Quartus II Settings File Reference Manual - Altera

4–40 Chapter 4: Analysis & Synthesis Assignments
AUTO_SHIFT_REGISTER_RECOGNITION
AUTO_SHIFT_REGISTER_RECOGNITION
Type
Allows the Compiler to find a group of shift registers of the same length that can be
replaced with the altshift_taps megafunction. The shift registers must all use the same
clock and clock enable signals, must not have any other secondary signals, and must
have equally spaced taps that are at least three registers apart.
This option is useful for finding areas of the design that can be implemented more
efficiently, and as a result, minimizing the area and maximizing the speed of the
design.
This option can be used as a project-wide option, or assigned to a design entity.
This option is turned on by default.
Enumeration
■ Always
■ Auto
■ Off
Device Support
This setting can be used in projects targeting the following device families:
■ Arria GX
■ Arria II GX
■ Arria II GZ
■ Arria V
■ Cyclone
■ Cyclone II
■ Cyclone III
■ Cyclone III LS
■ Cyclone IV E
■ Cyclone IV GX
■ Cyclone V
■ HardCopy II
■ HardCopy III
■ HardCopy IV
■ MAX II
■ MAX V
■ Stratix
■ Stratix GX
Quartus Settings File June 2012 Altera Corporation
Reference Manual