AR# 12306: 4.1i Virtex-E MAP - Area group constraints are handled differently between 3.1i and 4.1i.
4.1i Virtex-E MAP - Area group constraints are handled differently between 3.1i and 4.1i.
Keywords: range, area, groups, placer, placed
General Description: The 3.1i release contained an unintended feature that allowed users to apply multiple range constraints to an area group:
For example: INST wc_ibhttp AREA_GROUP = FPAG_wc_ibhttp ; AREA_GROUP FPAG_wc_ibhttp RANGE CLB_R34C23:CLB_R63C30 ; AREA_GROUP FPAG_wc_ibhttp RANGE CLB_R34C31:CLB_R103C54 ; AREA_GROUP FPAG_wc_ibhttp RANGE CLB_R34C55:CLB_R60C70 ;
The 3.1i MAP and PAR tools processed these multiple ranges and used all of the areas listed. As a result, the functionality is equivalent to a "list of ranges" constraint that allows the user to define a non-rectangular placement area.
NOTE: This "feature" can handle only three concurrent ranges, and the area group must only contain slice components. This is because the extra range definitions overwrite an area that is reserved for other component types.