EP4SE360F35I4 Datasheet, PDF (61/432 Pages) Altera Corporation – This section provides a complete overview of all features relating to the Stratix IV device family, which is the most architecturlly advanced

Chapter 3: TriMatrix Embedded Memory Blocks in Stratix IV Devices
3–5
Overview
Packed Mode Support
Stratix IV M9K and M144K blocks support packed mode. The packed mode feature
packs two independent single-port RAMs into one memory block. The Quartus II
software automatically implements packed mode where appropriate by placing the
physical RAM block into true dual-port mode and using the MSB of the address to
distinguish between the two logical RAMs. The size of each independent single-port
RAM must not exceed half of the target block size.
December 2011 Altera Corporation
Stratix IV Device Handbook
Volume 1