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MB90335 Series
2.7
Register Bank
A register bank that consists of 8 words can be used as the general-purpose registers
for the arithmetic operations or as the pointers for the instructions, such as byte
registers (R0 to R7), word registers (RW0 to RW7), and long word registers (RL0 to RL3).
In addition, RL0 to RL3 can also be used as the linear pointers to access directly to the
entire space in the memory space.
■ Register Bank
Table 2.7-1 lists the register functions. Table 2.7-2 shows the relationship between each register.
In the same manner as for an ordinary RAM area, the register bank values are not initialized by a reset. The
status before a reset is maintained. When the power is turned-on, however, the register bank will have an
undefined value.
Table 2.7-1 Register Functions
Used as operands of instructions.
R0 to R7
Note:
Used as pointers and operands of instructions.
RW0 to RW7
Note:
RL0 to RL3
Used as long pointers and operands of instructions.
Table 2.7-2 Relationship between Registers
Address
+ RP × 10
000180
H
+ RP × 10
000180
H
+ RP × 10
000180
H
+ RP × 10
000180
H
+ RP × 10
000180
H
+ RP × 10
000180
H
+ RP × 10
000180
H
+ RP × 10
000180
H
+ RP × 10
000180
H
+ RP × 10
000180
H
+ RP × 10
000180
H
+ RP × 10
000180
H
+ RP × 10
000180
H
+ RP × 10
000180
H
+ RP × 10
000180
H
+ RP × 10
000180
H
CM44-10137-6E
R0 is also used as a counter for barrel shift or normalization instruction
RW0 is used as a counter for string instructions.
Byte register
+ 0
H
+ 1
H
+ 2
H
+ 3
H
+ 4
H
+ 5
H
+ 6
H
+ 7
H
+ 8
H
+ 9
H
+ 10
H
+ 11
H
+ 12
H
+ 13
H
+ 14
H
+ 15
H
FUJITSU MICROELECTRONICS LIMITED
Word register
RW7
RW6
RW5
RW4
R7
RW3
R6
R5
RW2
R4
R3
RW1
R2
R1
RW0
R0
CHAPTER 2 CPU
2.7 Register Bank
Long word register
RL3
RL2
RL1
RL0
39
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