Hyundai Micro Electronics
GMS81C2020/GMS81C2120
3F35
JMP
[35H]
Y indexed direct page (8 bit offset) → dp+Y
This address value is the second byte (Operand) of com-
mand plus the data of Y-register, which assigns Memory in
Direct page.
35
36
0A
E3
H
This is same with above (2). Use Y register instead of X.
H
À jump to address 0E30A
H
Y indexed absolute → !abs+Y
~
~
~
~
Sets the value of 16-bit absolute address plus Y-register
data as Memory. This addressing mode can specify mem-
ory in whole area.
0E30A
NEXT
H
H
~
~
~
~
þ
Example; Y=55H
0FA00
3F
35
D500FA LDA
!0FA00H+Y
0F100
H
D5
þ
0F101
0F102
00
H
H
X indexed indirect → [dp+X]
FA
0FA00H+55H=0FA55H
Processes memory data as Data, assigned by 16-bit pair
memory which is determined by pair data
[dp+X+1][dp+X] Operand plusꢁX-register data in Direct
page.
~
~
~
~
À
data
0FA55
H
data → A
Ã
ADC, AND, CMP, EOR, LDA, OR, SBC, STA
Example; X=10H
1625
ADC
[25H+X]
(6) Indirect Addressing
Direct page indirect → [dp]
35
36
05
H
E0
Assigns data address to use for accomplishing command
which sets memory data(or pair memory) by Operand.
Also index can be used with Index register X,Y.
H
0E005
H
À
~
~
~
~
25 + X(10) = 35
þ
H
0E005
data
H
H
JMP, CALL
Example;
~
~
~
~
0FA00
16
25
à A + data + C → A
Nov. 1999 Ver 0.0
preliminary
41
HYNIX [ HYNIX SEMICONDUCTOR ]
