GMS81C2020 Datasheet, PDF (39/92 Pages) Hynix Semiconductor – CMOS Single-Chip 8-Bit Microcontroller with A/D Converter & VFD Driver

Hyundai Micro Electronics
GMS81C2020/GMS81C2120
11.5 Addressing Mode
The GMS87C1404 and GMS87C1408 uses six addressing
modes;
• Register addressing
• Immediate addressing
• Direct page addressing
• Absolute addressing
• Indexed addressing
• Register-indirect addressing
(1) Register Addressing
Register addressing accesses the A, X, Y, C and PSW.
(2) Immediate Addressing → #imm
In this mode, second byte (operand) is accessed as a data
immediately.
Example:
0435 ADC #35H
MEMORY
04
A+35H+C → A
35
(3) Direct Page Addressing → dp
In this mode, a address is specified within direct page.
Example;
C535 LDA 35H
;A ←RAM[35H]
0035_H
data
~~
0F550_H
C5
0F551_H
35
À
~~ _þ data → A
(4) Absolute Addressing → !abs
Absolute addressing sets corresponding memory data to
Data , i.e. second byte(Operand I) of command becomes
lower level address and third byte (Operand II) becomes
upper level address.
With 3 bytes command, it is possible to access to whole
memory area.
ADC, AND, CMP, CMPX, CMPY, EOR, LDA, LDX,
LDY, OR, SBC, STA, STX, STY
Example;
0735F0 ADC !0F035H
;A ←ROM[0F035H]
E45535 LDM 35H,#55H
0035_H
data
~~
þ
0F100_H
E4
0F101_H
55
0F102_H
35
data ← 55H
~~
À
0F035_H
data
~~
0F100_H
07
0F101_H
35
0F102_H
F0
~~
þ
À
A+data+C → A
address: 0F035
Nov. 1999 Ver 0.0
preliminary
39