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CHAPTER 3 CPU ARCHITECTURE
Preliminary User’s Manual U16035EJ1V0UM
3.1.5 Data memory addressing
Addressing refers to the method of specifying the address of the instruction to be executed next or the address
of the register or memory relevant to the execution of instructions.
The address of an instruction to be executed next is addressed by the program counter (PC) (for details, see
3.3
Instruction Address Addressing
).
Several addressing modes are provided for addressing the memory relevant to the execution of instructions for
the
µ
PD780024AS, 780034AS Subseries, based on operability and other considerations. For areas containing data
memory in particular, special addressing methods designed for the functions of special function registers (SFR) and
general-purpose registers are available for use. Data memory addressing is illustrated in Figures 3-6 to 3-10. For
the details of each addressing mode, see
3.4 Operand Address Addressing
.
Figure 3-6. Data Memory Addressing (
µ
PD780021AS, 780031AS)
0000H
General-purpose registers
32
×
8 bits
Internal ROM
8192
×
8 bits
2000H
1FFFH
FEE0H
FEDFH
FF00H
FEFFH
FFFFH
Internal high-speed RAM
512
×
8 bits
Reserved
FD00H
FCFFH
FF20H
FF1FH
FE20H
FE1FH
Special function
registers (SFRs)
256
×
8 bits
SFR addressing
Register addressing
Short direct
addressing
Direct addressing
Register indirect
addressing
Based addressing
Based indexed
addressing