Fujitsu F2MC-8L Series Hardware Manual page 60

of the accumulator after a reset is indeterminate.
Temporary accumulator (T)
The temporary accumulator is an auxiliary 16-bit arithmetic operation register used to perform
arithmetic operations with the data in the accumulator (A). The content of the temporary
accumulator is treated as word data (16-bit) for word-length arithmetic operations with the
accumulator and as byte data (8-bit) for byte-length arithmetic operations. For byte-length
arithmetic operations, only the lower 8 bits of the temporary accumulator (TL) are used and the
upper 8 bits (TH) are not used.
Executing a transfer instruction to transfer data to the accumulator (A) automatically transfer the
previous content of the accumulator to the temporary accumulator. In this case also, a byte
transfer leaves the upper 8 bits of the temporary accumulator (TH) unchanged. The initial value
of the temporary accumulator after a reset is indeterminate.
Index register (IX)
The index register is a 16-bit register used to hold the index address. The index register is used
in conjunction with a single byte offset value (-128 to +127). Adding the sign-extended offset
value to the index address generates the memory address for data access. The initial value of
the index register after a reset is indeterminate.
Extra pointer (EP)
The extra pointer is a 16-bit register used to hold a memory address for data access. The initial
value of the extra pointer after a reset is indeterminate.
Stack pointer (SP)
The stack pointer is a 16-bit register used to hold the address referenced during operations
such as interrupts, subroutine calls, and the stack save and restore instructions. The value of
the stack pointer during program execution is the address of the most recently saved data on
the stack. The initial value of the stack pointer after a reset is indeterminate.
Program status (PS)
The program status is a 16-bit control register. The upper 8 bits contain the register bank pointer
(RP) which points to the address of the current general-purpose register bank.
The lower 8 bits contain the condition code register (CCR) which contains flags indicating the
current CPU status. The two 8-bit registers which form the program status cannot be accessed
independently (the program status can only be accessed by the MOVW A,PS and MOVW PS,A
instructions).
Reference:
2
Refer to the "F MC-8L MB89600" series Programming Manual for details on using the
dedicated registers.
3.2 Dedicated Registers
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