Instruction Format

•Cond (4 bits):This field specifies the condition for the execution of the instruction

•Opcode (2 bits):This specifies the type of instruction.

•I (1 bit):Immediate flag .1 for immediate value usage and 0 for register usage

•P (1 bit):Pre/Post index flag. 1 for pre indexing and 0 for post indexing

•U (1 bit):Up/Down flag for address offset.1 means offset is added to base and 0 means offset is subtracted from base

•B (1 bit):Byte/Word flag. 1 indicates byte operation and 0 indicates word operation

•W (1 bit):Write-back flag. 1 means base register updated with new addr after operation and 0 means no updating

•L (1 bit):Load/Store flag. 1 means LDR and 0 means STR

•Rn (4 bits): This specifies the base register.

•Offset (12 bits): This specifies the offset value or address for memory access.         

1. Condition (Cond): Determines if the instruction should execute, based on specific conditions (e.g., flags in the status register).

2. Opcode: Specifies the operation (e.g., addition, subtraction, etc.) to be performed.

3. Rn, Rd, Rs, Rm: Registers used in the operation (source, destination, or others).

4. Immediate/Offset: Provides additional values or memory offsets.

5. Control Bits (e.g., P, U, W, L): Modify how the instruction works (e.g., pre/post-indexing for memory, direction of operations).

6. Types of Instructions: Listed on the right (e.g., Data Processing, Branch, Load/Store, etc.), showing the primary purpose of each format.