HD6417660 RENESAS [Renesas Technology Corp], HD6417660 Datasheet - Page 193

• Manufacturer Part Number: HD6417660
• Description: Renesas 32-Bit RISC Microcomputer
• Manufacturer: RENESAS [Renesas Technology Corp]

Section 4 Exception Handling
Exception handling is separate from normal program processing, and is performed by a routine
separate from the normal program. For example, if an attempt is made to execute an undefined
instruction code or an instruction protected by the CPU processing mode, a control function may
be required to return to the source program by executing the appropriate operation or to report an
abnormality and carry out end processing. In addition, a function to control processing requested
by LSI on-chip modules or an LSI external module to the CPU may also be required.
Transferring control to a user-defined exception handling routine and executing the process to
support the above functions are called exception handling. This LSI has two types of exceptions:
general exceptions and interrupts. The user can execute the required processing by assigning
exception handling routines corresponding to the required exception processing and then return to
the source program.
A reset input can terminate the normal program execution and pass control to the reset vector after
register initialization. This reset operation can also be regarded as an exception handling. This
section describes an overview of the exception handling operation. Here, general exceptions and
interrupts are referred to as exception handling. For interrupts, this section describes only the
process executed for interrupt requests. For details on how to generate an interrupt request, refer
to section 8, Interrupt Controller (INTC).
4.1
Register Descriptions
There are four registers for exception handling. A register with an undefined initial value should
be initialized by the software. Refer to section 27, List of Registers, for the register addresses and
register states in each process.
• TRAPA exception register (TRA)
• Exception event register (EXPEVT)
• Interrupt event register 2 (INTEVT2)
• Exception address register (TEA)
Rev. 1.00, 02/04, page 155 of 804