The option you are looking for is AUTO_IMPLEMENT_IN_ROM. It is available only for certain Device families. The details from the Quartus II online help are: A logic option that allows the Compiler to automatically implement combinational logic in ROM (that is, in an embedded cell within an Embedded System Block (ESB) or Embedded Array Block (EAB) that is set to use ROM mode), to improve speed or area usage. Using ROM in this way can free up logic cells that would otherwise be needed to implement the combinational logic.
This option is ignored if it is assigned to anything other than a design entity. The Auto Implement in ROM option is also ignored if you select Product Term as the setting for the Technology Mapper option. This option can be set in the Assignment Editor (Assignments menu) or the Analysis & Synthesis Settings page or the Fitter Settings page of the Settings dialog box (Assignments menu). This option is available for ACEX® 1K, APEXT 20K, APEX 20KC, APEX 20KE, APEX II, ARM®-based ExcaliburT, FLEX 10K®, FLEX 10KA, FLEX 10KE, and MercuryT devices.
Hope this helps.
- Subroto Datta
Altera Corp.