Data Memory Addressing - NEC 78K0 User Manual

3.1.4 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.
Several addressing modes are provided for addressing the memory relevant to the execution of instructions for the
78K0/KC1, 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. Figures 3-6 to 3-10 show correspondence between data memory and addressing. For the details of
each addressing mode, see 3.4 Operand Address Addressing.
Figure 3-6. Correspondence Between Data Memory and Addressing (
FFFFH
Special function
registers (SFRs)
FF20H
FF1FH
FF00H
FEFFH
General-purpose registers
32 × 8 bits
FEE0H
FEDFH
Internal high-speed RAM
512 × 8 bits
FE20H
FE1FH
FD00H
FCFFH
2000H
1FFFH
Internal ROM
8192 × 8 bits
0000H
CHAPTER 3 CPU ARCHITECTURE
SFR addressing
256 × 8 bits
Register addressing
Reserved
User's Manual U16227EJ2V0UD
µ
PD780111)
Short direct
addressing
Direct addressing
Register indirect
addressing
Based addressing
Based indexed
addressing
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