MMIX assembly language floating point number preprocessor – GNU Bison and GNU Flex version
Here’s a GNU Bison and GNU Flex version of my MMIX assembly language floating point number preprocessor. The code was developed using GNU Bison version 1.875d and GNU Flex version 2.5.
This version allows for entering more complex expressions of floating point numbers involving addition, subtraction, multiplication and division. Extending the grammar to cover trigonometric functions and square root is left as an exercise to the reader.
* Here are some constants from Don Knuth's world: MIX FLOAT 1009 comments are still allowed MMIX FLOAT 2009 after the operand field * Here are some well known constants from the mathematical world: Pi FLOAT 3.14159265358979323846 TeX's ultimate version number e FLOAT 2.7182818284590452354 ditto for METAFONT * Here are lists of simple numbers and some irrational numbers: ListOfNumbers FLOAT 1,2,3 Expressions FLOAT 1/3,2/3 * 32-bit floating point numbers are also available. * But do not use them if you do not need them, * FLOATs have better properties than SINGLEs. MIX32 SINGLE 1009 MMIX32 SINGLE 2009 NextMMIX SINGLE 2009+1000 the next MMIX?
%{
/*
mmixalfpp-parser.y - yacc parser for mmixalfpp
Copyright © 2004 Trond Endrestøl <Trond.Endrestol@ximalas.info>
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the
Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston,
MA 02111-1307 USA.
*/
#define YYDEBUG 0
#define YYERROR_VERBOSE 1
#include <ctype.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
int yylex(void);
void yyerror(char const *);
void print_hex(double d);
#define isletter(c) (isalpha((c)) || (c) == '_' || (c) == ':' || (c) > 126)
#define iswhitespace(c) ((c) == ' ' || (c) == '\t')
enum floattype_t { SINGLE, FLOAT } floattype;
union { float f; unsigned char b[4]; } singleprec;
union { double d; unsigned char b[8]; } doubleprec;
FILE *infile, *outfile;
const size_t bufferlen = 1024;
unsigned char *buffer, *keyword, *comment, *p;
char *progname, *infilename;
extern int yylineno;
%}
%union {
double d;
}
%token <d> NUMBER
%token COMMA
%left MINUS PLUS
%left ASTERISK SLASH
%left UMINUS
%token LPAREN
%token RPAREN
%type <d> input
%type <d> expr
%%
input: expr { print_hex($1); }
| input COMMA expr { fputc(',', outfile); print_hex($3); }
| error expr { $$ = $2; yyerrok; }
;
expr: NUMBER { $$ = $1; }
| PLUS expr %prec UMINUS { $$ = $2; }
| MINUS expr %prec UMINUS { $$ = -$2; }
| expr PLUS expr { $$ = $1 + $3; }
| expr MINUS expr { $$ = $1 - $3; }
| expr ASTERISK expr { $$ = $1 * $3; }
| expr SLASH expr { $$ = $1 / $3; }
| LPAREN expr RPAREN { $$ = $2; }
| LPAREN error RPAREN { yyerrok; }
;
%%
void yyerror(char const *s)
{
fprintf(stderr,
"%s: %s: %d: %s\n",
progname, infilename, yylineno, s);
} /* yyerror() */
void print_hex(double d)
{
fputc('#', outfile);
if (floattype == FLOAT) {
doubleprec.d = d;
#if BYTE_ORDER == LITTLE_ENDIAN
fprintf(outfile, "%02x%02x%02x%02x%02x%02x%02x%02x",
doubleprec.b[7], doubleprec.b[6], doubleprec.b[5], doubleprec.b[4],
doubleprec.b[3], doubleprec.b[2], doubleprec.b[1], doubleprec.b[0]);
#elif BYTE_ORDER == BIG_ENDIAN
fprintf(outfile, "%02x%02x%02x%02x%02x%02x%02x%02x",
doubleprec.b[0], doubleprec.b[1], doubleprec.b[2], doubleprec.b[3],
doubleprec.b[4], doubleprec.b[5], doubleprec.b[6], doubleprec.b[7]);
#else
#error unknown endian
#endif
} /* if */
else {
singleprec.f = d;
#if BYTE_ORDER == LITTLE_ENDIAN
fprintf(outfile, "%02x%02x%02x%02x",
singleprec.b[3], singleprec.b[2], singleprec.b[1], singleprec.b[0]);
#elif BYTE_ORDER == BIG_ENDIAN
fprintf(outfile, "%02x%02x%02x%02x",
singleprec.b[0], singleprec.b[1], singleprec.b[2], singleprec.b[3]);
#endif
} /* else*/
} /* print_hex() */
void process_line(void)
{
p = buffer;
while (p != keyword) { /* Print all before keyword */
fputc(*p++, outfile);
} /* while */
p += 5; /* Skip keyword */
if (floattype == FLOAT) {
fputs("OCTA", outfile);
} /* if */
else {
p++; /* Skip the E in SINGLE */
fputs("TETRA", outfile);
} /* else */
while (iswhitespace(*p)) { /* Print the whitespace after the keyword */
fputc(*p++, outfile);
} /* while */
if ( (comment = strchr(p, '\t')) == NULL) { /* Scan for the comment field, a newline, or EOL */
if ( (comment = strchr(p, ' ')) == NULL) {
if ( (comment = strchr(p, '\n')) == NULL) {
comment = strchr(p, '\0');
} /* if */
} /* if */
} /* if */
yyparse(); /* Get the ball running */
while (*p != '\0') { /* Print the remainder of the line, if any */
fputc(*p++, outfile);
} /* while */
} /* process_line() */
int main(int argc, char **argv)
{
progname = argv[0];
if (argc < 3) {
fprintf(stderr, "Usage: %s <infile | - > <outfile | - >\n", progname);
return EXIT_FAILURE;
} /* if */
if (!strcmp(argv[1], "-")) {
infile = stdin;
infilename = "stdin";
} /* if */
else {
infilename = argv[1];
if ( (infile = fopen(infilename, "r")) == NULL) {
fprintf(stderr, "%s: could not open %s for reading\n", progname, infilename);
return EXIT_FAILURE;
} /* if */
} /* else */
if (!strcmp(argv[2], "-")) {
outfile = stdout;
} /* if */
else {
if ( (outfile = fopen(argv[2], "w")) == NULL) {
fprintf(stderr, "%s: could not open %s for writing\n", progname, argv[2]);
return EXIT_FAILURE;
} /* if */
} /* else */
if ( (buffer = malloc(bufferlen * sizeof(char))) == NULL) {
fprintf(stderr,
"%s: could not allocate %lu bytes for buffer\n",
progname, (unsigned long)bufferlen);
return EXIT_FAILURE;
} /* if */
while (!feof(infile)) { /* Read until the end of infile */
if (fgets(buffer, bufferlen, infile) == NULL) { /* Read the next line from infile */
if (feof(infile)) { /* We are at the end of infile */
return EXIT_SUCCESS; /* Everything is OK */
} /* if */
else {
fprintf(stderr,
"%s: could not read line from %s\n",
progname, argv[1]);
return EXIT_FAILURE;
} /* else */
} /* if */
if (isletter(buffer[0]) || isdigit(buffer[0]) || iswhitespace(buffer[0])) { /* This line is not a comment */
if ( (keyword = strstr(buffer, "FLOAT")) != NULL) { /* Found FLOAT */
floattype = FLOAT;
process_line();
} /* if */
else if ( (keyword = strstr(buffer, "SINGLE")) != NULL) { /* Found SINGLE */
floattype = SINGLE;
process_line();
} /* else if */
else { /* This line does not contain SINGLE nor FLOAT */
fputs(buffer, outfile);
} /* else*/
} /* if */
else { /* This line is a comment */
fputs(buffer, outfile);
} /* else */
yylineno++;
} /* while */
/* NOTREACHED */
return EXIT_SUCCESS;
} /* main() */
/* End of mmixalfpp-parser.y */
/*
mmixalfpp-lexer.l - lexer for mmixalfpp
Copyright © 2004 Trond Endrestøl <Trond.Endrestol@ximalas.info>
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the
Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston,
MA 02111-1307 USA.
*/
%{
#include "mmixalfpp-parser.h"
#include <stdio.h>
extern unsigned char *comment, *p;
#define YY_INPUT(buf,result,max_size) \
{ \
result = (p == comment) ? YY_NULL : (buf[0] = *p++, 1); \
}
%}
%option 8bit
%option case-sensitive
%option noyywrap
%option yylineno
digit [0-9]
number1 {digit}+\.?([eE][-+]?{digit}+)?
number2 {digit}*\.{digit}+([eE][-+]?{digit}+)?
number {number1}|{number2}
%%
{number} yylval.d = atof(yytext); return NUMBER;
"," yylval.d = 0; return COMMA;
"+" yylval.d = 0; return PLUS;
"-" yylval.d = 0; return MINUS;
"*" yylval.d = 0; return ASTERISK;
"/" yylval.d = 0; return SLASH;
"(" yylval.d = 0; return LPAREN;
")" yylval.d = 0; return RPAREN;
%%
/* End of mmixalfpp-lexer.l */