Renesas M16C/29 Series Hardware Manual page 34

M16C/29 Group
2. Central Processing Unit (CPU)
Figure 2.1 shows the CPU registers. The CPU has 13 registers. Of these, R0, R1, R2, R3, A0, A1 and FB
comprise a register bank. There are two register banks.
b31
Figure 2.1. Central Processing Unit Register
2.1 Data Registers (R0, R1, R2 and R3)
The R0 register consists of 16 bits, and is used mainly for transfers and arithmetic/logic operations. R1 to
R3 are the same as R0.
The R0 register can be separated between high (R0H) and low (R0L) for use as two 8-bit data registers.
R1H and R1L are the same as R0H and R0L. Conversely, R2 and R0 can be combined for use as a 32-
bit data register (R2R0). R3R1 is the same as R2R0.
2.2 Address Registers (A0 and A1)
The register A0 consists of 16 bits, and is used for address register indirect addressing and address
register relative addressing. They also are used for transfers and arithmetic/logic operations. A1 is the
same as A0.
In some instructions, registers A1 and A0 can be combined for use as a 32-bit address register (A1A0).
Rev.1.00 Nov 01,2004
REJ09B0101-0100Z
b15
R2
R0H(R0's high bits)
R3
R1H(R1's high bits)R1L(R1's low bits)
b19
b15
INTBH
The upper 4 bits of INTB are INTBH and
the lower 16 bits of INTB are INTBL.
b19
b15
b15
b15
IPL
Note: These registers comprise a register bank. There are two register banks.
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b8 b7 b0
R0L(R0's low bits)
R2
R3
A0
A1
FB
b0
INTBL
b0
PC
b0
USP
ISP
SB
b0
FLG
b8 b7 b0
U I O B S Z D C
2. Central Processing Unit(CPU)
Data registers (Note)
Address registers (Note)
Frame base registers (Note)
Interrupt table register
Program counter
User stack pointer
Interrupt stack pointer
Static base register
Flag register
Carry flag
Debug flag
Zero flag
Sign flag
Register bank select flag
Overflow flag
Interrupt enable flag
Stack pointer select flag
Reserved area
Processor interrupt priority level
Reserved area