mpc823rg Freescale Semiconductor, Inc, mpc823rg Datasheet - Page 354

• Manufacturer Part Number: mpc823rg
• Description: Mpc823 Powerquicc Integrated Communications Processor For Portable Systems
• Manufacturer: Freescale Semiconductor, Inc

14.1 LITTLE-ENDIAN FEATURES
The following is a list of the little-endian system’s main features:
The following tables describe how to handle the little-endian program or data in the
little-endian system that is built around the MPC823 for various port sizes.
• System Memory Organization and E-Bus Format are Little-Endian
• U-Bus Data, Instruction and Data Caches, and Internal Memory Format are Big-Endian
• Data Access Constraints that Follow the PowerPC Little-Endian Rules
• Same Byte Order between the Media and System Memory
• For Core Accesses, Swap and Address Demunging are Performed by the System
• The Core’s Load/Store Unit Swapper Uses Munged Addresses to Put the Data on the
• The Communication Processor Module Performs Data Swapping According to
Half-word
Half-word
FETCH/
STORE
LOAD
TYPE
Word
Byte
Byte
Byte
Byte
Interface Unit on the U-Bus to the System Path
Right Byte Lanes when Half-Word or Byte Accesses are Performed
Information in the Buffer Descriptors
ADDRESS
ENDIAN
LITTLE-
0
0
2
0
1
2
3
Table 14-3. Little-Endian Program/Data Path Between the
ADDRESS
CACHES
U-BUS
AND
0
2
0
3
2
1
0
Freescale Semiconductor, Inc.
For More Information On This Product,
EXTERNAL
ADDRESS
BUS
Register and 32-Bit Memory
0
0
2
0
1
2
3
MPC823 REFERENCE MANUAL
Go to: www.freescale.com
11
0
DATA IN THE
REGISTER
12
1
13
21
31
2
14
22
32
‘a’
‘b’
‘d’
‘c’
3
CACHES FORMAT
11
31
‘d’
0
U-BUS AND
12
32
‘c’
1
13
21
‘b’
2
14
22
‘a’
3
14
22
‘a’
0
E-BUS FORMAT
13
21
‘b’
1
12
32
‘c’
2
11
31
‘d’
3
Endian Modes
11
31
‘d’
PROGRAM/DATA
3
LITTLE-ENDIAN
12
32
‘c’
2
13
21
‘b’
1
14-3
14
22
‘a’
0