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Diffstat (limited to 'techlibs/xilinx/mux_map.v')
| -rw-r--r-- | techlibs/xilinx/mux_map.v | 71 |
1 files changed, 71 insertions, 0 deletions
diff --git a/techlibs/xilinx/mux_map.v b/techlibs/xilinx/mux_map.v new file mode 100644 index 000000000..91aaf2118 --- /dev/null +++ b/techlibs/xilinx/mux_map.v @@ -0,0 +1,71 @@ +/* + * yosys -- Yosys Open SYnthesis Suite + * + * Copyright (C) 2012 Clifford Wolf <clifford@clifford.at> + * 2019 Eddie Hung <eddie@fpgeh.com> + * + * Permission to use, copy, modify, and/or distribute this software for any + * purpose with or without fee is hereby granted, provided that the above + * copyright notice and this permission notice appear in all copies. + * + * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES + * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF + * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR + * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES + * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN + * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF + * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. + * + */ + +// The purpose of these mapping rules is to allow preserve all (sufficiently +// wide) $shiftx cells during 'techmap' so that they can be mapped to hard +// resources, rather than being bit-blasted to gates during 'techmap' +// execution + +module \$shiftx (A, B, Y); + parameter A_SIGNED = 0; + parameter B_SIGNED = 0; + parameter A_WIDTH = 1; + parameter B_WIDTH = 1; + parameter Y_WIDTH = 1; + + input [A_WIDTH-1:0] A; + input [B_WIDTH-1:0] B; + output [Y_WIDTH-1:0] Y; + + parameter [B_WIDTH-1:0] _TECHMAP_CONSTMSK_B_ = 0; + parameter [B_WIDTH-1:0] _TECHMAP_CONSTVAL_B_ = 0; + + generate + if (B_SIGNED) begin + if (_TECHMAP_CONSTMSK_B_[B_WIDTH-1] && (_TECHMAP_CONSTVAL_B_[B_WIDTH-1] == 1'b0 || _TECHMAP_CONSTVAL_B_[B_WIDTH-1] === 1'bx)) + // Optimisation to remove B_SIGNED if sign bit of B is constant-0 + \$shiftx #( + .A_SIGNED(A_SIGNED), + .B_SIGNED(0), + .A_WIDTH(A_WIDTH), + .B_WIDTH(B_WIDTH-1'd1), + .Y_WIDTH(Y_WIDTH) + ) _TECHMAP_REPLACE_ ( + .A(A), .B(B[B_WIDTH-2:0]), .Y(Y) + ); + else + wire _TECHMAP_FAIL_ = 1; + end + else begin + if (((A_WIDTH + Y_WIDTH - 1) / Y_WIDTH) < `MIN_MUX_INPUTS) + wire _TECHMAP_FAIL_ = 1; + else + \$__XILINX_SHIFTX #( + .A_SIGNED(A_SIGNED), + .B_SIGNED(B_SIGNED), + .A_WIDTH(A_WIDTH), + .B_WIDTH(B_WIDTH), + .Y_WIDTH(Y_WIDTH) + ) _TECHMAP_REPLACE_ ( + .A(A), .B(B), .Y(Y) + ); + end + endgenerate +endmodule |