HD6433308 HITACHI [Hitachi Semiconductor], HD6433308 Datasheet - Page 42

• Manufacturer Part Number: HD6433308
• Description: Hitachi Single-Chip MicroComputer
• Manufacturer: HITACHI [Hitachi Semiconductor]

3.2 Register Configuration
Figure 3-1 shows the register structure of the CPU. There are two groups of registers: the general
registers and control registers.
3.2.1 General Registers
All the general registers can be used as both data registers and address registers. When used as
address registers, the general registers are accessed as 16-bit registers (R0 to R7). When used as
data registers, they can be accessed as 16-bit registers, or the high and low bytes can be accessed
separately as 8-bit registers.
R7 also functions as the stack pointer, used implicitly by hardware in processing interrupts and
subroutine calls. In assembly-language coding, R7 can also be denoted by the letters SP. As
indicated in figure 3-2, R7 (SP) points to the top of the stack.
15
7
R0H
R1H
R2H
R3H
R4H
R5H
R6H
R7H
CCR
PC
(SP)
0
7
7
Figure 3-1. CPU Registers
I
U
5
H
R0L
R1L
R2L
R3L
R4L
R5L
R6L
R7L
U
3
N
Z
2
1
V
0
C
0
26
0
SP: Stack Pointer
PC: Program Counter
CCR: Condition Code Register
Carry flag
Overflow flag
Zero flag
Negative flag
Half-carry flag
Interrupt mask bit
User bit
User bit