16 bit Assembly
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OR - OR Bitwise Instruction
The OR Instruction performs an OR action with the second operand on the first operand.
The first operand holds the result of this operation. All matching bits of 0 are retained, all other non-matching bits and 1's become 1.
This command has 3 parts, Instruction, then either operand can be a Register or Immediate value or a memory address.
However 2 memmory addresses cannot be used together.
| Assembly Sample | Description | 16 bit Machine Code |
|---|---|---|
| OR AL, 0x03 | ; 8 bit immediate number with AL | 0C 03 |
| OR AX, 0x0003 | ; 16 bit immediate number with AX | 0D 03 00 |
| OR BL, 0x03 | ; 8 bit immediate number with Register | 80 C3 03 |
| OR BX, 0x0003 | ; 16 bit immediate number with Register | 81 CB 03 00 |
| OR [BX], 0x03 | ; 8 bit immediate number with memory address | 80 0F 03 |
| OR [BX], 0x0003 | ; 16 bit immediate number with memory address | 81 0F 03 00 |
| OR AL, BL | ; 8 bit Registers | 08 D8 |
| OR BL, AL | ; 8 bit Registers | 0A D8 |
| OR AX, BX | ; 16 bit Registers | 09 D8 |
| OR BX, AX | ; 16 bit Registers | 0B D8 |
| OR [BX], AX | ; Register to memory address | 09 07 |
| OR AX, [BX] | ; Memory address to Register | 0B 07 |
| OR [BX+2], AX | ; Register to | 09 47 02 |
| OR AX, [BX+2] | ; Memory address and offset to Register | 0B 47 02 |
Last Update 06/02/2023