Little-endian, Data extraction using sequential halfword access – NEC Network Controller uPD98502 User Manual
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CHAPTER 3 SYSTEM CONTROLLER
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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 code
is not endian-independent. A super-group access (for example, accessing two half words simultaneously as a word
from a half-word data array) causes the same problem. Such problems also arise when a half-word access is made
into a 32-bit register, whereas a word access into a 32-bit register creates no problem.
Figure 3-3. Word Data Array Example
W o r d
D a t a A r r a y
Big-Endian
Data extraction using sequential halfword access
W 1
W 0
L S H W
M S H W
Little-Endian
M S H W
L S H W
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Order Retained
Data extraction using sequential halfword access
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Order Lost
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W 1
W 0
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