Table 2.1.2B Register Functions; Table 2.1.2C Relationship Between Registers - Fujitsu F2MC-16LX MB90580 Series Hardware Manual

2.1 CPU
Register bank
A register bank consists of eight words. The register bank can be used as the following general-purpose
registers for arithmetic operations: byte registers R0 to R7, word registers RW0 to RW7, and long word
registers RL0 to RL3. In addition, the register bank can be used as instruction pointers.
Table 2.1.2b lists the functions of the registers. Table 2.1.2c indicates the relationship between the
registers.
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.
R0 to R7
RW0 to RW7
RL0 to RL3
26 Chapter 2: CPU

Table 2.1.2b Register functions

Used as operands of instructions.
Note: R0 is also used as a counter for barrel shift or normalization instructions.
Used as pointers.
Used as operands of instructions.
Note: RW0 is used as a counter for string instructions.
Used as long pointers.
Used as operands of instructions.

Table 2.1.2c Relationship between registers

R0
R1
R2
R3
R4
R5
R6
R7
RW0
RL0
RW1
RW2
RL1
RW3
RW4
RL2
RW5
RW6
RL3
RW7
MB90580 Series