Annotation of gforth/vmgen-ex2/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 <stdlib.h>
! 23: #include "mini.h"
! 24:
! 25: /* the numbers in this struct are primitive indices */
! 26: typedef struct Combination {
! 27: int prefix;
! 28: int lastprim;
! 29: int combination_prim;
! 30: } Combination;
! 31:
! 32: Combination peephole_table[] = {
! 33: #include "mini-peephole.i"
! 34: };
! 35:
! 36: int use_super = 1;
! 37:
! 38: typedef struct Peeptable_entry {
! 39: struct Peeptable_entry *next;
! 40: Label prefix;
! 41: Label lastprim;
! 42: Label combination_prim;
! 43: } Peeptable_entry;
! 44:
! 45: #define HASH_SIZE 1024
! 46: #define hash(_i1,_i2) (((((long)(_i1))^((long)(_i2)))>>4)&(HASH_SIZE-1))
! 47:
! 48: struct Peeptable_entry **peeptable;
! 49:
! 50: Peeptable_entry **prepare_peephole_table(Label insts[])
! 51: {
! 52: long i;
! 53: Peeptable_entry **pt = (Peeptable_entry **)calloc(HASH_SIZE,sizeof(Peeptable_entry *));
! 54:
! 55: for (i=0; i<sizeof(peephole_table)/sizeof(peephole_table[0]); i++) {
! 56: Combination *c = &peephole_table[i];
! 57: Peeptable_entry *p = (Peeptable_entry *)malloc(sizeof(Peeptable_entry));
! 58: long h;
! 59: p->prefix = insts[c->prefix];
! 60: p->lastprim = insts[c->lastprim];
! 61: p->combination_prim = insts[c->combination_prim];
! 62: h = hash((p->prefix),(p->lastprim));
! 63: p->next = pt[h];
! 64: pt[h] = p;
! 65: }
! 66: return pt;
! 67: }
! 68:
! 69: void init_peeptable(void)
! 70: {
! 71: peeptable = prepare_peephole_table(vm_prim);
! 72: }
! 73:
! 74: Label peephole_opt(Label inst1, Label inst2, Peeptable_entry **peeptable)
! 75: {
! 76: Peeptable_entry **pt = (Peeptable_entry **)peeptable;
! 77: Peeptable_entry *p;
! 78:
! 79: if (use_super == 0)
! 80: return NULL;
! 81: for (p = pt[hash(inst1,inst2)]; p != NULL; p = p->next)
! 82: if (inst1 == p->prefix && inst2 == p->lastprim)
! 83: return p->combination_prim;
! 84: return NULL;
! 85: }
! 86:
! 87: Inst *last_compiled = NULL;
! 88:
! 89: void gen_inst(Inst **vmcodepp, Label i)
! 90: {
! 91: if (last_compiled != NULL) {
! 92: Label combo = peephole_opt((*last_compiled).inst, i, peeptable);
! 93: if (combo != NULL) {
! 94: (*last_compiled).inst = combo;
! 95: return;
! 96: }
! 97: }
! 98: last_compiled = *vmcodepp;
! 99: (**vmcodepp).inst = i;
! 100: (*vmcodepp)++;
! 101: }
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