Gowin. Reduce the range of flip-flop types.

UG303-1.0E_Arora Ⅴ Configurable Function Unit (CFU) User Guide.pdf
specifies that the only flip-flop types supported in GW5 are DFFSE,
DFFRE, DFFPE, and DFFCE.

However, the bit streams generated by the vendor IDE also contain DFF
flip-flops, which are probably the result of optimisation, so we leave
them in the list of permitted items, but add a flag that will allow the
generation of completely correct output files, acceptable for further P&
R using vendor tools (they will not allow the use of flip-flops other
than the four specified in the netlist).

In the GW5 SemiDual Port BSRAM series, the primitive does not have
RESETA and RESETB ports—they are replaced by the RESET port, so we
separate the files for BSRAM generation, especially since in the future
we may have to take into account other, as yet unexplored, differences
in BSRAM.

Signed-off-by: YRabbit <rabbit@yrabbit.cyou>

Author: yrabbit

techlibs/gowin/Makefile.inc

@@ -8,6 +8,7 @@ $(eval $(call add_share_file,share/gowin,techlibs/gowin/cells_xtra_gw2a.v))
 $(eval $(call add_share_file,share/gowin,techlibs/gowin/cells_xtra_gw5a.v))
 $(eval $(call add_share_file,share/gowin,techlibs/gowin/arith_map.v))
 $(eval $(call add_share_file,share/gowin,techlibs/gowin/brams_map.v))
+$(eval $(call add_share_file,share/gowin,techlibs/gowin/brams_map_gw5a.v))
 $(eval $(call add_share_file,share/gowin,techlibs/gowin/brams.txt))
 $(eval $(call add_share_file,share/gowin,techlibs/gowin/lutrams_map.v))
 $(eval $(call add_share_file,share/gowin,techlibs/gowin/lutrams.txt))