SH7708 datasheet(100/633 Pages) RENESAS

100 / 633 page

A basic exception processing sequence consists of the following operations:

• The contents of the PC and SR are saved in the SPC and SSR, respectively.

• The block (BL) bit in SR is set to 1, masking any subsequent exceptions.

• The mode (MD) bit in SR is set to 1 to place the SH7708 Series in privileged mode.

• The register bank (RB) bit in SR is set to 1.

• An encoded value identifying the exception event is written to bits 11–0 of the exception event

(EXPEVT) or interrupt event (INTEVT) register.

• Instruction execution jumps to the designated exception processing vector address to invoke

the handler routine.

4.2.2

Exception Handling Vector Addresses

The reset vector address is fixed at H'A0000000. The other three events are assigned offsets from

the vector base address by software. Translation lookaside buffer (TLB) miss exceptions have an

offset from the vector base address of H'00000400. The vector address offset for general exception

events other than TLB miss exceptions is H'00000100. The interrupt vector address offset is

H'00000600. The vector base address is loaded into the vector base register (VBR) by software.

The vector base address should reside in P1 or P2 fixed physical address space. Figure 4.1 shows

the relationship between the vector base address, the vector offset, and the vector table.

VBR

+ Vector offset

H'A000 0000

Vector table

Figure 4.1 Vector Table

In table 4.2, exceptions and their vector addresses are listed by exception type, instruction

completion status, relative acceptance priority, relative order of occurrence within an instruction

execution sequence and vector address for exceptions and their vector addresses.

SH7708 Datasheet(PDF) 100 Page - Renesas Technology Corp