HMS81008E Hynix Semiconductor, HMS81008E Datasheet - Page 20

• Manufacturer Part Number: HMS81008E
• Description: HYNIX SEMICONDUCTOR 8-BIT SINGLE-CHIP MICROCONTROLLERS
• Manufacturer: Hynix Semiconductor

used.
Program Counter:
The Program Counter is a 16-bit wide which consists of
two 8-bit registers, PCH and PCL. This counter indicates
the address of the next instruction to be executed. In reset
state, the program counter has reset routine address
(PC
Program Status Word:
The Program Status Word (PSW) contains several bits that
JUNE 2001 Ver 1.00
H
:0FF
15
SP before
execution
SP after
execution
H
, PC
01FC
01FD
01FE
01FF
At execution of
a CALL/TCALL/PCALL
Hardware fixed
Stack Address ( 100
L
:0FE
01
H
PCL
PCH
01FF
01FD
H
).
SP before
execution
SP after
execution
8
Push
down
7
H
01FC
01FD
01FE
01FF
~ 1FF
At execution
of PUSH instruction
PUSH A (X,Y,PSW)
SP
H
)
01FC
01FD
01FE
01FF
01FF
01FE
A
At acceptance
of interrupt
0
PSW
PCH
PCL
Figure 8-3 Stack Operation
01FF
01FC
Push
down
Push
down
01FC
01FD
01FE
01FF
At execution
of POP instruction
POP A (X,Y,PSW)
01FC
01FD
01FE
01FF
reflect the current state of the CPU. The PSW is described
in Figure 8-4 . It contains the Negative flag, the Overflow
flag, the Break flag the Half Carry (for BCD operation),
the Interrupt enable flag, the Zero flag, and the Carry flag.
[Carry flag C]
This flag stores any carry or borrow from the ALU of CPU
after an arithmetic operation and is also changed by the
Shift Instruction or Rotate Instruction.
Caution:
The Stack Pointer must be initialized by software be-
cause its value is undefined after RESET.
Example: To initialize the SP
01FE
01FF
A
At execution
of RET instruction
PCH
PCL
01FD
01FF
Pop
up
LDX
TXSP
Pop
up
HMS81004E/08E/16E/24E/32E
#0FFH
01FC
01FD
01FE
01FF
0100H
01FFH
At execution
of RETI instruction
PSW
PCH
PCL
01FC
01FF
; SP
Stack
depth
Pop
up
FF
H
17