S3F84B8_UM_REV 1.00 3 ADDRESSING MODES
3-3
3.3 INDIRECT REGISTER (IR) ADDRESSING MODE
In Indirect Register (IR) addressing mode, the content of a specified register or register pair is the address of
operand. Depending on the instruction used, the actual address can point to a register in register file, to program
memory (ROM), or to an external memory space (see Figure 3-3
through 3-6).
You can use any 8-bit register to indirectly address another register. Any 16-bit register pair can be used to
indirectly address another memory location. Note that you cannot access locations C0H–FFH in set 1 using the
Indirect Register addressing mode.
dst
Address of Operand
used by Instruction
OPCODE
ADDRESS
8-bit Register
File Address
Point to One
Register in Register
File
One-Operand
Instruction
(Example)
Sample Instruction:
RL @SHIFT ; Where SHIFT is the label of an 8-bit register address
Program Memory Register File
Value used in
Instruction Execution
OPERAND
Figure 3-3 Indirect Register Addressing to Register File
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