CHAPTER 3 SYSTEM CONTROLLER
228 Preliminary User’s Manual S15543EJ1V0UM
However, when making half-word accesses into a data array consisting of word data, access to the more-significant half word requires the address corresponding to the less significant half word (and vice versa). Such codeis not endian-independent. A super-group access (for example, accessing two half words simultaneously as a wordfrom a half-word data array) causes the same problem. Such problems also arise when a half-word access is madeinto a 32-bit register, whereas a word access into a 32-bit register creates no problem.Figure 3-3. Word Data Array Example

Word

Data Array

Big-Endian

Data extraction using sequential halfword access

W1
W0
LSHWMSHW

Little-Endian

MSHW LSHW
A B C D
E F G H
I J K L
M N O P
A B C D
E F G H
I J K L
M N O P
Order Retained

Data extraction using sequential halfword access

A B C D E F G H
I J K L M N O P
Order Lost
A B C D E F G H
I J K L M N O P W1
W0 A B C D E F G H
I J K L M N O P
A B C D E F G H
I J K L M N O P