
GMS81508/16
7
2. FUNCTIONS
2.1. REGISTERS
6 registers are built-in the CPU of G8MC. Accumulator(A), Index register X, Y, Stack Pointer (SP)
and Program Status Word(PSW) consists of 8-bit registers. Program Counter(PC) consists of 16-
bit registers. The contents of these registers are undefined after RESET.
Program Counter
15 8
PCH
7 0
PCL
A - Register
7 0
A
15 8
Y
( YA 16bit Accumulator )
7 0
A
X - Register
7 0
X
Y - Register
7 0
Y
Program Status Word
7 0
PSW
Stack Pointer
7 0
SP
Carry Flag
Z
C
H
I
G
B
N
V
Zero Flag
Interrupt Enable Flag
Half Carry Flag
Break Flag
G ( Direct Page ) Flag
Overflow Flag
Negative Flag