RX610 Group
2. CPU
R01UH0032EJ0120 Rev.1.20
Page 57 of 1006
Feb 20, 2013
2.2.2.1
Interrupt Stack Pointer (ISP)/User Stack Pointer (USP)
b31
ISP
b31
USP
Value after reset:
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Value after reset:
b0
b0
The stack pointer (SP) can be either of two types, the interrupt stack pointer (ISP) or the user stack pointer (USP).
Whether the stack pointer operates as the ISP or USP depends on the value of the stack pointer select bit (U) in the
processor status word (PSW).
Set the ISP or USP to a multiple of four, as this reduces the numbers of cycles required to execute interrupt sequences
and instructions entailing stack manipulation.
2.2.2.2
Interrupt Table Register (INTB)
b31
b0
Value after reset: Undefined
The interrupt table register (INTB) specifies the address where the relocatable vector table starts.
2.2.2.3
Program Counter (PC)
b31
Value after reset: Value allocated to addresses in the range from FFFFFFFCh to FFFFFFFFh
b0
The program counter (PC) indicates the address of the instruction being executed.