R01UH0823EJ0100 Rev.1.00
Page 71 of 1823
Jul 31, 2019
RX23W Group
2. CPU
2.2.1
General-Purpose Registers (R0 to R15)
This CPU has sixteen 32-bit general-purpose registers (R0 to R15). R0 to R15 can be used as data registers or address
registers.
R0, a general-purpose register, also functions as the stack pointer (SP).
The stack pointer is switched to operate as the interrupt stack pointer (ISP) or user stack pointer (USP) by the value of the
stack pointer select bit (U) in the processor status word (PSW).
2.2.2
Control Registers
This CPU has the following ten control registers.
Interrupt stack pointer (ISP)
User stack pointer (USP)
Exception table register (EXTB)
Interrupt table register (INTB)
Program counter (PC)
Processor status word (PSW)
Backup PC (BPC)
Backup PSW (BPSW)
Fast interrupt vector register (FINTV)
Floating-point status word (FPSW)