Special-Function Register (Sfr) Addressing - NEC mPD780973 Series Preliminary User's Manual

3.4.5 Special-function register (SFR) addressing

[Function]
The memory-mapped special-function register (SFR) is addressed with 8-bit immediate data in an instruction
word.
This addressing is applied to the 240-byte spaces FF00H to FFCFH and FFE0H to FFFFH. However, the SFR
mapped at FF00H to FF1FH can be accessed with short direct addressing.
[Operand format]
Identifier
sfr
sfrp
[Description example]
MOV PM0, A; when selecting PM0 (FF20H) as sfr
[Operation]
7
15
Effective Address 1 1 1
62
CHAPTER 3 CPU ARCHITECTURE
Special-function register name
16-bit manipulatable special-function register name (even address only)
Operation code
0
OP code
sfr-offset
8 7
1 1 1 1 1
Description
1 1 1 1 0 1 1 0 OP code
0 0 1 0 0 0 0 0 20H (sfr-offset)
0
SFR