Registers

R

Exception Status Register (ESR)

The Exception Status Register contains status bits for the processor. When read with the MFS instruction the ESR is specified by setting Sa = 0x0005.

19

20

26

27

31

 

 

 

 

RESERVED

 

DS

ESS

EC

 

 

Figure 1-6: ESR

 

 

Table 1-11:Exception Status Register (ESR)

 

 

 

 

 

 

 

 

Bits

Name

 

Description

 

Reset Value

 

 

 

 

 

 

0:18

Reserved

 

 

 

 

 

 

 

 

 

 

19

DS

 

Exception in delay slot.

 

0

 

 

 

0 not caused by delay slot instruction

 

 

 

 

1 caused by delay slot instruction

 

 

 

 

Read-only

 

 

 

 

 

 

 

 

20:26

ESS

 

Exception Specific Status

 

See Table 1-12

 

 

 

For details refer to Table 1-12.

 

 

 

 

 

Read-only

 

 

 

 

 

 

 

 

27:31

EC

 

Exception Cause

 

0

 

 

 

00001 = Unaligned data access exception

 

 

 

 

00010 = Illegal op-code exception

 

 

 

 

00011 = Instruction bus error exception

 

 

 

 

00100 = Data bus error exception

 

 

 

 

 

00101 = Divide by zero exception

 

 

 

 

00110 = Floating point unit exception

 

 

 

 

Read-only

 

 

 

 

 

 

 

 

MicroBlaze Processor Reference Guide

www.xilinx.com

25

UG081 (v6.0) June 1, 2006

1-800-255-7778

 

Page 25
Image 25
Xilinx EDK 8.2i manual Exception Status Register ESR, Ess