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RL78/G1A CHAPTER 3 CPU ARCHITECTURE
R01UH0305EJ0200 Rev.2.00 83
Jul 04, 2013
3.4.3 Direct addressing
[Function]
Direct addressing uses immediate data in the instruction word as an operand address to directly specify the target
address.
[Operand format]
Identifier Description
!addr16 Label or 16-bit immediate data (only the space from F0000H to FFFFFH is specifiable)
ES:!addr16 Label or 16-bit immediate data (higher 4-bit addresses are specified by the ES register)
Figure 3-20. Example of !addr16
F0000H
A 16-bit address <1> in the 64 KB area from
F0000H to FFFFFH specifies the target location
(for use in access to the 2nd SFRs etc.).
MOV !addr16,
A
Instruction code
Target memory
Memory
<1>
<1>
OP-code
Low Addr.
High Addr.
FFFFFH
Figure 3-21. Example of ES:!addr16
00000H
X0000H
OP-code
Low Addr
.
High Addr
.
ES
The ES register <1> specifies a 64 KB area within the
overall 1-Mbyte space as the four higher-order bits, X, of
the address range.
A 16-bit address <2> in the area from X0000H to XFFFFH
and the ES register <1> specify the target location;
this is used for access to fixed data other than
that in mirrored areas.
Area from
X0000H to
XFFFFH
ES: !addr16
Specifies a
64 KB area
Specifies the
address in memory
Instruction code
Target memory
Memory
<1> <2>
<2>
FFFFFH