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ADDRESSING MODES
DIRECT ADDRESS MODE (DA)
In Direct Address (DA) mode, the instruction provides the operand's 16-bit memory address. Jump (JP) and Call
(CALL) instructions use this addressing mode to specify the 16-bit destination address that is loaded into the PC
whenever a JP or CALL instruction is executed.
The LDC and LDE instructions can use Direct Address mode to specify the source or destination address for
Load operations to program memory (LDC) or to external data memory (LDE), if implemented.
3-10
Program or
Data Memory
Program Memory
Upper Address Byte
Lower Address Byte
dst/src
OPCODE
Sample Instructions:
LDC
R5,1234H
LDE
R5,1234H
Figure 3-10. Direct Addressing for Load Instructions
S3C8275X/F8275X/C8278X/F8278X/C8274X/F8274X
Memory
Address
Used
"0" or "1"
LSB Selects Program
Memory or Data Memory:
"0" = Program Memory
"1" = Data Memory
;
The values in the program address (1234H)
are loaded into register R5.
;
Identical operation to LDC example, except that
external program memory is accessed.
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