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ADDRESSING MODES
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.
Sample Instruction:
CALL
3-12
Program Memory
Current
OPCODE
Instruction
Lower Address Byte
Upper Address Byte
#40H
; The 16-bit value in program memory addresses 40H
and 41H is the subroutine start address.
Figure 3-12. Indirect Addressing
S3C8248/C8245/P8245/C8247/C8249/P8249
Next Instruction
LSB Must be Zero
dst
Program Memory
Locations 0-255
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