The symbolic notation used to describe the micro operation transfers among register is called a register transfer language.

A register transfer language is a system for expressing in symbolic form the micro operation sequences among the register of a digital module.

## For example,

R1 ← R2

- This statement denotes a transfer of the content of register R2 into register R1.
- Here, content of R1 is replaced by content of R2.
- Content of R2 is not affected by this transfer.

If there is a condition, such that.

If (P = 1) then (R1 ← R2)

Where P is a control signal generated by the control bus.

Above statement can be used as,

P=1: R1 ← R2

The control condition ‘P=1’ is terminated with a colon. It symbolizes the requirement that the transfer operation be executed by the hardware only if P= 1.

## Basic symbols for Register Transfer Language

Symbol | Description | Examples |
---|---|---|

Letters & numerals | Denotes a register | MAR, R2 |

Parenthesis ( ) | Denotes a part of a register | R2(0-7), R2(L) |

Arrow ← | Denotes transfer of information | R2 ← R1 |

Comma , | Separates two micro operations | R2 ← R1, R1 ← R2 |

## For example,

T=1: R2 ← R1, R1 ← R2

- Registers (R1, R2) are denoted by capital letters, and numerals.
- Parentheses ( ) are used to denote a part of a register.
- The arrow (←) denotes a transfer of information and the direction of transfer.
- A comma ( , ) is used to separate two or more operations that are executed at the same time.

#### References:

- William stalling ,“Computer Architecture and Organization” PHI
- Morris Mano , “Computer System Organization ”PHI