SH7261 datasheet(193/1348 Pages) RENESAS

193 / 1348 page

Section 6 Interrupt Controller (INTC)

Rev. 2.00 Sep. 07, 2007 Page 161 of 1312

REJ09B0320-0200

6.8.3

Save and Restore Operations after Saving to All Banks

If an interrupt occurs and usage of the register banks is enabled for the interrupt accepted by the

CPU in a state where saving has been performed to all register banks, automatic saving to the

stack is performed instead of register bank saving if the BOVE bit in the bank number register

(IBNR) is cleared to 0. If the BOVE bit in IBNR is set to 1, register bank overflow exception

occurs and data is not saved to the stack.

Save and restore operations when using the stack are as follows:

(1)

Saving to Stack

1. The status register (SR) and program counter (PC) are saved to the stack during interrupt

exception handling.

2. The contents of the banked registers (R0 to R14, GBR, MACH, MACL, and PR) are saved to

the stack. The registers are saved to the stack in the order of MACL, MACH, GBR, PR, R14,

R13, …, R1, and R0.

3. The register bank overflow bit (BO) in SR is set to 1.

4. The bank number bit (BN) value in the bank number register (IBNR) remains set to the

maximum value of 15.

(2)

Restoration from Stack

When the RESBANK (restore from register bank) instruction is executed with the register bank

overflow bit (BO) in SR set to 1, the CPU operates as follows:

1. The contents of the banked registers (R0 to R14, GBR, MACH, MACL, and PR) are restored

from the stack. The registers are restored from the stack in the order of R0, R1, …, R13, R14,

PR, GBR, MACH, and MACL.

2. The bank number bit (BN) value in the bank number register (IBNR) remains set to the

maximum value of 15.

SH7261 Datasheet(PDF) 193 Page - Renesas Technology Corp