PowerPC 603 RISC Microprocessor Technical Summary

21

Table 2. Exceptions and Conditions

Exception

Type

Vector Offset

(hex)

Causing Conditions

Reserved

00000

—

System reset

00100

A system reset is caused by the assertion of either SRESET or HRESET.

Machine check

00200

A machine check is caused by the assertion of the TEA signal during a data bus transaction,

assertion of MCP, or an address or data parity error.

DSI

00300

The cause of a DSI exception can be determined by the bit settings in the DSISR, listed as

follows:

1 Set if the translation of an attempted access is not found in the primary hash table entry

group (HTEG), or in the rehashed secondary HTEG, or in the range of a DBAT register;

otherwise cleared.

4 Set if a memory access is not permitted by the page or DBAT protection mechanism;

otherwise cleared.

5 Set if the access was to an I/O segment (SR[T] =1) by an eciwx, ecowx, lwarx, or

stwcx. instruction; otherwise cleared.

6 Set for a store operation and cleared for a load operation.

11 Set if eciwx or ecowx is used and EAR[E] is cleared.

ISI

00400

An ISI exception is caused when an instruction fetch cannot be performed for any of the

following reasons:

•

The effective (logical) address cannot be translated. That is, there is a page fault for this

portion of the translation, so an ISI exception must be taken to load the PTE (and

possibly the page) into memory.

•

The fetch access is to a direct-store segment.

•

The fetch access violates memory protection. If the key bits (Ks and Kp) in the segment

register and the PP bits in the PTE are set to prohibit read access, instructions cannot be

fetched from this location.

External

interrupt

00500

An external interrupt is caused when MSR[EE] = 1 and the INT signal is asserted.

Alignment

00600

An alignment exception is caused when the 603 cannot perform a memory access for any of

several reasons, such as when the operand of a floating-point load or store operation is in an

I/O segment (SR[T] = 1).

Freescale Semiconductor, Inc.

For More Information On This Product,

Go to: www.freescale.com

AR

CH

IVE

D B

Y F

RE

ES

CA

LE

SE

MI

CO

ND

UC

TO

R,

INC

.