Assembly Language Questions Long
In Assembly Language, immediate addressing and direct addressing are two different ways to access data or operands in memory.
Immediate addressing refers to a method where the operand value is directly specified within the instruction itself. In other words, the data is immediately available to the instruction. The operand value is typically a constant or a literal value. This means that the instruction itself contains the actual data to be operated on, rather than referring to a memory location. Immediate addressing is useful when the operand value is known at compile-time or when performing simple arithmetic operations. For example, in the instruction "ADD R1, #5", the value 5 is directly specified in the instruction, and the content of register R1 is added to this immediate value.
On the other hand, direct addressing involves specifying the memory address where the operand is located. The instruction refers to a memory location to fetch or store the operand value. The memory address can be specified explicitly or indirectly through a register. Direct addressing is commonly used when the operand value is stored in memory and needs to be accessed or modified. For example, in the instruction "MOV R2, [R1]", the content of register R1 is treated as a memory address, and the value stored at that memory location is moved into register R2.
In summary, the main difference between immediate addressing and direct addressing in Assembly Language is that immediate addressing directly specifies the operand value within the instruction itself, while direct addressing refers to a memory location where the operand value is stored. Immediate addressing is useful for constants or literals, while direct addressing is used for accessing or modifying data stored in memory.