152 lines
4.2 KiB
C
152 lines
4.2 KiB
C
/*
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* Copyright (c) 2000 Stephen Williams (steve@icarus.com)
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*
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* This source code is free software; you can redistribute it
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* and/or modify it in source code form under the terms of the GNU
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* General Public License as published by the Free Software
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* Foundation; either version 2 of the License, or (at your option)
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* any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
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*/
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#ifdef HAVE_CVS_IDENT
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#ident "$Id: fit_log.c,v 1.6 2007/02/26 19:49:50 steve Exp $"
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#endif
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# include "config.h"
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# include "ivl_target.h"
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# include <stdio.h>
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# include <stdlib.h>
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# include <assert.h>
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# include "priv.h"
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/*
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* By the time we get here, all the flip-flops have been placed in
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* macrocells, and enables attached to them. So all that's left is to
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* work backwards from each macrocell, making terms and sum-of-terms
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* from the asynchronous logic until we get to the table inputs.
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*
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* A product term is a null terminated array of ivl_nexus_t
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* objects. An expression is a null terminated array of terms.
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*/
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static void dump_expr(term_t**expr, const char*title)
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{
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unsigned idx;
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fprintf(stderr, "expression for %s:\n", title);
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for (idx = 0 ; expr[idx] ; idx += 1) {
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term_t*tp;
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fprintf(stderr, " term %u:\n", idx);
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for (tp = expr[idx] ; tp->nex ; tp += 1)
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fprintf(stderr, " %c%s\n", tp->inv? '~' : ' ',
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ivl_nexus_name(tp->nex));
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}
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}
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static term_t** build_expr(ivl_nexus_t nex)
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{
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term_t* term = calloc(2, sizeof(term_t));
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term_t**expr = calloc(2, sizeof(term_t*));
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unsigned idx;
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assert(nex);
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expr[0] = term;
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term[0].inv = 0;
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term[0].nex = nex;
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/* First look to see if I'm connected to an input pin. If so,
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then this expression is done. */
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for (idx = 0 ; idx < pins ; idx += 1) {
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struct pal_bind_s*pin = bind_pin + idx;
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if ((nex == pin->nexus) && (pin->sop == 0)) {
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return expr;
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}
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}
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fprintf(stderr, "sorry, I give up on nexus %s\n", ivl_nexus_name(nex));
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return 0;
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}
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int fit_logic(void)
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{
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unsigned idx;
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for (idx = 0 ; idx < pins ; idx += 1) {
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ivl_nexus_t cell;
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struct pal_bind_s*pin = bind_pin + idx;
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if (pin->sop == 0)
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continue;
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cell = pin->nexus;
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if (cell == 0)
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continue;
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/* If there is an enable, then this is a bufifX or a
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notifX. Build the expression for the enable, and
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guess that the input to the cell is actually the
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input to the enable. */
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if (pin->enable) {
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ivl_nexus_t en_nex = ivl_logic_pin(pin->enable, 2);
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assert(cell == ivl_logic_pin(pin->enable, 0));
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cell = ivl_logic_pin(pin->enable, 1);
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assert(cell);
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pin->enable_ex = build_expr(en_nex);
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dump_expr(pin->enable_ex, ivl_nexus_name(en_nex));
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}
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/* If there is a reg, then the input to the cell is
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really the D input to the ff. */
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if (pin->reg) {
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assert(cell == ivl_lpm_q(pin->reg, pin->reg_q));
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cell = ivl_lpm_data(pin->reg, pin->reg_q);
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}
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assert(cell);
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/* Here we are. Generate the sum-of-products for the
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input. */
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pin->sop_ex = build_expr(cell);
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dump_expr(pin->sop_ex, ivl_nexus_name(cell));
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}
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return 0;
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}
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/*
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* $Log: fit_log.c,v $
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* Revision 1.6 2007/02/26 19:49:50 steve
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* Spelling fixes (larry doolittle)
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*
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* Revision 1.5 2002/08/12 01:35:03 steve
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* conditional ident string using autoconfig.
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*
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* Revision 1.4 2001/07/25 03:10:50 steve
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* Create a config.h.in file to hold all the config
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* junk, and support gcc 3.0. (Stephan Boettcher)
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*
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* Revision 1.3 2001/05/16 03:55:30 steve
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* Update to new LPM API for flip-flops.
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*
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* Revision 1.2 2001/02/07 22:22:00 steve
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* ivl_target header search path fixes.
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*
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* Revision 1.1 2000/12/14 23:37:47 steve
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* Start support for fitting the logic.
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*
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*/
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