Direct Page Addressing Mode Dp - Hyundai GMS800 Instruction Manual

HYUNDAI MicroElectonics
1.3. Direct Page Addressing Mode
The address field of the instruction gives the address of the operand in memory. The 2nd byte of instruction
is the offset from the start address of direct page. Direct Page(dp) is determined by G-flag.
G=0 0-Page ( !0000H ~ !00FFH)
OP CODE
Operand
A
X
Y
Memory
Example)
05 35
Example)
89 35
4


dp
ADC AND CMP
LDX CMPX
LDY CMPY
ASL COM DEC
( G=1 )
ADC 35H
( G=1 )
INC 35H
dp
G=1 1-Page ( !0100H ~ !01FFH)
Instructions
LDA EOR
INC LSR
A ← A+data+C
data ← data + 1
OR SBC
ROL ROR TST
MEMORY
000
h
0FF
h
100
h
data
135
h
1FF
h
Op code ( 05 )
Operand ( 35 )
MEMORY
000
h
0FF
h
100
h
data
135
h
1FF
h
Op code ( 89 )
Operand ( 35 )
0 Page 0 Page
1 Page
0 Page 0 Page
1 Page