Abstract: An information processor has at least one interface unit by which the processor is coupled to a peripheral equipment. The interface unit can selectively generate either a first mode signal or a second mode signal when the processor performs and interruption operation according to request from the peripheral equipment. When the processor performs the interruption operation in response to the first mode signal, a stack operation for saving information necessary to restart a program execution which is stopped by the interruption to a stack memory is performed before start of the interruption operation. While the processor can perform the interruption operation in response to the second mode signal without the stack operation, whereby an improved processor with less overhead can be provided.

Abstract: An information processor has at least one interface unit by which the processor is coupled to a peripheral equipment. The interface unit can selectively generate either a first mode signal or a second mode signal when the processor performs an interruption operation according to request from the peripheral equipment. When the processor performs the interruption operation in response to the first mode signal, a stack operation for saving information necessary to restart a program execution which is stopped by the interruption to a stack memory is performed before start of the interruption operation. While the processor can perform the interruption operation in response to the second mode signal without the stack operation, whereby an improved processor with less overhead can be provided.

Abstract: An information processor has at least one interface unit by which the processor is coupled to peripheral equipment. The interface unit can selectively generate either a first mode signal or a second mode signal when the processor performs an interruption operation according to request from the peripheral equipment. When the processor performs the interruption operation in response to the first mode signal, a stack operation for saving information necessary to restart execution of a program which is stopped by the interruption in a stack memory is performed before the start of the interruption operation. The processor can perform the interruption operation in response to the second mode signal without the stack operation, providing an improved processor with less overhead. The two interruption mode technique is described in a number of applications, including D/A conversion, serial data transmission and reception, and operation of computer peripheral devices.

Abstract: A data processor comprises a memory for storing programs and various data, an execution unit coupled to the memory to execute processing based upon the programs stored in the memory, a plurality of count registers carrying out a count operation at a predetermined interval, respectively and accessible by the execution unit, and a corresponding number of memory registers for temporarily storing a content of the corresponding count register, respectively. Further, a control circuit is provided for each of the memory registers to respond to a store instruction signal to the memory and a memory control signal from the execution unit for controlling an operation of the memory register storing the content of the count register.