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    Length: 2498 (0x9c2)
    Types: TextFile
    Names: »Wsize.c«

└─⟦a0efdde77⟧ Bits:30001252 EUUGD11 Tape, 1987 Spring Conference Helsinki
    └─⟦this⟧ »EUUGD11/gnu-31mar87/scheme/microcode/Wsize.c« 

TextFile

#include <stdio.h>
#include <math.h>
#include <errno.h>

extern int errno;
extern char *malloc();
extern free();

/* Some machines do not set ERANGE by default. */
/* This attempts to fix this. */

#ifdef celerity
#define hack_signal
#endif

#ifdef hack_signal
#define setup_error() signal(SIGFPE, range_error)

range_error()
{ setup_error();
  errno = ERANGE;
}
#else
#define setup_error()
#endif


#define ARR_SIZE 20000
#define MEM_SIZE 400000

/* Force program data to be relatively large. */

static long dummy[ARR_SIZE];

/* Note: comments are printed in a weird way because some
   C compilers eliminate them even from strings.
*/

main()
{ double accum, delta;
  int count, expt_size, char_size, mant_size;
  unsigned long to_be_shifted;
  unsigned bogus;
  char *temp;

  setup_error();
  for(bogus = ((unsigned) -1), count = 0;
      bogus != 0;
      count += 1)
    bogus >>= 1;

  char_size = count/(sizeof(unsigned));
  temp = malloc(MEM_SIZE*sizeof(long));
  if (temp == NULL)
    printf("/%c Cannot allocate %d Pointers. %c/\n",
           '*', MEM_SIZE, '*');
  else count = free(temp);

  if (((unsigned long) temp) < (1 << ((char_size*sizeof(long))-8)))
    printf("#define Heap_In_Low_Memory\n");
  else
    printf("/%c Heap is not in Low Memory. %c/\n", '*', '*');
  	
  to_be_shifted = -1;
  if ((to_be_shifted >> 1) != to_be_shifted)
    printf("#define UNSIGNED_SHIFT\n");
  else
    printf("/%c unsigned longs use arithmetic shifting. %c/\n", 
           '*', '*');

  printf("#define CHAR_SIZE            %d\n",
	 char_size);

  printf("#define USHORT_SIZE          %d\n",
	 (sizeof(unsigned short) * char_size));

  printf("#define ULONG_SIZE           %d\n",
	 (sizeof(unsigned long) * char_size));

  printf("/%c Flonum (double) size is %d bits. %c/\n",
	 '*', (char_size*sizeof(double)), '*');
  
  for(mant_size = 0, accum = 1.0, delta = 0.5;
      ((accum + delta) != accum);
      accum = accum + delta,
      delta /= 2.0,
      mant_size += 1) ;

  for(errno = 0, expt_size = 0, bogus = 1;
      errno != ERANGE;
      expt_size += 1, bogus <<= 1)
    accum = pow(2.0, ((double) bogus));

  expt_size -= 1;

  printf("#define FLONUM_EXPT_SIZE     %d\n", expt_size);
  printf("#define FLONUM_MANTISSA_BITS %d\n", mant_size);
  printf("#define MAX_FLONUM_EXPONENT  %d\n", ((1 << expt_size) - 1));
  printf("/%c Representation %s hidden bit. %c/\n", '*',
	 (((2+expt_size+mant_size) > (char_size*sizeof(double))) ?
	  "uses" :
	  "does not use"), '*');
  return;	
}