Side-by-side reference

Understand the difference.

Compare the meaning, drawing context and source references of two entries. A similar graphic or shared abbreviation does not establish equivalence.

First referenceCompare with

CPG

IEC

IEC look-ahead carry generator (CPG)

The CPG qualifier identifies a look-ahead carry generator. It takes carry generate and carry propagate signals from several adder or ALU stages and produces their carry inputs in parallel, avoiding the delay of a rippling carry chain.

Drawing use: Schematic
Application: Logic & signals
Reference family: IEC / Manufacturer
Form evidence: Rectangular element with CPG qualifier. Qualifying-symbol and dependency conventions as explained in TI's public overview of IEEE Std 91-1984, which incorporates IEC 617-12 work. Independent educational drawing; not certified IEC geometry or an IEC database identifier.

A distinction that matters

A ripple-carry arrangement chains CO to CI directly with no CPG element.

Full reference

ALU

IEC

IEC arithmetic logic unit (ALU)

The ALU qualifier identifies an element that can perform several arithmetic and logic operations on input words P and Q. Function-select inputs use M dependency or a binary grouping to choose the operation, and outputs include the result, carry and often a P=Q flag. Because the function table is large, the symbol usually refers to a table on the drawing or in the datasheet.

Drawing use: Schematic
Application: Logic & signals
Reference family: IEC / Manufacturer
Form evidence: Rectangular element with ALU qualifier and mode-select inputs. Qualifying-symbol and dependency conventions as explained in TI's public overview of IEEE Std 91-1984, which incorporates IEC 617-12 work. Independent educational drawing; not certified IEC geometry or an IEC database identifier.

A distinction that matters

The Σ element only adds; the ALU selects among many operations, including subtraction and logic functions.

Full reference

Original educational previews. Follow the source references on each full entry for the appropriate standard or selected product.