Register (R) Addressing Mode - Samsung S3F84B8 User Manual

S3F84B8_UM_REV 1.00

3.2 REGISTER (R) ADDRESSING MODE

In Register (R) addressing mode, the operand value is the content of a specified register or register pair (see
Figure 3-1).
Working register addressing differs from Register addressing since it uses a register pointer to specify an 8-byte
working register space in the register file and an 8-bit register within that space (see
8-bit Register
File Address
One-Operand
Sample Instruction:
DEC
4-bit
Working Register
Two-Operand
Instruction
(Example)
Sample Instruction:
ADD
Program Memory
OPCODE
Instruction
(Example)
CNTR
Figure 3-1
Program Memory
dst src
OPCODE
R1, R2
Figure 3-2
dst
Point to One
Register in Register
File
Instruction Execution
; Where CNTR is the label of an 8-bit register address
Register Addressing
MSB Point to
RP0 ot RP1
3 LSBs
Point to the
Working Register
(1 of 8)
; Where R1 and R2 are registers in the currently
selected working register area.
Working Register Addressing
3-2
3 ADDRESSING MODES
Figure
Register File
OPERAND
Value used in
Register File
RP0 or RP1
OPERAND
3-2).
Selected
RP points
to start
of working
register
block