R

Chapter 1: MicroBlaze Architecture

031

PC

Figure 1-3: PC

Table 1-8:Program Counter (PC)

Bits

Name

Description

Reset Value

 

 

 

 

0:31

PC

Program Counter

0x00000000

 

 

Address of executing instruction,

 

 

 

i.e. “mfs r2 0” will store the address

 

 

 

of the mfs instruction itself in R2

 

 

 

 

 

Machine Status Register (MSR)

0

CC

The Machine Status Register contains control and status bits for the processor. It can be read with an MFS instruction. When reading the MSR, bit 29 is replicated in bit 0 as the carry copy. MSR can be written using either an MTS instruction or the dedicated MSRSET and MSRCLR instructions.

When writing to the MSR, some of the bits will takes effect immediately (e.g Carry) and the remaining bits take effect one clock cycle later. Any value written to bit 0 is discarded. When used with an MTS or MFS instruction the MSR is specified by setting Sx = 0x0001.

 

 

 

 

 

 

21

22

 

 

23

 

24

 

25

 

26

 

27

 

 

28

29

 

30

31

 

 

 

 

 

 

 

 

 

 

↑ ↑

 

 

 

 

↑ ↑

 

 

 

 

 

 

 

 

 

↑ ↑

 

 

 

 

 

 

 

 

 

 

 

 

RESERVED

 

 

PVR EIP EE DCE DZ ICE FSL BIP

C

IE

BE

 

 

 

 

Figure 1-4: MSR

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Table 1-9:Machine Status Register (MSR)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Bits

 

Name

 

Description

 

 

 

 

 

 

 

 

Reset Value

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

0

 

CC

 

Arithmetic Carry Copy

 

 

 

 

 

 

 

 

0

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Copy of the Arithmetic Carry (bit 29).

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

CC is always the same as bit C.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

1:20

 

Reserved

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

21

 

PVR

 

Processor Version Register exists

 

 

 

 

Based on

 

 

 

 

 

 

 

 

 

 

0 No Processor Version Register

 

 

 

 

 

option

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

C_PVR

 

 

 

 

 

 

 

 

 

 

1 Processor Version Register exists

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Read only

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

22

www.xilinx.com

MicroBlaze Processor Reference Guide

 

1-800-255-7778

UG081 (v6.0) June 1, 2006

Page 22
Image 22
Xilinx EDK 8.2i manual Machine Status Register MSR, 8Program Counter PC Bits Name Description Reset Value, Pvr, Cpvr