/* Copyright (C) 1989, 1995, 1996, 1998 Aladdin Enterprises.  All rights reserved.

   This file is part of Aladdin Ghostscript.

   Aladdin Ghostscript is distributed with NO WARRANTY OF ANY KIND.  No author
   or distributor accepts any responsibility for the consequences of using it,
   or for whether it serves any particular purpose or works at all, unless he
   or she says so in writing.  Refer to the Aladdin Ghostscript Free Public
   License (the "License") for full details.

   Every copy of Aladdin Ghostscript must include a copy of the License,
   normally in a plain ASCII text file named PUBLIC.  The License grants you
   the right to copy, modify and redistribute Aladdin Ghostscript, but only
   under certain conditions described in the License.  Among other things, the
   License requires that the copyright notice and this notice be preserved on
   all copies.
 */

/*$Id: genarch.c $ */
/* Generate a header file (arch.h) with parameters */
/* reflecting the machine architecture and compiler characteristics. */

#include "stdpre.h"
#include <stdio.h>

/* We should write the result on stdout, but the original Turbo C 'make' */
/* can't handle output redirection (sigh). */

private void
section(FILE * f, char *str)
{
    fprintf(f, "\n\t /* ---------------- %s ---------------- */\n\n", str);
}

int
main(int argc, char *argv[])
{
    char *fname = argv[1];
    long one = 1;
    char *ffs = "ffffffffffffffff";	/* 8 bytes */
    int ffs_strlen = strlen(ffs);
    struct {
	char c;
	short s;
    } ss;
    struct {
	char c;
	int i;
    } si;
    struct {
	char c;
	long l;
    } sl;
    struct {
	char c;
	char *p;
    } sp;
    struct {
	char c;
	float f;
    } sf;
    struct {
	char c;
	double d;
    } sd;
    static int log2s[17] =
    {0, 0, 1, 0, 2, 0, 0, 0, 3, 0, 0, 0, 0, 0, 0, 0, 4};
    long lm1 = -1;
    long lr1 = lm1 >> 1, lr2 = lm1 >> 2;
    unsigned long um1 = ~(unsigned long)0;
    int im1 = -1;
    int ir1 = im1 >> 1, ir2 = im1 >> 2;
    union {
	long l;
	char *p;
    } pl0, pl1;
    int ars;
    int lwidth = size_of(long) * 8;
    union {
	float f;
	int i;
	long l;
    } f0 , f1, fm1;
    FILE *f = fopen(fname, "w");

    if (f == NULL) {
	fprintf(stderr, "genarch.c: can't open %s for writing\n", fname);
	return exit_FAILED;
    }
    fprintf(f, "/* Parameters derived from machine and compiler architecture */\n");

    section(f, "Scalar alignments");

#define OFFSET_IN(s, e) (int)((char *)&s.e - (char *)&s)
    fprintf(f, "#define arch_align_short_mod %d\n", OFFSET_IN(ss, s));
    fprintf(f, "#define arch_align_int_mod %d\n", OFFSET_IN(si, i));
    fprintf(f, "#define arch_align_long_mod %d\n", OFFSET_IN(sl, l));
    fprintf(f, "#define arch_align_ptr_mod %d\n", OFFSET_IN(sp, p));
    fprintf(f, "#define arch_align_float_mod %d\n", OFFSET_IN(sf, f));
    fprintf(f, "#define arch_align_double_mod %d\n", OFFSET_IN(sd, d));
#undef OFFSET_IN

    section(f, "Scalar sizes");

    fprintf(f, "#define arch_log2_sizeof_short %d\n", log2s[size_of(short)]);
    fprintf(f, "#define arch_log2_sizeof_int %d\n", log2s[size_of(int)]);
    fprintf(f, "#define arch_log2_sizeof_long %d\n", log2s[size_of(long)]);
    fprintf(f, "#define arch_sizeof_ptr %d\n", size_of(char *));
    fprintf(f, "#define arch_sizeof_float %d\n", size_of(float));
    fprintf(f, "#define arch_sizeof_double %d\n", size_of(double));

    section(f, "Unsigned max values");

#define PRINT_MAX(str, typ, tstr, l)\
  fprintf(f, "#define arch_max_%s ((%s)0x%s%s + (%s)0)\n",\
    str, tstr, ffs + ffs_strlen - size_of(typ) * 2, l, tstr)
    PRINT_MAX("uchar", unsigned char, "unsigned char", "");
    PRINT_MAX("ushort", unsigned short, "unsigned short", "");
    PRINT_MAX("uint", unsigned int, "unsigned int", "");
    PRINT_MAX("ulong", unsigned long, "unsigned long", "L");

#undef PRINT_MAX

    section(f, "Miscellaneous");

    fprintf(f, "#define arch_is_big_endian %d\n", 1 - *(char *)&one);
    pl0.l = 0;
    pl1.l = -1;
    fprintf(f, "#define arch_ptrs_are_signed %d\n",
	    (pl1.p < pl0.p));
    f0.f = 0.0, f1.f = 1.0, fm1.f = -1.0;
    /* We have to test the size dynamically here, */
    /* because the preprocessor can't evaluate sizeof. */
    fprintf(f, "#define arch_floats_are_IEEE %d\n",
	    ((size_of(float) == size_of(int) ?
	  f0.i == 0 && f1.i == (int)0x3f800000 && fm1.i == (int)0xbf800000 :
	      f0.l == 0 && f1.l == 0x3f800000L && fm1.l == 0xbf800000L)
	     ? 1 : 0));

    /* There are three cases for arithmetic right shift: */
    /* always correct, correct except for right-shifting a long by 1 */
    /* (a bug in some versions of the Turbo C compiler), and */
    /* never correct. */
    ars = (lr2 != -1 || ir1 != -1 || ir2 != -1 ? 0 :
	   lr1 != -1 ? 1 :	/* Turbo C problem */
	   2);
    fprintf(f, "#define arch_arith_rshift %d\n", ars);
    /* Some machines can't handle a variable shift by */
    /* the full width of a long. */
    fprintf(f, "#define arch_can_shift_full_long %d\n",
	    um1 >> lwidth == 0);

/* ---------------- Done. ---------------- */

    fclose(f);
    return exit_OK;
}
