Fujitsu MB90390 Series Hardware Manual page 83

F
Enable FF
Cause FF
■ Software Interrupts
Interrupts requested by executing the INT instruction are software interrupts. An interrupt request by the
INT instruction does not have an interrupt request or enable flag. An interrupt request is issued always by
executing the INT instruction.
No interrupt level is assigned to the INT instruction. Therefore, ILM is not updated when the INT
instruction is used. Instead, the I flag is cleared and the continuing interrupt requests are suspended.
Save
■ Extended Intelligent I/O Service (EI
The extended intelligent I/O service automatically transfers data between an internal resource and memory.
This processing is traditionally performed by an interrupt processing program, but the EI
to be transferred in a manner similar to a DMA (direct memory access) operation.
To activate the extended intelligent I/O service function from an internal resource, the interrupt control
register (ICR) of the interrupt controller must have an extended intelligent I/O service enable flag (ISE).
The extended intelligent I/O service is started when an interrupt request occurs with "1" specified in the
ISE flag.
To generate a normal interrupt using a hardware interrupt request, set the ISE flag to "0".
Figure 3.1-1 Overview of Hardware Interrupts
Register file
Microcode
IR
M C - 1 6 LX . CPU
2
Peripheral
AND
Figure 3.1-2 Overview of Software Interrupts
Register file
Microcode
IR
2
M C - 1 6 LX · C P U
F
RAM
2
PS I
ILM
Check Comparator
Interrupt
controller
PS I S
B unit
Queue Fetch
Instruction bus
OS)
CHAPTER 3 INTERRUPTS
PS :Processor status
I :Interrupt enable flag
ILM :Interrupt level mask register
IR :Instruction register
B unit :Bus interface unit
PS :Processor status
I :Interrupt enable flag
S :Stack flag
IR :Instruction register
B unit :Bus interface unit
2
OS enables data
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