furnace/extern/fftw/genfft/gen_hc2c.ml

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(*
* Copyright (c) 1997-1999 Massachusetts Institute of Technology
* Copyright (c) 2003, 2007-14 Matteo Frigo
* Copyright (c) 2003, 2007-14 Massachusetts Institute of Technology
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*
*)
open Util
open Genutil
open C
type ditdif = DIT | DIF
let ditdif = ref DIT
let usage = "Usage: " ^ Sys.argv.(0) ^ " -n <number> [ -dit | -dif ]"
let urs = ref Stride_variable
let speclist = [
"-dit",
Arg.Unit(fun () -> ditdif := DIT),
" generate a DIT codelet";
"-dif",
Arg.Unit(fun () -> ditdif := DIF),
" generate a DIF codelet";
"-with-rs",
Arg.String(fun x -> urs := arg_to_stride x),
" specialize for given R-stride";
]
let byi = Complex.times Complex.i
let byui = Complex.times (Complex.uminus Complex.i)
let sym n f i = if (i < n - i) then f i else Complex.conj (f i)
let shuffle_eo fe fo i = if i mod 2 == 0 then fe (i/2) else fo ((i-1)/2)
let generate n =
let rs = "rs"
and twarray = "W"
and m = "m" and mb = "mb" and me = "me" and ms = "ms"
(* the array names are from the point of view of the complex array
(output in R2C, input in C2R) *)
and arp = "Rp" (* real, positive *)
and aip = "Ip" (* imag, positive *)
and arm = "Rm" (* real, negative *)
and aim = "Im" (* imag, negative *)
in
let sign = !Genutil.sign
and name = !Magic.codelet_name
and byvl x = choose_simd x (ctimes (CVar "VL", x)) in
let (bytwiddle, num_twiddles, twdesc) = Twiddle.twiddle_policy 1 false in
let nt = num_twiddles n in
let byw = bytwiddle n sign (twiddle_array nt twarray) in
let vrs = either_stride (!urs) (C.SVar rs) in
(* assume a single location. No point in doing alias analysis *)
let the_location = (Unique.make (), Unique.make ()) in
let locations _ = the_location in
let locr = (locative_array_c n
(C.array_subscript arp vrs)
(C.array_subscript arm vrs)
locations "BUG")
and loci = (locative_array_c n
(C.array_subscript aip vrs)
(C.array_subscript aim vrs)
locations "BUG")
and locp = (locative_array_c n
(C.array_subscript arp vrs)
(C.array_subscript aip vrs)
locations "BUG")
and locm = (locative_array_c n
(C.array_subscript arm vrs)
(C.array_subscript aim vrs)
locations "BUG")
in
let locri i = if i mod 2 == 0 then locr (i/2) else loci ((i-1)/2)
and locpm i = if i < n - i then locp i else locm (n-1-i)
in
let asch =
match !ditdif with
| DIT ->
let output = Fft.dft sign n (byw (load_array_c n locri)) in
let odag = store_array_c n locpm (sym n output) in
standard_optimizer odag
| DIF ->
let output = byw (Fft.dft sign n (sym n (load_array_c n locpm))) in
let odag = store_array_c n locri output in
standard_optimizer odag
in
let vms = CVar "ms"
and varp = CVar arp
and vaip = CVar aip
and varm = CVar arm
and vaim = CVar aim
and vm = CVar m and vmb = CVar mb and vme = CVar me
in
let body = Block (
[Decl ("INT", m)],
[For (list_to_comma
[Expr_assign (vm, vmb);
Expr_assign (CVar twarray,
CPlus [CVar twarray;
ctimes (CPlus [vmb; CUminus (Integer 1)],
Integer nt)])],
Binop (" < ", vm, vme),
list_to_comma
[Expr_assign (vm, CPlus [vm; byvl (Integer 1)]);
Expr_assign (varp, CPlus [varp; byvl vms]);
Expr_assign (vaip, CPlus [vaip; byvl vms]);
Expr_assign (varm, CPlus [varm; CUminus (byvl vms)]);
Expr_assign (vaim, CPlus [vaim; CUminus (byvl vms)]);
Expr_assign (CVar twarray, CPlus [CVar twarray;
byvl (Integer nt)]);
make_volatile_stride (4*n) (CVar rs)
],
Asch asch)])
in
let tree =
Fcn ("static void", name,
[Decl (C.realtypep, arp);
Decl (C.realtypep, aip);
Decl (C.realtypep, arm);
Decl (C.realtypep, aim);
Decl (C.constrealtypep, twarray);
Decl (C.stridetype, rs);
Decl ("INT", mb);
Decl ("INT", me);
Decl ("INT", ms)],
finalize_fcn body)
in
let twinstr =
Printf.sprintf "static const tw_instr twinstr[] = %s;\n\n"
(twinstr_to_string "VL" (twdesc n))
and desc =
Printf.sprintf
"static const hc2c_desc desc = {%d, \"%s\", twinstr, &GENUS, %s};\n\n"
n name (flops_of tree)
and register = "X(khc2c_register)"
in
let init =
"\n" ^
twinstr ^
desc ^
(declare_register_fcn name) ^
(Printf.sprintf "{\n%s(p, %s, &desc, HC2C_VIA_RDFT);\n}" register name)
in
(unparse tree) ^ "\n" ^ init
let main () =
begin
parse (speclist @ Twiddle.speclist) usage;
print_string (generate (check_size ()));
end
let _ = main()