CHAPTER 3 CPU
Preliminary User’s Manual A14874EJ3V0UM
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3.2 Registers
The CPU registers can be classified into program registers, which are used by programs, and system registers,
which are used to control the execution environment. All registers are 32-bit registers.
Figure 3-1. List of CPU Registers
(a) Program registers
r0 (Zero register)
r1 (Assembler-reserved register)
r2
r3 (Stack pointer (SP))
r4 (Global pointer (GP))
r5 (Text pointer (TP))
r6
r7
r8
r9
r10
r11
r12
r13
r14
r15
r16
r17
r18
r19
r20
r21
r22
r23
r24
r25
r26
r27
r28
r29
r30 (Element pointer (EP))
r31 (Link pointer (LP))
PC (Program counter)
0
31
(b) System registers
EIPC (Register for saving status when interrupt occurs)
EIPSW (Register for saving status when interrupt occurs)
FEPC (Register for saving status when NMI occurs)
FEPSW (Register for saving status when NMI occurs)
ECR (Interrupt source register)
PSW (Program status word)
CTPC (Register for saving status when CALLT is executed)
CTPSW (Register for saving status when CALLT is executed)
DBPC (Register for saving status when exception is trapped)
DBPSW (Register for saving status when exception is trapped)
CTBP (CALLT base pointer)
0
31