Annotation of gforth/engine/peephole.c, revision 1.1

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"
        !            24: #include "stdlib.h"
        !            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: }

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