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Annotation of gforth/vmgen-ex/mini.y, revision 1.3

1.1       anton       1: /* front-end compiler for vmgen example
                      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: /* 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; } 
1.3     ! anton      97:       elsepart END IF { BB_BOUNDARY; $<instp>7[-1] = (Inst)vmcodep; }
1.1       anton      98:     | WHILE   { BB_BOUNDARY; $<instp>$ = vmcodep; } 
                     99:       expr DO { gen_zbranch(&vmcodep, 0); $<instp>$ = vmcodep; }
1.3     ! anton     100:       stats END WHILE { gen_branch(&vmcodep, $<instp>2); $<instp>5[-1] = (Inst)vmcodep; }
1.1       anton     101:     | IDENT BECOMES expr       { gen_storelocal(&vmcodep,  var_offset($1)); }
                    102:     | PRINT expr               { gen_print(&vmcodep); }
                    103:     | expr                      { gen_drop(&vmcodep); }
                    104:     ;
                    105: 
1.3     ! anton     106: elsepart: ELSE { gen_branch(&vmcodep, 0); $<instp>$ = vmcodep; $<instp>0[-1] = (Inst)vmcodep; }
1.1       anton     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: 
1.2       anton     129: /* missing: argument counting and checking against called function */
1.1       anton     130: args: expr ',' args
                    131:     | expr 
                    132:     | ;
                    133: %%
                    134: int yywrap(void)
                    135: {
                    136:   return 1;
                    137: }
                    138: 
                    139: #include "lex.yy.c"