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techmap: Split out Kogge-Stone into a separate file

This commit is contained in:
Martin Povišer 2024-03-25 18:39:55 +01:00
parent c38201e15d
commit 4570d064e5
3 changed files with 55 additions and 10 deletions
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1
techlibs/common/Makefile.inc
View File

@ -35,3 +35,4 @@ $(eval $(call add_share_file,share,techlibs/common/abc9_map.v))
$(eval $(call add_share_file,share,techlibs/common/abc9_unmap.v))
$(eval $(call add_share_file,share,techlibs/common/cmp2lcu.v))
$(eval $(call add_share_file,share,techlibs/common/cmp2softlogic.v))
$(eval $(call add_share_file,share/choices,techlibs/common/choices/kogge-stone.v))

53
techlibs/common/choices/kogge-stone.v Normal file
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@ -0,0 +1,53 @@
/*
* yosys -- Yosys Open SYnthesis Suite
*
* Copyright (C) 2024 Martin Povišer <povik@cutebit.org>
*
* 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.
*
*/
(* techmap_celltype = "$lcu" *)
module _80_lcu_kogge_stone (P, G, CI, CO);
parameter WIDTH = 2;
(* force_downto *)
input [WIDTH-1:0] P, G;
input CI;
(* force_downto *)
output [WIDTH-1:0] CO;
integer i, j;
(* force_downto *)
reg [WIDTH-1:0] p, g;
wire [1023:0] _TECHMAP_DO_ = "proc; opt -fast";
always @* begin
p = P;
g = G;
// in almost all cases CI will be constant zero
g[0] = g[0] | (p[0] & CI);
for (i = 0; i < $clog2(WIDTH); i = i + 1) begin
for (j = 2**i; j < WIDTH; j = j + 1) begin
g[j] = g[j] | p[j] & g[j - 2**i];
p[j] = p[j] & p[j - 2**i];
end
end
end
assign CO = g;
endmodule

11
techlibs/common/techmap.v
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@ -207,7 +207,7 @@ module _90_fa (A, B, C, X, Y);
endmodule
(* techmap_celltype = "$lcu" *)
module _90_lcu (P, G, CI, CO);
module _90_lcu_brent_kung (P, G, CI, CO);
parameter WIDTH = 2;
(* force_downto *)
@ -230,7 +230,6 @@ module _90_lcu (P, G, CI, CO);
// in almost all cases CI will be constant zero
g[0] = g[0] | (p[0] & CI);
`ifndef KOGGE_STONE
// [[CITE]] Brent Kung Adder
// R. P. Brent and H. T. Kung, "A Regular Layout for Parallel Adders",
// IEEE Transaction on Computers, Vol. C-31, No. 3, p. 260-264, March, 1982
@ -250,14 +249,6 @@ module _90_lcu (P, G, CI, CO);
p[j] = p[j] & p[j - 2**(i-1)];
end
end
`else
for (i = 0; i < $clog2(WIDTH); i = i + 1) begin
for (j = 2**i; j < WIDTH; j = j + 1) begin
g[j] = g[j] | p[j] & g[j - 2**i];
p[j] = p[j] & p[j - 2**i];
end
end
`endif
end
assign CO = g;