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Annotation of gforth/engine/peephole.c, revision 1.2

1.1       anton       1: /* Peephole optimization routines and tables
                      2: 
                      3:   Copyright (C) 2001 Free Software Foundation, Inc.
                      4: 
                      5:   This file is part of Gforth.
                      6: 
                      7:   Gforth is free software; you can redistribute it and/or
                      8:   modify it under the terms of the GNU General Public License
                      9:   as published by the Free Software Foundation; either version 2
                     10:   of the License, or (at your option) any later version.
                     11: 
                     12:   This program is distributed in the hope that it will be useful,
                     13:   but WITHOUT ANY WARRANTY; without even the implied warranty of
                     14:   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
                     15:   GNU General Public License for more details.
                     16: 
                     17:   You should have received a copy of the GNU General Public License
                     18:   along with this program; if not, write to the Free Software
                     19:   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111, USA.
                     20: */
                     21: 
                     22: #include "config.h"
                     23: #include "forth.h"
1.2     ! anton      24: #include <stdlib.h>
1.1       anton      25: 
                     26: /* the numbers in this struct are primitive indices */
                     27: typedef struct Combination {
                     28:   int prefix;
                     29:   int lastprim;
                     30:   int combination_prim;
                     31: } Combination;
                     32: 
                     33: Combination peephole_table[] = {
                     34: #include "peephole.i"
                     35: };
                     36: 
                     37: Xt *primtable(Label symbols[], Cell size)
                     38: {
                     39: #ifdef DIRECT_THREADED
                     40:   return symbols;
                     41: #else /* !defined(DIRECT_THREADED) */
                     42:   Xt *xts = (Xt *)malloc(size*sizeof(Xt));
                     43:   Cell i;
                     44: 
                     45:   for (i=0; i<size; i++)
                     46:     xts[i] = &symbols[i];
                     47:   return xts;
                     48: #endif /* !defined(DIRECT_THREADED) */
                     49: }
                     50: 
                     51: /* we are currently using a simple linear search; we can refine this
                     52:    once the interface has settled and this works */
                     53: 
                     54: Cell prepare_peephole_table(Xt xts[])
                     55: {
                     56:   return (Cell)xts;
                     57: }
                     58: 
                     59: Xt peephole_opt(Xt xt1, Xt xt2, Cell peeptable)
                     60: {
                     61:   Xt *xts = (Xt *)peeptable;
                     62:   Cell i;
                     63: 
                     64:   for (i=0; i<(sizeof(peephole_table)/sizeof(Combination)); i++) {
                     65:     Combination *c = &peephole_table[i];
                     66:     if (xt1 == xts[c->prefix] && xt2 == xts[c->lastprim])
                     67:       return xts[c->combination_prim];
                     68:   }
                     69:   return 0;
                     70: }