AR# 4886: A1.5/F1.5 MAP - Map will not put two SRL16 instances into a single Virtex CLB
A1.5/F1.5 MAP - Map will not put two SRL16 instances into a single Virtex CLB
The SRL16 symbol takes up less than half of the resources of a single Virtex CLB, yet MAP is only able to put one SRL16 per CLB, and nothing else. In this way, MAP uses twice as many CLBs as it should. Setting the RLOC attribute on two SRL16 instances to the same CLB will produce a, "fatal error... placement constraint cannot be met," error.
This problem is fixed in the M1.5i Performance Pack Update due to begin shipping in December 1998.