1 /*
2 * Copyright (c) 2013 Stephen Williams (steve@icarus.com)
3 *
4 * This source code is free software; you can redistribute it
5 * and/or modify it in source code form under the terms of the GNU
6 * General Public License as published by the Free Software
7 * Foundation; either version 2 of the License, or (at your option)
8 * any later version.
9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
14 *
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, write to the Free Software
17 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
18 */
19
20 # include "priv.h"
21 # include "nex_data.h"
22 # include <cassert>
23
24 using namespace std;
25
print_lpm_ff(FILE * fd,ivl_lpm_t net)26 int print_lpm_ff(FILE*fd, ivl_lpm_t net)
27 {
28 int errors = 0;
29
30 ivl_nexus_t nex_q = ivl_lpm_q(net);
31 blif_nex_data_t*ned_q = blif_nex_data_t::get_nex_data(nex_q);
32
33 ivl_nexus_t nex_d = ivl_lpm_data(net,0);
34 blif_nex_data_t*ned_d = blif_nex_data_t::get_nex_data(nex_d);
35
36 ivl_nexus_t nex_c = ivl_lpm_clk(net);
37 blif_nex_data_t*ned_c = blif_nex_data_t::get_nex_data(nex_c);
38
39 ivl_nexus_t nex_ce = ivl_lpm_enable(net);
40 blif_nex_data_t*ned_ce = nex_ce? blif_nex_data_t::get_nex_data(nex_ce) : 0;
41
42 if (ivl_lpm_async_clr(net)) {
43 errors += 1;
44 fprintf(stderr, "%s:%u: sorry: blif: Asynchronous clear not implemented yet\n",
45 ivl_lpm_file(net), ivl_lpm_lineno(net));
46 }
47
48 if (ivl_lpm_async_set(net)) {
49 errors += 1;
50 fprintf(stderr, "%s:%u: sorry: blif: Asynchronous set not implemented yet\n",
51 ivl_lpm_file(net), ivl_lpm_lineno(net));
52 }
53
54 fprintf(fd, "# IVL_LPM_FF: width=%u, Q=%s, D=%s, C=%s, CE=%s\n",
55 ivl_lpm_width(net), ned_q->get_name(), ned_d->get_name(), ned_c->get_name(), ned_ce? ned_ce->get_name() : "N/A");
56
57 if (ned_ce) {
58 // If there is a clock-enable, rewrite this in a form
59 // that blif can accept. Transform this:
60 //
61 // always @(posedge C) if (CE) Q <= D;
62 //
63 // to this:
64 //
65 // always @(posedge C) Q <= CE? D : Q;
66 //
67 // In ASIC-land, this is probably OK.
68 for (unsigned wid = 0 ; wid < ivl_lpm_width(net) ; wid += 1) {
69 fprintf(fd, ".names %s%s %s%s %s%s %s%s/EN\n"
70 "0-1 1\n"
71 "11- 1\n",
72 ned_ce->get_name(), ned_ce->get_name_index(0),
73 ned_d ->get_name(), ned_d ->get_name_index(wid),
74 ned_q ->get_name(), ned_q ->get_name_index(wid),
75 ned_d ->get_name(), ned_d ->get_name_index(wid));
76
77 fprintf(fd, ".latch %s%s/EN %s%s re %s%s 3\n",
78 ned_d->get_name(), ned_d->get_name_index(wid),
79 ned_q->get_name(), ned_q->get_name_index(wid),
80 ned_c->get_name(), ned_c->get_name_index(0));
81 }
82 } else {
83 for (unsigned wid = 0 ; wid < ivl_lpm_width(net) ; wid += 1) {
84 fprintf(fd, ".latch %s%s %s%s re %s%s 3\n",
85 ned_d->get_name(), ned_d->get_name_index(wid),
86 ned_q->get_name(), ned_q->get_name_index(wid),
87 ned_c->get_name(), ned_c->get_name_index(0));
88 }
89 }
90
91 return errors;
92 }
93