RX610 Group
9. Exceptions
R01UH0032EJ0120 Rev.1.20
Page 204 of 1006
Feb 20, 2013
9.1.1
Undefined Instruction Exception
An undefined instruction exception occurs when execution of an undefined instruction (an instruction not implemented)
is detected.
9.1.2
Privileged Instruction Exception
A privileged instruction exception occurs when execution of a privileged instruction is detected while operation is in user
mode. Privileged instructions can only be executed in supervisor mode.
9.1.3
Floating-Point Exceptions
Floating-point exceptions include the five specified in the IEEE754 standard, namely overflow, underflow, inexact,
division-by-zero, and invalid operation, and a further floating-point exception that is generated on the detection of
unimplemented processing. The exception processing of floating-point exceptions is masked when the EX, EU, EZ, EO,
or EV bit in FPSW is 0.
9.1.4
Reset
A reset through input of the reset signal to the CPU causes the exception request. This has the highest priority of any
exception and is always accepted.
9.1.5
Non-Maskable Interrupt
The non-maskable interrupt is generated by input of the non-maskable interrupt signal to the CPU and is only used when
a fatal fault is considered to have occurred in the system. Never end the exception handling routine for the non-maskable
interrupt with an attempt to return to the program that was being executed at the time of interrupt generation.
9.1.6
Interrupts
Interrupts are generated by the input of interrupt signals to the CPU. The interrupt with the highest priority can be
selected for handling as a fast interrupt. The exception processing of interrupts is masked when the I bit in the PSW is 0.
9.1.7
Unconditional Trap
An unconditional trap is generated when the INT or BRK instruction is executed.