MB89560A Datasheet, PDF (21/60 Pages) Fujitsu Component Limited. – 8-bit Proprietary Microcontroller CMOS

MB89560A Series
2. Registers
The F²MC-8L family has two types of registers; dedicated registers in the CPU and general-purpose registers
in the memory. The following registers are provided:
Program counter (PC) : A 16-bit register for indicating specifies instruction storage positions.
Accumulator (A)
: A 16-bit temporary register for storing arithmetic operations, etc. When the
instruction is an 8-bit data processing instruction, the lower byte is used.
Temporary accumulator (T): A 16-bit register which performs arithmetic operations with the accumulator when
the instruction is an 8-bit data processing instruction, the lower byte is used.
Index register (IX)
: A 16-bit register for index modification
Extra pointer (EP)
: A 16-bit pointer for indicating a memory address
Stack pointer (SP)
: A 16-bit register for indicating a stack area
Program status (PS)
: A 16-bit register for storing a register pointer, a condition code
16 bits
PC
A
IX
EP
SP
PS
Initial value
: Program counter
FFFDH
: Accumulator
: Temporally accumulator
: Indexing register
: Extra pointer
Undefined
Undefined
Undefined
Undefined
: Stuck pointer
: Program status
Undefined
I Flag = 0, IL1, 0 = 11
other bits are undefined.
The PS can further be divided into higher 8 bits for use as a register bank pointer (RP) and the lower 8 bits for
use as a condition code register (CCR). (See the diagram below.)
• Structure of program status
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
PS
RP
Va- Va- Va-
cancy cancy cancy H I IL1 IL0 N Z V C
RP
CCR
21