General-Purpose Register; Fig. 2.27 Allocation And Configuration Of General-Purpose Register Banks In Memory Space - Fujitsu MB90420/5 (A) Series Hardware Manual

MB90420/5 (A) SERIES F

2.8 General-purpose Register

The general-purpose register is a memory block allocated to RAM addresses 000180
banks units of 16 bits × 8. A register bank can be used as a general-purpose 8-bit register (byte registers R0
to R7), 16-bit register (word registers RW0 to RW7), or 32-bit register (long word registers RL0 to RL7).
A general-purpose register allocated to RAM can be accessed quickly with a short instruction. The general-
purpose register area is divided into register bank blocks, so it is easy to protect data and divide the general-
purpose register by the function.
Also, when used as a long word register, it can be used as a linear pointer that accesses the entire space
directly.
n Configuration of general-purpose register
There are 32 general-purpose register banks in total at RAM addresses 000180
bank pointer (RP) is used to specify the bank to be used. When the RP is read, the currently used bank is
indicated. The RP determines the starting address of each bank as the following expression.
Starting address of general-purpose register = 000180
Figure 2.27 shows the allocation and configuration of the general-purpose register banks in memory space.
Internal RAM
000380
H
Register bank 31
000370
H
Register bank 30
000360
H
0002E0
H
Register bank 21
0002D0
H
Register bank 20
0002C0
H
Register bank 19
0002B0
H
0001B0
H
Register bank 2
0001A0
H
Register bank 1
000190
H
Register bank 0
000180
H

Fig. 2.27 Allocation and Configuration of General-Purpose Register Banks in Memory Space

Note: The register bank pointer (RP) is initialized to 00
2
MC-16LX FAMILY 16-BIT MICROCONTROLLERS HARDWARE MANUAL
Byte address
•
•
•
•
•
•
•
•
•
14
RP
H
•
•
•
•
+ RP × 10
H H
Byte address
02CE R6 R7 02CF
H
02CC R4 R5 02CD
H
02CA R2 R3 02CB
H
02C8 R0 R1 02C9
H
02C6 02C7
RW3
H
02C4 02C5
RW2
H
02C2 02C3
RW1
H
02C0 02C1
RW0
H
LSB MSB
16 bits
Conversion expression [000180
R0 to R7 : Byte register
RW0 to RW7 : Word register
RL0 to RL3 : Long-word register
MSB : Most Significant Bit
LSB : Least Significant Bit
after a reset.
H
2-28
to 00037F in register
H H
to 00037F . The register
H H
RW7
H
RL3
RW6
H
RW5
H
RL2
RW4
H
H
RL1
H
H
RL0
H
+ RP × × 10
]
H H