File:  [gforth] / gforth / vmgen-ex / mini.y
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Sun Mar 9 15:17:09 2003 UTC (16 years, 11 months ago) by anton
Branches: MAIN
CVS tags: v0-6-1, v0-6-0, HEAD
updated copyright years

    1: /* front-end compiler for vmgen example
    2: 
    3:   Copyright (C) 2001,2002 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: /* I use yacc/bison here not because I think it's the best tool for
   23:    the job, but because it's widely available and popular; it's also
   24:    (barely) adequate for this job. */
   25: 
   26: %{
   27: #include <stdlib.h>
   28: #include <stdio.h>
   29: #include <string.h>
   30: #include "mini.h"
   31: 
   32: /* BB_BOUNDARY is needed on basic blocks without a preceding VM branch */
   33: #define BB_BOUNDARY (last_compiled = NULL,  /* suppress peephole opt */ \
   34:                      block_insert(vmcodep)) /* for accurate profiling */
   35: 
   36: Inst *vm_prim;
   37: Inst *vmcodep;
   38: FILE *vm_out;
   39: int vm_debug;
   40: 
   41: void yyerror(char *s)
   42: {
   43:     fprintf (stderr, "%s: %d: %s\n", program_name, yylineno, s);
   44: }
   45: 
   46: #include "mini-gen.i"
   47: 
   48: void gen_main_end(void)
   49: {
   50:   gen_call(&vmcodep, func_addr("main"), func_calladjust("main"));
   51:   gen_end(&vmcodep);
   52:   BB_BOUNDARY; /* for profiling; see comment in mini.vmg:end */
   53: }
   54: 
   55: int locals=0;
   56: int nonparams=0;
   57: 
   58: int yylex();
   59: %}
   60: 
   61: 
   62: %token FUNC RETURN END VAR IF THEN ELSE WHILE DO BECOMES PRINT NUM IDENT
   63: 
   64: %union {
   65:   long num;
   66:   char *string;
   67:   Inst *instp;
   68: }
   69: 
   70: %type <string> IDENT;
   71: %type <num> NUM;
   72: %type <instp> elsepart;
   73: 
   74: 
   75: %%
   76: program: program function
   77:        | ;
   78: 
   79: function: FUNC IDENT { locals=0; nonparams=0; } '(' params ')' 
   80:           vars                  { insert_func($2,vmcodep,locals,nonparams); } 
   81:           stats RETURN expr ';'
   82:           END FUNC ';'          { gen_return(&vmcodep, -adjust(locals)); }
   83:         ;
   84: 
   85: params: IDENT ',' { insert_local($1); } params 
   86:       | IDENT     { insert_local($1); }
   87:       | ;
   88: 
   89: vars: vars VAR IDENT ';' { insert_local($3); nonparams++; }
   90:     | ;
   91: 
   92: stats: stats stat ';'
   93:      | ;
   94: 
   95: stat: IF expr THEN { gen_zbranch(&vmcodep, 0); $<instp>$ = vmcodep; }
   96:       stats { $<instp>$ = $<instp>4; } 
   97:       elsepart END IF { BB_BOUNDARY; $<instp>7[-1] = (Inst)vmcodep; }
   98:     | WHILE   { BB_BOUNDARY; $<instp>$ = vmcodep; } 
   99:       expr DO { gen_zbranch(&vmcodep, 0); $<instp>$ = vmcodep; }
  100:       stats END WHILE { gen_branch(&vmcodep, $<instp>2); $<instp>5[-1] = (Inst)vmcodep; }
  101:     | IDENT BECOMES expr	{ gen_storelocal(&vmcodep,  var_offset($1)); }
  102:     | PRINT expr		{ gen_print(&vmcodep); }
  103:     | expr                      { gen_drop(&vmcodep); }
  104:     ;
  105: 
  106: elsepart: ELSE { gen_branch(&vmcodep, 0); $<instp>$ = vmcodep; $<instp>0[-1] = (Inst)vmcodep; }
  107:           stats { $$ = $<instp>2; }
  108:         | { $$ = $<instp>0; }
  109:         ;
  110: 
  111: expr: term '+' term	 { gen_add(&vmcodep); }
  112:     | term '-' term	 { gen_sub(&vmcodep); }
  113:     | term '*' term	 { gen_mul(&vmcodep); }
  114:     | term '&' term	 { gen_and(&vmcodep); }
  115:     | term '|' term	 { gen_or(&vmcodep); }
  116:     | term '<' term	 { gen_lessthan(&vmcodep); }
  117:     | term '=' term	 { gen_equals(&vmcodep); }
  118:     | '!' term		 { gen_not(&vmcodep); }
  119:     | '-' term		 { gen_negate(&vmcodep); }
  120:     | term
  121:     ;
  122: 
  123: term: '(' expr ')'
  124:     | IDENT '(' args ')' { gen_call(&vmcodep, func_addr($1), func_calladjust($1)); }
  125:     | IDENT		 { gen_loadlocal(&vmcodep, var_offset($1)); }
  126:     | NUM		 { gen_lit(&vmcodep, $1); }
  127:     ;
  128: 
  129: /* missing: argument counting and checking against called function */
  130: args: expr ',' args
  131:     | expr 
  132:     | ;
  133: %%
  134: int yywrap(void)
  135: {
  136:   return 1;
  137: }
  138: 
  139: #include "lex.yy.c"

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