HMS87C1808B Datasheet, PDF (36/99 Pages) List of Unclassifed Manufacturers – 8-BIT SINGLE-CHIP MICROCONTROLLERS

HMS87C1X04B/08B/16B
8.4 Addressing Mode
The HMS87C1X04B/08B/16B 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 imme-
diately.
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
2
~~ ₁ 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 ad-
dress 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
~~
1
0F100_H
E4
0F101_H
55
0F102_H
35
data ← 55H
~~
2
0F035_H
~~
0F100_H
0F101_H
0F102_H
data
07
35
F0
~~
1
2
A+data+C → A
address: 0F035
32
SEP. 2004 Ver 1.03