R5F72115D160FPV datasheet(163/1228 Pages) RENESAS

163 / 1228 page

Section 6 Interrupt Controller (INTC)

Rev. 2.00 May. 08, 2008 Page 139 of 1200

REJ09B0344-0200

6.8.4

There are two register bank exceptions (register bank errors): register bank overflow and register

bank underflow.

(1)

This exception occurs if, after data has been saved to all of the register banks, an interrupt for

which register bank use is allowed is accepted by the CPU, and the BOVE bit in the bank number

bank.

(2)

This exception occurs if the RESBANK (restore from register bank) instruction is executed when

no data has been saved to the register banks. In this case, the values of R0 to R14, GBR, MACH,

MACL, and PR do not change. In addition, the bank number bit (BN) value in the bank number

6.8.5

When a register bank error occurs, register bank error exception handling starts. When this

happens, the CPU operates as follows:

1. The exception service routine start address which corresponds to the register bank error that

occurred is fetched from the exception handling vector table.

2. The status register (SR) is saved to the stack.

3. The program counter (PC) is saved to the stack. The PC value saved is the start address of the

instruction to be executed after the last executed instruction for a register bank overflow, and

the start address of the executed RESBANK instruction for a register bank underflow. To

prevent multiple interrupts from occurring at a register bank overflow, the interrupt priority

level that caused the register bank overflow is written to the interrupt mask level bits (I3 to I0)

of the status register (SR).

4. Program execution starts from the exception service routine start address.

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