m38039mf-xxxsp Mitsumi Electronics, Corp., m38039mf-xxxsp Datasheet - Page 11

• Manufacturer Part Number: m38039mf-xxxsp
• Description: Single-chip 8-bit Cmos Microcomputer
• Manufacturer: Mitsumi Electronics, Corp.

Fig.9 740 Family CPU register structure
FUNCTIONAL DESCRIPTION
CENTRAL PROCESSING UNIT (CPU)
The 3803/3804 group uses the standard 740 Family instruction
set. Refer to the table of 740 Family addressing modes and ma-
chine instructions or the 740 Family Software Manual for details
on the instruction set.
Machine-resident 740 Family instructions are as follows:
[Accumulator (A)]
The accumulator is an 8-bit register. Data operations such as data
transfer, etc., are executed mainly through the accumulator.
[Index Register X (X)]
The index register X is an 8-bit register. In the index addressing
modes, the value of the OPERAND is added to the contents of
register X and specifies the real address.
[Index Register Y (Y)]
The index register Y is an 8-bit register. In partial instruction, the
value of the OPERAND is added to the contents of register Y and
specifies the real address.
The FST and SLW instructions cannot be used.
The STP, WIT, MUL, and DIV instructions can be used.
b15
PC
H
b7
b7
b7
b7
b7
b7
N V T B D I Z C
PC
A
X
Y
S
L
b0
b0
b0
b0
b0
b0
[Stack Pointer (S)]
The stack pointer is an 8-bit register used during subroutine calls
and interrupts. This register indicates start address of stored area
(stack) for storing registers during subroutine calls and interrupts.
The low-order 8 bits of the stack address are determined by the
contents of the stack pointer. The high-order 8 bits of the stack ad-
dress are determined by the stack page selection bit. If the stack
page selection bit is “0” , the high-order 8 bits becomes “00
the stack page selection bit is “1”, the high-order 8 bits becomes
“01
The operations of pushing register contents onto the stack and
popping them from the stack are shown in Figure 10.
Store registers other than those described in Figure 10 with pro-
gram when the user needs them during interrupts or subroutine
calls.
[Program Counter (PC)]
The program counter is a 16-bit counter consisting of two 8-bit
registers PC
next instruction to be executed.
16
”.
Accumulator
Index register X
Index register Y
Stack pointer
Program counter
Processor status register (PS)
Carry flag
Zero flag
Interrupt disable flag
Decimal mode flag
Break flag
Index X mode flag
Overflow flag
Negative flag
SINGLE-CHIP 8-BIT CMOS MICROCOMPUTER
H
and PC
MITSUBISHI MICROCOMPUTERS
L
. It is used to indicate the address of the
3803/3804 Group
16
”. If
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