Indirect Address (Ia) Mode - Samsung S3F84B8 User Manual

S3F84B8_UM_REV 1.00

3.12 INDIRECT ADDRESS (IA) MODE

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 next instruction to be executed.
Only the CALL instruction can use the Indirect Address mode.
Since the assumption in using Indirect Address mode is 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 destination address are
assumed to be all zeros.
Sample Instruction:
CALL
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
Next Instruction
LSB Must be Zero
dst
Program Memory
Locations 0-255
Indirect Addressing
3-12
3 ADDRESSING MODES