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ADDRESSING MODES S3F80JB
3-12
INDIRECT ADDRESS MODE (IA)
In Indirect Address (IA) mode, the instruction specifies an address located in the lowest 256 bytes of the program
memory. The selected pair of memory locations contains the actual address of the next instruction to be executed.
Only the CALL instruction can use the Indirect Address mode.
Because the Indirect Address mode assumes that the operand is located in the lowest 256 bytes of program
memory, only an 8-bit address is supplied in the instruction; the upper bytes of the destination address are
assumed to be all zeros.
Current
Instruction
Program Memory
Locations 0-255
Program Memory
OPCODE
dst
Lower Address Byte
Upper Address Byte
Next Instruction
LSB Must be Zero
Sample Instruction:
CALL #40H ; The 16-bit value in program memory addresses 40H
and 41H is the subroutine start address.
Figure 3-12. Indirect Addressing