Fujitsu FR60 Hardware Manual page 80

CHAPTER 3 CPU AND CONTROL UNITS
■ RP (Return Pointer)
The configuration of the return pointer (RP) register is shown below:
The return pointer holds the address returned from a subroutine.
When a CALL instruction is executed, the PC value is transferred to this RP.
When a RET instruction is executed, the RP contents are transferred to PC.
The initial value after reset is undefined.
■ SSP (System Stack Pointer)
The configuration of the system stack pointer (SSP) register is shown below:
SSP is the system stack pointer.
SSP functions as R15 when the S flag is "0".
SSP can also be specified explicitly.
This register is also used as a stack pointer that specifies the stack on which the PS and PC contents are to
be saved if an EIT occurs.
The initial value after reset is 00000000
■ USP (User Stack Pointer)
The configuration of the user stack pointer (USP) register is shown below:
USP is the user stack pointer
USP functions as R15 when the S flag is "1".
USP can also be specified explicitly.
The initial value after reset is undefined.
This register cannot be used by the RETI instruction.
62
31
RP
31
SSP
H
31
USP
0 [Initial value]
XXXXXXXX
0 [Initial value]
00000000
.
0 [Initial value]
XXXXXXXX
H
H
H