Prerequisite: Addressing Modes
1. Direct Addressing Mode:
In direct addressing mode, address field in the instruction contains the effective address of the operand and no intermediate memory access is required. Now a days it is rarely used.
Add the content of R1 and 1001 and store back to R1:
Add R1, (1001)
Here 1001 is the address where operand is stored.
2. Indirect Addressing Mode:
In Indirect addressing mode, address field in the instruction contains the memory location or register where effective address of operand is present. It requires two memory access. It is further classified into two categories: Register Indirect, and Memory Indirect.
LOAD R1, @500
Above instruction is used to load the content of memory location stored at memory location 500 to register R1. In other words we can say, effective address is stored at memory location 500.
Difference between Direct and Indirect Addressing Modes:
|S.NO||Direct Addressing Mode||Indirect Addressing Mode|
|1.||Address fields contains the effective address of operand||Address field contains reference of effective address|
|2.||Requires only one memory reference||Requires two memory refrences|
|3.||Fast addressing||Slower than direct addressing mode|
|4.||No further classification||Further classified into two categories|
|5.||No further calculation is required to perform the operation||Require further calculation to find the effective address|
- Difference between Memory based and Register based Addressing Modes
- Removing Direct and Indirect Left Recursion in a Grammar
- Addressing Modes
- Addressing modes in 8086 microprocessor
- Addressing modes in 8085 microprocessor
- 8085 program to swap two 16 bit numbers using Direct addressing mode
- 8085 program to swap two 8 bit numbers using Direct addressing mode
- 8255 microprocessor operating modes
- Direct memory access with DMA controller 8257/8237
- Classful Vs Classless Addressing
- Difference between RAM and ROM
- Difference between LAN, MAN and WAN
- Difference between CPU and GPU
- Difference between ARP and RARP
- Difference between MD5 and SHA1
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