ack/util/ceg/as_parser/pars.g
1989-01-26 14:47:03 +00:00

202 lines
4 KiB
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/* This file contains the description of the 'as_table' parser.
* It transforms every entry into a C-funtion, for example :
*
* and dst:REG, src:EADDR ==> @text1( 0x23);
* mod_RM( dst->reg, src).
*
* ... dst:ACCU, src:DATA ==> @text1( 0x25);
* @text2(
* %$(src->expr)).
*
* Will be transformed into :
*
* and_instr( dst, src)
* struct t_operand *dst, *src;
* {
* if ( REG( dst) && EADDR( src)) {
* cur_pos += 1;
* fprint( outfile, "text1( 0x23)");
* fprint( outfile, ";");
* mod_RM( dst->reg, src);
* }
* else if ( ACCU( dst) && DATA( src)) {
* cur_pos += 1;
* fprint( outfile, "text1( 0x25)");
* fprint( outfile, ";");
* cur_pos += 2;
* fprint( outfile, "text2( ");
* eval( src->expr);
* fprint( outfile, ")");
* fprint( outfile, ";");
* }
* else
* error( "No match for and");
* }
*
* At the end of the table a list is generated enumerating all the assembler
* mnemonics and their corresponding function names.
*/
{
#include "decl.h"
extern int yylineno, yyleng, yymorfg;
extern char yytext[];
}
%token IDENTIFIER, CALL, CONDITION, IF, ELSIF, ELSE, FI, ARROW, MORE;
%start table, table;
%lexical lex_analyzer ;
table : { init_table();}
instruction* { end_table();}
;
instruction : { clean();}
first_row
[ { operand_clean();}
extra_row
]* { pr_warning(); out( "}\n\n");}
;
first_row : mnemonic { save_instr( yytext, yyleng);}
[ decl_list]?
ARROW { pr_header(); pr_restriction();}
action_list
;
extra_row : MORE
[ decl_list]?
ARROW { out( "else "); pr_restriction();}
action_list
;
mnemonic : IDENTIFIER
;
decl_list : { clear_restriction();}
declaration
[ ',' declaration] *7
;
declaration : IDENTIFIER { save_name( yytext, yyleng);}
[ ':'
IDENTIFIER { save_type( yytext, yyleng);}
]? { inc_ops();}
;
action_list : { out( "{\n");}
[ action [ ';' action]* ]? '.' { out( "}\n");}
;
action : if_statement
| call
| subroutine
;
/* A function call is just an identifier followed by an expression surrounded
* by '(' and ')'. CONDITION is a token that matches this construct;
*/
subroutine : IDENTIFIER { yymorfg=1;}
CONDITION { pr_subroutine( yytext);}
;
call : '@'
IDENTIFIER { yymorfg=1;}
CONDITION { pr_call( yytext);}
;
if_statement : IF
CONDITION { pr_question( yytext);}
action_list { pr_end();}
[ ELSIF { pr_els();}
CONDITION { pr_question( yytext);}
action_list { pr_end();}
]*
[ ELSE { pr_else();}
action_list { pr_end();}
]?
FI
;
{
int nerrors;
static int saved = 0, token;
LLmessage( inserted_token)
int inserted_token;
{
nerrors++;
if ( inserted_token == 0) {
fprint( STDERR, "Sytax error in line %d, ", yylineno);
print_token( LLsymb);
fprint( STDERR, " will be deleted!!\n");
}
else if ( inserted_token < 0) {
fprint( STDERR, "Garbage at end, line %d!!\n",
yylineno);
}
else {
fprint( STDERR, "Sytax error in line %d, ", yylineno);
print_token( inserted_token);
fprint( STDERR, " will be inserted!!\n");
token = LLsymb;
saved = 1;
}
}
print_token( token)
int token;
{
switch ( token) {
case IDENTIFIER : fprint( STDERR, "IDENTIFIER %s", yytext);
break;
case CALL : fprint( STDERR, "CALL %s", yytext);
break;
case CONDITION: fprint( STDERR, "CONDITION %s", yytext);
break;
case IF : fprint( STDERR, "@if ");
break;
case ELSIF : fprint( STDERR, "@elsif ");
break;
case ELSE : fprint( STDERR, "@else ");
break;
case FI : fprint( STDERR, "@fi ");
break;
case ARROW : fprint( STDERR, "==> ");
break;
case MORE : fprint( STDERR, "... ");
break;
default : fprint( STDERR, "%c ", token);
break;
}
}
int lex_analyzer()
{
int tok;
if ( saved) {
saved = 0;
return( token);
}
else {
tok = yylex();
yytext[yyleng] = '\0'; /* strings must end with '\0' */
return( tok);
}
}
main()
{
table();
exit(nerrors);
}
}