input terminals (40, 44, 46, 50) including first interrupt request signal input terminals (40, 46, 500) each for receiving an externally applied interrupt request signal, and an interrupt reservation signal input terminal (44) for receiving an externally applied interrupt reservation signal, and a plurality of interrupt request acceptance signal output terminals (42, 48, 52) provided corresponding to a plurality of interrupt request signal input terminals, and responding to the first interrupt request signal applied to said plurality of interrupt request signal input terminals when an interrupt reservation signal is not applied to accept an interrupt, and responding to only an interrupt request generation signal applied to said first interrupt request signal input terminal to accept an interrupt when an interrupt reservation signal is applied, for providing an interrupt acceptance signal to a corresponding said interrupt request acceptance signal output terminal to initiate execution of a predetermined interrupt process, and to end said predetermined interrupt process by providing an interrupt process end signal to said interrupt process end signal output terminal (72); an information processor connected to said first interrupt request signal input terminal and said interrupt reservation signal input terminal, comprising: interrupt request signal output means (98) for generating and applying to said first interrupt request signal input terminal of said interrupt control means an interrupt request signal when a predetermined condition is met, processing means (120) connected to one of said interrupt request acceptance signal output terminals (100) corresponding to said first interrupt request signal input terminal, and responsive to an interrupt request acceptance signal provided from said interrupt control means for executing a predetermined process, and interrupt reservation signal output means (128, 148) for outputting and applying to said interrupt reservation signal input terminal of said interrupt control means an interrupt reservation signal prior to an output of said interrupt request signal from said interrupt request signal output means.
Claim 15
Dependent Claim
328 words
In an information processing system comprising interrupt control means (30) having a plurality of interrupt request signal input terminals (40, 44, 46, 50) including first interrupt request signal input terminals (40, 46, 500) each for receiving an externally applied interrupt request signal, and an interrupt reservation signal input terminal (44) for receiving an externally applied interrupt reservation signal, and a plurality of interrupt request acceptance signal output terminals (42, 48, 52) provided corresponding to a plurality of interrupt request signal input terminals, and responding to the first interrupt request signal applied to said plurality of interrupt request signal input terminals when an interrupt reservation signal is not applied to accept an interrupt, and responding to only an interrupt request generation signal applied to said first interrupt request signal input terminal to accept an interrupt when an interrupt reservation signal is applied, for providing an interrupt acceptance signal to a corresponding said interrupt request acceptance signal output terminal to initiate execution of a predetermined interrupt process, and to end said predetermined interrupt process by providing an interrupt process end signal to said interrupt process end signal output terminal (72); an information processor connected to said first interrupt request signal input terminal and said interrupt reservation signal input terminal, comprising: interrupt request signal output means (98) for generating and applying to said first interrupt request signal input terminal of said interrupt control means an interrupt request signal when a predetermined condition is met, processing means (120) connected to one of said interrupt request acceptance signal output terminals (100) corresponding to said first interrupt request signal input terminal, and responsive to an interrupt request acceptance signal provided from said interrupt control means for executing a predetermined process, and interrupt reservation signal output means (128, 148) for outputting and applying to said interrupt reservation signal input terminal of said interrupt control means an interrupt reservation signal prior to an output of said interrupt request signal from said interrupt request signal output means.
Claim 16
Dependent Claim
37 words
The information processor according to claim 13, wherein said interrupt reservation signal output means comprises means for providing said interrupt reservation signal after elapse of a predetermined time period since said interrupt request acceptance signal is applied.
Claim 17
Dependent Claim
136 words
The information processor according to claim 13, wherein said means for providing said interrupt reservation signal after elapse of said predetermined time period operates in response to a clock signal of a predetermined frequency, and comprises storage means for storing a number defining said predetermined time period, means for incrementing contents thereof at a constant rate in response to said clock signal, means responsive to said interrupt request acceptance signal for resetting the contents of said increment means, match detection means for detecting match between contents of said storage means and contents of said increment means for generating a match detection signal, and means for initiating output of said interrupt reservation signal in response to said match detection signal, and for suppressing output of said interrupt reservation signal in response to said interrupt request acceptance signal.
Claim 18
Dependent Claim
52 words
The information processor according to claim 15, wherein said means for resetting comprises means for resetting the contents of said increment means in selective response to either of said interrupt request acceptance signal and a reset signal applied from said processing means dependent on a select signal applied from said processing means.
Claim 19
Dependent Claim
80 words
The information processor according to claim 15, wherein said interrupt request signal and said interrupt request acceptance signal are both of a negative logic, wherein said means for initiating and suppressing an output of said interrupt reservation signal comprises invert means for inverting the level of said interrupt request acceptance signal, a set-reset type flipflop having a set input connected to the output of said invert means and a reset input connected to the output of said match detection means.
Claim 20
Dependent Claim
120 words
The information processor according to claim 13, wherein said processing means comprises means for providing a predetermined first address signal in response to an interrupt request acceptance signal applied from said interrupt request acceptance signal output terminal, and means for providing a predetermined second address signal after elapse of a predetermined time period since an interrupt request acceptance signal is applied from said interrupt request acceptance signal output terminal, and said interrupt reservation signal output means comprises decode means for decoding an address signal applied from said processing means to initiate output of said interrupt reservation signal in response to said second address signal and to suppress output of said interrupt reservation signal in response to said first address signal.
Claim 21
Dependent Claim
398 words
In an information processing system including a plurality of information processors, each capable of executing individual processes; an interrupt controller responsive to an interrupt request signal provided from said plurality of information processors for controlling execution of a process carried out by said plurality of information processors, said interrupt controller comprising interrupt process execution means (30) without a multiple interrupt processing function including a plurality of interrupt request generation signal input terminals (41, 47, 51) to which an interrupt request generation signal is applied, a plurality of interrupt request acceptance signal output terminals (43, 49, 53) provided corresponding to said plurality of interrupt request generation signal input terminals, an interrupt request input acceptance signal output terminal (70), and an interrupt process end signal output terminal (72), and responsive to the first interrupt request generation signal applied to said plurality of interrupt request generation signal input terminals to provide an interrupt request acceptance signal and an interrupt request input acceptance signal to a corresponding said interrupt request acceptance signal output terminal and said interrupt request input acceptance signal output terminal, respectively, for initiating execution of a predetermined interrupt process, and to end said predetermined interrupt process by providing an interrupt process end signal to said interrupt process end signal output terminal, and interrupt acceptance means (32, 34, 36) including a plurality of interrupt request signal input terminals (40, 44, 46, 50) connected to said plurality of information processors for receiving an interrupt request signal, each corresponding to a different one of said plurality of interrupt request generation signal input terminals, said plurality of interrupt request signal input terminals including first interrupt request signal input terminal (40, 46, 50) and an interrupt reservation signal input terminal (44) to be connected to one of said plurality of information processors for receiving an interrupt reservation signal, and provided in relation to said interrupt request signal input terminals, and responsive to an interrupt request signal applied to said interrupt request signal input terminals for making a determination whether an interrupt is permitted or not according to a condition determined on the basis of said interrupt request input acceptance signal, said interrupt process end signal, and said interrupt reservation signal, and if an interrupt is permitted, outputting and applying to a corresponding interrupt request generation signal input terminal (one of 41, 47, 51) of said interrupt process execution means an interrupt request generation signal.
Claim 22
Dependent Claim
398 words
In an information processing system including a plurality of information processors, each capable of executing individual processes; an interrupt controller responsive to an interrupt request signal provided from said plurality of information processors for controlling execution of a process carried out by said plurality of information processors, said interrupt controller comprising interrupt process execution means (30) without a multiple interrupt processing function including a plurality of interrupt request generation signal input terminals (41, 47, 51) to which an interrupt request generation signal is applied, a plurality of interrupt request acceptance signal output terminals (43, 49, 53) provided corresponding to said plurality of interrupt request generation signal input terminals, an interrupt request input acceptance signal output terminal (70), and an interrupt process end signal output terminal (72), and responsive to the first interrupt request generation signal applied to said plurality of interrupt request generation signal input terminals to provide an interrupt request acceptance signal and an interrupt request input acceptance signal to a corresponding said interrupt request acceptance signal output terminal and said interrupt request input acceptance signal output terminal, respectively, for initiating execution of a predetermined interrupt process, and to end said predetermined interrupt process by providing an interrupt process end signal to said interrupt process end signal output terminal, and interrupt acceptance means (32, 34, 36) including a plurality of interrupt request signal input terminals (40, 44, 46, 50) connected to said plurality of information processors for receiving an interrupt request signal, each corresponding to a different one of said plurality of interrupt request generation signal input terminals, said plurality of interrupt request signal input terminals including first interrupt request signal input terminal (40, 46, 50) and an interrupt reservation signal input terminal (44) to be connected to one of said plurality of information processors for receiving an interrupt reservation signal, and provided in relation to said interrupt request signal input terminals, and responsive to an interrupt request signal applied to said interrupt request signal input terminals for making a determination whether an interrupt is permitted or not according to a condition determined on the basis of said interrupt request input acceptance signal, said interrupt process end signal, and said interrupt reservation signal, and if an interrupt is permitted, outputting and applying to a corresponding interrupt request generation signal input terminal (one of 41, 47, 51) of said interrupt process execution means an interrupt request generation signal.
Claim 23
Dependent Claim
212 words
The interrupt controller according to claim 19, wherein said plurality of interrupt request signal input terminals comprise a single said first interrupt request signal input terminal, and a second interrupt request signal input terminal, said interrupt acceptance means comprises a first interrupt request generation signal output means provided corresponding to said interrupt request signal input terminal, and responsive to an interrupt request signal applied to said first interrupt request signal input terminal for making determination whether said interrupt process execution means can accept an interrupt according said interrupt request input acceptance signal and said interrupt process end signal, and if acceptable, outputting and applying, to a corresponding interrupt request generation signal input terminal of said interrupt process execution means an interrupt request generation signal, and second interrupt request generation signal output means provided corresponding to said second interrupt request signal input terminal, and responsive to an interrupt request signal applied to said second interrupt request signal input terminal for making determination whether an interrupt is permitted or not according to said interrupt request input acceptance signal, said interrupt process end signal, and said interrupt reservation signal, and if permitted, outputting and applying to a corresponding interrupt request generation signal input terminal of said interrupt process execution means an interrupt request generation signal.
Claim 24
Dependent Claim
96 words
The interrupt controller according to claim 20, wherein said first and second interrupt request generation signal output means comprises holding means responsive to said interrupt request input acceptance signal and said interrupt process end signal for holding and providing information indicating whether said interrupt process execution means is during execution of an interrupt process, and logic circuit means for applying a predetermined logic calculation on an interrupt request signal applied via corresponding said interrupt request signal input terminal and an output of said holding means for providing a calculation result as said interrupt request generation signal.
Claim 25
Dependent Claim
139 words
The interrupt controller according to claim 21, wherein said interrupt request input acceptance signal, said interrupt request signal, and said interrupt request generation signal are all of a negative logic, said holding means of said first interrupt request generation signal output means comprises means for inverting the level of said interrupt request input acceptance signal, and a first set-reset type flipflop having the set input connected to an output of said invert means and the reset input connected to said interrupt process end signal output terminal of said interrupt process execution means, and said logic circuit means of said first interrupt request generation signal output means comprises a first logic sum gate circuit having one input connected to an output of said first set-reset type flipflop, and the other input connected to said first interrupt request signal input terminal.
Claim 26
Dependent Claim
142 words
The interrupt controller according to claim 22, wherein said interrupt reservation signal is of a negative logic, said holding means of said second interrupt request generation signal output means comprises a NAND gate circuit having one input connected to said interrupt request input acceptance signal output terminal and the other input to said interrupt reservation signal input terminal, and a second set-reset type flipflop having the set input connected to an output of said NAND gate circuit and the reset input connected to said interrupt process end signal output terminal of said interrupt process execution means, said logic circuit means of said second interrupt request generation signal output means comprises a second logic sum gate circuit having one input connected to an output of said second set-reset type flipflop, and the other input connected to said second interrupt request signal input terminal.
Claim 27
Dependent Claim
156 words
The interrupt controller according to claim 21, wherein said interrupt request input acceptance signal, said interrupt request signal, said interrupt request generation signal, and said interrupt reservation signal are all of a negative logic, said holding means of said second interrupt request generation signal output means comprises a NAND gate circuit having one input connected to said interrupt request input acceptance signal output terminal and the other input to said interrupt reservation signal input terminal, and a set-reset type flipflop having the set input connected to an output of said NAND gate circuit and the reset input connected to said interrupt process end signal output terminal of said interrupt process execution means, and said logic control means of said second interrupt request generation signal output means comprises a logic sum gate circuit having one input connected to an output of said reset-reset type flipflop and the other input to said second interrupt request signal input terminal.
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