simulacion-permeabilidad/tools/connec/libf2c/arithchk.c

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Copyright (C) 1997, 1998, 2000 Lucent Technologies
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LUCENT DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS.
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IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION,
ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF
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****************************************************************/

/* Try to deduce arith.h from arithmetic properties. */

#include <stdio.h>
#include <string.h>	/* possibly for ssize_t */
#include <math.h>
#include <errno.h>
#include <sys/types.h>	/* another possible place for ssize_t */

#ifdef NO_FPINIT
#define fpinit_ASL()
#else
#ifndef KR_headers
extern
#ifdef __cplusplus
	"C"
#endif
	void fpinit_ASL(void);
#endif /*KR_headers*/
#endif /*NO_FPINIT*/

 static int dalign;
 typedef struct
Akind {
	char *name;
	int   kind;
	} Akind;

 static Akind
IEEE_8087	= { "IEEE_8087", 1 },
IEEE_MC68k	= { "IEEE_MC68k", 2 },
IBM		= { "IBM", 3 },
VAX		= { "VAX", 4 },
CRAY		= { "CRAY", 5};

 static double t_nan;

 static Akind *
Lcheck(void)
{
	union {
		double d;
		long L[2];
		} u;
	struct {
		double d;
		long L;
		} x[2];

	if (sizeof(x) > 2*(sizeof(double) + sizeof(long)))
		dalign = 1;
	u.L[0] = u.L[1] = 0;
	u.d = 1e13;
	if (u.L[0] == 1117925532 && u.L[1] == -448790528)
		return &IEEE_MC68k;
	if (u.L[1] == 1117925532 && u.L[0] == -448790528)
		return &IEEE_8087;
	if (u.L[0] == -2065213935 && u.L[1] == 10752)
		return &VAX;
	if (u.L[0] == 1267827943 && u.L[1] == 704643072)
		return &IBM;
	return 0;
	}

 static Akind *
icheck(void)
{
	union {
		double d;
		int L[2];
		} u;
	struct {
		double d;
		int L;
		} x[2];

	if (sizeof(x) > 2*(sizeof(double) + sizeof(int)))
		dalign = 1;
	u.L[0] = u.L[1] = 0;
	u.d = 1e13;
	if (u.L[0] == 1117925532 && u.L[1] == -448790528)
		return &IEEE_MC68k;
	if (u.L[1] == 1117925532 && u.L[0] == -448790528)
		return &IEEE_8087;
	if (u.L[0] == -2065213935 && u.L[1] == 10752)
		return &VAX;
	if (u.L[0] == 1267827943 && u.L[1] == 704643072)
		return &IBM;
	return 0;
	}

char *emptyfmt = "";	/* avoid possible warning message with printf("") */

 static Akind *
ccheck(void)
{
	union {
		double d;
		long L;
		} u;
	long Cray1;

	/* Cray1 = 4617762693716115456 -- without overflow on non-Crays */
	Cray1 = printf(emptyfmt) < 0 ? 0 : 4617762;
	if (printf(emptyfmt, Cray1) >= 0)
		Cray1 = 1000000*Cray1 + 693716;
	if (printf(emptyfmt, Cray1) >= 0)
		Cray1 = 1000000*Cray1 + 115456;
	u.d = 1e13;
	if (u.L == Cray1)
		return &CRAY;
	return 0;
	}

 static int
fzcheck(void)
{
	double a, b;
	int i;

	a = 1.;
	b = .1;
	for(i = 155;; b *= b, i >>= 1) {
		if (i & 1) {
			a *= b;
			if (i == 1)
				break;
			}
		}
	b = a * a;
	return b == 0.;
	}

 static int
need_nancheck(void)
{
	double t;

	errno = 0;
	t = log(t_nan);
	if (errno == 0)
		return 1;
	errno = 0;
	t = sqrt(t_nan);
	return errno == 0;
	}

 void
get_nanbits(unsigned int *b, int k)
{
	union { double d; unsigned int z[2]; } u, u1, u2;

	k = 2 - k;
	u1.z[k] = u2.z[k] = 0x7ff00000;
	u1.z[1-k] = u2.z[1-k] = 0;
	u.d = u1.d - u2.d;	/* Infinity - Infinity */
	b[0] = u.z[0];
	b[1] = u.z[1];
	}

 int
main(void)
{
	FILE *f;
	Akind *a = 0;
	int Ldef = 0;
	size_t sa, sb;
	unsigned int nanbits[2];

	fpinit_ASL();
#ifdef WRITE_ARITH_H	/* for Symantec's buggy "make" */
	f = fopen("arith.h", "w");
	if (!f) {
		printf("Cannot open arith.h\n");
		return 1;
		}
#else
	f = stdout;
#endif

	if (sizeof(double) == 2*sizeof(long))
		a = Lcheck();
	else if (sizeof(double) == 2*sizeof(int)) {
		Ldef = 1;
		a = icheck();
		}
	else if (sizeof(double) == sizeof(long))
		a = ccheck();
	if (a) {
		fprintf(f, "#define %s\n#define Arith_Kind_ASL %d\n",
			a->name, a->kind);
		if (Ldef)
			fprintf(f, "#define Long int\n#define Intcast (int)(long)\n");
		if (dalign)
			fprintf(f, "#define Double_Align\n");
		if (sizeof(char*) == 8)
			fprintf(f, "#define X64_bit_pointers\n");
#ifndef NO_LONG_LONG
		if (sizeof(long long) > sizeof(long)
		 && sizeof(long long) == sizeof(void*))
			fprintf(f, "#define LONG_LONG_POINTERS\n");
		if (sizeof(long long) < 8)
#endif
			fprintf(f, "#define NO_LONG_LONG\n");
#ifdef NO_SSIZE_T /*{{*/
		if (sizeof(size_t) == sizeof(long))
			fprintf(f, "#define ssize_t long\n");
		else if (sizeof(size_t) == sizeof(int))
			fprintf(f, "#define ssize_t int\n");
#ifndef NO_LONG_LONG
		else if (sizeof(size_t) == sizeof(long long))
			fprintf(f, "#define ssize_t long long\n");
#endif
		else
			fprintf(f, "#define ssize_t signed size_t\n"); /* punt */
#else /*}{*/
		if (sizeof(size_t) != sizeof(ssize_t))
			fprintf(f, "/* sizeof(size_t) = %d but sizeof(ssize_t) = %d */\n",
				(int)sizeof(size_t), (int)sizeof(ssize_t));
#endif /*}}*/
		if (a->kind <= 2) {
			if (fzcheck())
				fprintf(f, "#define Sudden_Underflow\n");
			t_nan = -a->kind;
			if (need_nancheck())
				fprintf(f, "#define NANCHECK\n");
			if (sizeof(double) == 2*sizeof(unsigned int)) {
				get_nanbits(nanbits, a->kind);
				fprintf(f, "#define QNaN0 0x%x\n", nanbits[0]);
				fprintf(f, "#define QNaN1 0x%x\n", nanbits[1]);
				}
			}
		return 0;
		}
	fprintf(f, "/* Unknown arithmetic */\n");
	return 1;
	}

#ifdef __sun
#ifdef __i386
/* kludge for Intel Solaris */
void fpsetprec(int x) { }
#endif
#endif