Fujitsu F2MC-16LX Hardware Manual page 42

CHAPTER 2 CPU
I Allocation of data of multi-byte length in memory space
Figure 2.2-5 "Example of allocating data of multi-byte length in memory" shows the
configuration of data of a multi-byte length in memory. The lower 8 bits of a data item are
stored at address n, then address n+1, address n+2, address n+3, etc.
Figure 2.2-5 Example of allocating data of multi-byte length in memory
H
01010101
11001100
11111111
Address n
00000000
L
Data is written in memory in sequence starting from the lower addresses. Thus, the lower 16
bits of a 32-bit data item is transferred first, followed by the upper 16 bits. If a reset signal is
input immediately after writing the lower bit, writing the upper bit may fail.
I Access to data of multi-byte length
Figure 2.2-6 "Example of accessing data of multi-byte length" shows an example of accessing
data of a multi-byte length.
In this example, MOVW A, 030FFFF
Figure 2.2-6 Example of accessing data of multi-byte length
80FFFF
H
800000
H
26
H
01
H
·
·
·
23
H
L
MSB
01010101 1100110
is executed.
H
AL before execution
AL after execution
LSB
11111111 00000000
?? ??
23 01
H H