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# Arithmetic Micro-operations

In general, the Arithmetic Micro-operations deals with the operations performed on numeric data stored in the registers.

The basic Arithmetic Micro-operations are classified in the following categories:

- Addition
- Subtraction
- Increment
- Decrement
- Shift

Some additional Arithmetic Micro-operations are classified as:

- Add with carry
- Subtract with borrow
- Transfer/Load, etc.

The following table shows the symbolic representation of various Arithmetic Micro-operations.

Symbolic Representation | Description |
---|---|

R3 ← R1 + R2 | The contents of R1 plus R2 are transferred to R3. |

R3 ← R1 – R2 | The contents of R1 minus R2 are transferred to R3. |

R2 ← R2′ | Complement the contents of R2 (1’s complement) |

R2 ← R2′ + 1 | 2’s complement the contents of R2 (negate) |

R3 ← R1 + R2′ + 1 | R1 plus the 2’s complement of R2 (subtraction) |

R1 ← R1 + 1 | Increment the contents of R1 by one |

R1 ← R1 – 1 | Decrement the contents of R1 by one |

#### Note: The increment and decrement micro-operations are symbolized by ‘+ 1’ and ‘? 1’ respectively. Arithmetic operations like multiply and divide are not included in the basic set of micro-operations.

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