The V850 back end supports these function attributes:
interrupt
interrupt_handler
Use these attributes to indicate that the specified function is an interrupt handler. The compiler generates function entry and exit sequences suitable for use in an interrupt handler when either attribute is present.
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Licensed under the GNU Free Documentation License, Version 1.3.
https://gcc.gnu.org/onlinedocs/gcc-7.3.0/gcc/V850-Function-Attributes.html