8051 Immediate Addressing Mode

Immediate Addressing Mode

• In this mode, the source operand is an 8-bit or 16-bit constant value
• Constant is specified in instruction rather than in a register or memory location
• Immediate operands are preceded by #
• Operands may be numeric constant, a symbolic variable, or an arithmetic expression using constants, symbols and operators
• Assembler computes the value and substitutes the immediate data into the instruction
• The value to be stored in memory immediately follows the operation code in memory
• Example:
ADD A, #30H
The above instruction add constant 30H to value in accumulator
MOV DPTR, #FE00H
The above instruction move constant FE00H to DPTR

We can use directives to access immediate data as shown below.
COUNT        EQU    30
....
MOV R4, #COUNT    ; R4 = 30
MOV DPTR, #DATA   ; DPTR = 200H
....
ORG 200H
DATA:    DB    “HELLO”
....

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Related topics:
8051 Addressing Modes   |   8051 Register Addressing Mode   |   8051 Direct Addressing Mode   |   8051 Indirect Addressing Mode   |   8051 Relative Addressing Mode   |   8051 Absolute Addressing Mode   |   8051 Long Addressing Mode   |   8051 Indexed Addressing Mode   |   8051 External Addressing Mode

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List of topics: 8051

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