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M1.3/M1.4 MAP, XC4000EX CCxxCLE counter library macros: WARNING:x4kma - Signal xxx on pin G4 of CY4 symbol is not required by carry mode INC-F-CI


Record #2249

Product Family:  Software

Product Line:  Merged Core

Problem Title:
M1.3/M1.4 MAP, XC4000EX CCxxCLE counter library macros: WARNING:x4kma -
Signal xxx on pin G4 of CY4 symbol is not required by carry mode INC-F-CI



Problem Description:
Keywords: library macro x4kma carry logic, cy4, cc16cle

Urgency: standard

General Description:

Users may see a warning similar to the following on
Xilinx library macros that utilize the INC-FG-CI carry logic
mode (CC8CE, CC8CLE, CC16CLE, etc.):

WARNING:x4kma - Signal `Q15_OUT' on pin G4 of CY4 symbol
`$1I17/$1I141' (output signal=$1I17/C14) is not required by
carry mode INC-F-CI.  The signal is being removed.


Solution 1:

This is a known problem with the M1.3 design entry libraries.
The warning is valid, and the trimming of the extraneous
signal should not be cause for concern.

MAP is simply optimizing the INC-FG-CI mode carry logic into
INC-F-CI and removing unecessary signals.

The warning may not be meaningful at first glance because
the optimization from INC-FG-CI to INC-F-CI that occurs
before the signals are actually trimmed is reported in a
separate section of the Map .MRP report.  However, the
trimming is valid.

Reference:  16683



End of Record #2249