/* $NetBSD: ieee754io.c,v 1.6 2024/08/18 20:47:17 christos Exp $ */
/*
* /src/NTP/ntp4-dev/libntp/ieee754io.c,v 4.12 2005/04/16 17:32:10 kardel RELEASE_20050508_A
*
* ieee754io.c,v 4.12 2005/04/16 17:32:10 kardel RELEASE_20050508_A
*
* $Created: Sun Jul 13 09:12:02 1997 $
*
* Copyright (c) 1997-2005 by Frank Kardel <kardel <AT> ntp.org>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the author nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include <stdio.h>
#include "l_stdlib.h"
#include "ntp_stdlib.h"
#include "ntp_fp.h"
#include "ieee754io.h"
static unsigned char get_byte (unsigned char *, offsets_t, int *);
#ifdef __not_yet__
static void put_byte (unsigned char *, offsets_t, int *, unsigned char);
#endif
#ifdef LIBDEBUG
static char *
fmt_blong(
unsigned long val,
int cnt
)
{
char *buf, *s;
int i = cnt;
val <<= 32 - cnt;
LIB_GETBUF(buf);
s = buf;
while (i--)
{
if (val & 0x80000000)
{
*s++ = '1';
}
else
{
*s++ = '0';
}
val <<= 1;
}
*s = '\0';
return buf;
}
static char *
fmt_flt(
unsigned int sign,
unsigned long mh,
unsigned long ml,
unsigned long ch
)
{
char *buf;
LIB_GETBUF(buf);
snprintf(buf, LIB_BUFLENGTH, "%c %s %s %s", sign ? '-' : '+',
fmt_blong(ch, 11),
fmt_blong(mh, 20),
fmt_blong(ml, 32));
return buf;
}
static char *
fmt_hex(
unsigned char *bufp,
int length
)
{
char * buf;
char hex[4];
int i;
LIB_GETBUF(buf);
buf[0] = '\0';
for (i = 0; i < length; i++) {
snprintf(hex, sizeof(hex), "%02x", bufp[i]);
strlcat(buf, hex, LIB_BUFLENGTH);
}
return buf;
}
#endif
static unsigned char
get_byte(
unsigned char *bufp,
offsets_t offset,
int *fieldindex
)
{
unsigned char val;
val = *(bufp + offset[*fieldindex]);
#ifdef LIBDEBUG
if (debug > 4)
printf("fetchieee754: getbyte(0x%08x, %d) = 0x%02x\n", (unsigned int)(bufp)+offset[*fieldindex], *fieldindex, val);
#endif
(*fieldindex)++;
return val;
}
#ifdef __not_yet__
static void
put_byte(
unsigned char *bufp,
offsets_t offsets,
int *fieldindex,
unsigned char val
)
{
*(bufp + offsets[*fieldindex]) = val;
(*fieldindex)++;
}
#endif
/*
* make conversions to and from external IEEE754 formats and internal
* NTP FP format.
*/
int
fetch_ieee754(
unsigned char **buffpp,
int size,
l_fp *lfpp,
offsets_t offsets
)
{
unsigned char *bufp = *buffpp;
unsigned int sign;
unsigned int bias;
unsigned int maxexp;
int mbits;
u_long mantissa_low;
u_long mantissa_high;
u_long characteristic;
long exponent;
#ifdef LIBDEBUG
int length;
#endif
unsigned char val;
int fieldindex = 0;
switch (size)
{
case IEEE_DOUBLE:
#ifdef LIBDEBUG
length = 8;
#endif
mbits = 52;
bias = 1023;
maxexp = 2047;
break;
case IEEE_SINGLE:
#ifdef LIBDEBUG
length = 4;
#endif
mbits = 23;
bias = 127;
maxexp = 255;
break;
default:
return IEEE_BADCALL;
}
val = get_byte(bufp, offsets, &fieldindex); /* fetch sign byte & first part of characteristic */
sign = (val & 0x80) != 0;
characteristic = (val & 0x7F);
val = get_byte(bufp, offsets, &fieldindex); /* fetch rest of characteristic and start of mantissa */
switch (size)
{
case IEEE_SINGLE:
characteristic <<= 1;
characteristic |= (val & 0x80) != 0; /* grab last characteristic bit */
mantissa_high = 0;
mantissa_low = (val &0x7F) << 16;
mantissa_low |= (u_long)get_byte(bufp, offsets, &fieldindex) << 8;
mantissa_low |= get_byte(bufp, offsets, &fieldindex);
break;
case IEEE_DOUBLE:
characteristic <<= 4;
characteristic |= (val & 0xF0) >> 4; /* grab lower characteristic bits */
mantissa_high = (val & 0x0F) << 16;
mantissa_high |= (u_long)get_byte(bufp, offsets, &fieldindex) << 8;
mantissa_high |= get_byte(bufp, offsets, &fieldindex);
mantissa_low = (u_long)get_byte(bufp, offsets, &fieldindex) << 24;
mantissa_low |= (u_long)get_byte(bufp, offsets, &fieldindex) << 16;
mantissa_low |= (u_long)get_byte(bufp, offsets, &fieldindex) << 8;
mantissa_low |= get_byte(bufp, offsets, &fieldindex);
break;
default:
return IEEE_BADCALL;
}
#ifdef LIBDEBUG
if (debug > 4)
{
double d;
float f;
if (size == IEEE_SINGLE)
{
int i;
for (i = 0; i < length; i++)
{
*((unsigned char *)(&f)+i) = *(*buffpp + offsets[i]);
}
d = f;
}
else
{
int i;
for (i = 0; i < length; i++)
{
*((unsigned char *)(&d)+i) = *(*buffpp + offsets[i]);
}
}
printf("fetchieee754: FP: %s -> %s -> %e(=%s)\n", fmt_hex(*buffpp, length),
fmt_flt(sign, mantissa_high, mantissa_low, characteristic),
d, fmt_hex((unsigned char *)&d, length));
}
#endif
*buffpp += fieldindex;
/*
* detect funny numbers
*/
if (characteristic == maxexp)
{
/*
* NaN or Infinity
*/
if (mantissa_low || mantissa_high)
{
/*
* NaN
*/
return IEEE_NAN;
}
else
{
/*
* +Inf or -Inf
*/
return sign ? IEEE_NEGINFINITY : IEEE_POSINFINITY;
}
}
else
{
/*
* collect real numbers
*/
L_CLR(lfpp);
/*
* check for overflows
*/
exponent = characteristic - bias;
if (exponent > 31) /* sorry - hardcoded */
{
/*
* overflow only in respect to NTP-FP representation
*/
return sign ? IEEE_NEGOVERFLOW : IEEE_POSOVERFLOW;
}
else
{
int frac_offset; /* where the fraction starts */
frac_offset = mbits - exponent;
if (characteristic == 0)
{
/*
* de-normalized or tiny number - fits only as 0
*/
return IEEE_OK;
}
else
{
/*
* adjust for implied 1
*/
if (mbits > 31)
mantissa_high |= 1 << (mbits - 32);
else
mantissa_low |= 1 << mbits;
/*
* take mantissa apart - if only all machine would support
* 64 bit operations 8-(
*/
if (frac_offset > mbits)
{
lfpp->l_ui = 0; /* only fractional number */
frac_offset -= mbits + 1; /* will now contain right shift count - 1*/
if (mbits > 31)
{
lfpp->l_uf = mantissa_high << (63 - mbits);
lfpp->l_uf |= mantissa_low >> (mbits - 33);
lfpp->l_uf >>= frac_offset;
}
else
{
lfpp->l_uf = mantissa_low >> frac_offset;
}
}
else
{
if (frac_offset > 32)
{
/*
* must split in high word
*/
lfpp->l_ui = mantissa_high >> (frac_offset - 32);
lfpp->l_uf = (mantissa_high & ((1 << (frac_offset - 32)) - 1)) << (64 - frac_offset);
lfpp->l_uf |= mantissa_low >> (frac_offset - 32);
}
else
{
/*
* must split in low word
*/
lfpp->l_ui = mantissa_high << (32 - frac_offset);
lfpp->l_ui |= (mantissa_low >> frac_offset) & ((1 << (32 - frac_offset)) - 1);
lfpp->l_uf = (mantissa_low & ((1 << frac_offset) - 1)) << (32 - frac_offset);
}
}
/*
* adjust for sign
*/
if (sign)
{
L_NEG(lfpp);
}
return IEEE_OK;
}
}
}
}
/*
* DLH: This function is currently unused in ntpd. If you think about
* using it, be sure it does what you intend. I notice the bufpp arg
* is never referenced, and the calculated mantissa_high & mantissa_low
* are only referenced in debug output. It seems they're supposed to
* be composed into an ieee754-format float and stored at *bufpp or
* possibly **bufpp. Brought to my attention by this:
*
* ieee754io.c:414:10: warning: variable 'mantissa_low' set but not used
* [-Wunused-but-set-variable]
*
* To quiet it I'm #ifdef'ing the function away for now, here and below
* the call to it in main().
*/
#ifdef PUT_IEEE754_UNUSED_FUNC
int
put_ieee754(
unsigned char **bufpp,
int size,
l_fp *lfpp,
offsets_t offsets
)
{
l_fp outlfp;
#ifdef LIBDEBUG
unsigned int sign;
unsigned int bias;
#endif
/*unsigned int maxexp;*/
int mbits;
int msb;
u_long mantissa_low = 0;
u_long mantissa_high = 0;
#ifdef LIBDEBUG
u_long characteristic = 0;
long exponent;
#endif
/*int length;*/
unsigned long mask;
outlfp = *lfpp;
switch (size)
{
case IEEE_DOUBLE:
/*length = 8;*/
mbits = 52;
#ifdef LIBDEBUG
bias = 1023;
#endif
/*maxexp = 2047;*/
break;
case IEEE_SINGLE:
/*length = 4;*/
mbits = 23;
#ifdef LIBDEBUG
bias = 127;
#endif
/*maxexp = 255;*/
break;
default:
return IEEE_BADCALL;
}
/*
* find sign
*/
if (L_ISNEG(&outlfp))
{
L_NEG(&outlfp);
#ifdef LIBDEBUG
sign = 1;
#endif
}
else
{
#ifdef LIBDEBUG
sign = 0;
#endif
}
if (L_ISZERO(&outlfp))
{
#ifdef LIBDEBUG
exponent = mantissa_high = mantissa_low = 0; /* true zero */
#endif
}
else
{
/*
* find number of significant integer bits
*/
mask = 0x80000000;
if (outlfp.l_ui)
{
msb = 63;
while (mask && ((outlfp.l_ui & mask) == 0))
{
mask >>= 1;
msb--;
}
}
else
{
msb = 31;
while (mask && ((outlfp.l_uf & mask) == 0))
{
mask >>= 1;
msb--;
}
}
switch (size)
{
case IEEE_SINGLE:
mantissa_high = 0;
if (msb >= 32)
{
mantissa_low = (outlfp.l_ui & ((1 << (msb - 32)) - 1)) << (mbits - (msb - 32));
mantissa_low |= outlfp.l_uf >> (mbits - (msb - 32));
}
else
{
mantissa_low = (outlfp.l_uf << (mbits - msb)) & ((1 << mbits) - 1);
}
break;
case IEEE_DOUBLE:
if (msb >= 32)
{
mantissa_high = (outlfp.l_ui << (mbits - msb)) & ((1 << (mbits - 32)) - 1);
mantissa_high |= outlfp.l_uf >> (32 - (mbits - msb));
mantissa_low = (outlfp.l_ui & ((1 << (msb - mbits)) - 1)) << (32 - (msb - mbits));
mantissa_low |= outlfp.l_uf >> (msb - mbits);
}
else
{
mantissa_high = outlfp.l_uf << (mbits - 32 - msb);
mantissa_low = outlfp.l_uf << (mbits - 32);
}
}
#ifdef LIBDEBUG
exponent = msb - 32;
characteristic = exponent + bias;
if (debug > 4)
printf("FP: %s\n", fmt_flt(sign, mantissa_high, mantissa_low, characteristic));
#endif
}
return IEEE_OK;
}
#endif /* PUT_IEEE754_UNUSED_FUNC */
#if defined(DEBUG) && defined(LIBDEBUG)
int main(
int argc,
char **argv
)
{
static offsets_t native_off = { 0, 1, 2, 3, 4, 5, 6, 7 };
double f = 1.0;
double *f_p = &f;
l_fp fp;
if (argc == 2)
{
if (sscanf(argv[1], "%lf", &f) != 1)
{
printf("cannot convert %s to a float\n", argv[1]);
return 1;
}
}
printf("double: %s %s\n", fmt_blong(*(unsigned long *)&f, 32), fmt_blong(*(unsigned long *)((char *)(&f)+4), 32));
printf("fetch from %f = %d\n", f, fetch_ieee754((void *)&f_p, IEEE_DOUBLE, &fp, native_off));
printf("fp [%s %s] = %s\n", fmt_blong(fp.l_ui, 32), fmt_blong(fp.l_uf, 32), mfptoa(fp.l_ui, fp.l_uf, 15));
f_p = &f;
#ifdef PUT_IEEE754_UNUSED_FUNC
put_ieee754((void *)&f_p, IEEE_DOUBLE, &fp, native_off);
/* there should be a check on *f_p (f) having the expected result here */
#endif /* PUT_IEEE754_UNUSED_FUNC */
return 0;
}
#endif
/*
* History:
*
* ieee754io.c,v
* Revision 4.12 2005/04/16 17:32:10 kardel
* update copyright
*
* Revision 4.11 2004/11/14 15:29:41 kardel
* support PPSAPI, upgrade Copyright to Berkeley style
*
* Revision 4.8 1999/02/21 12:17:36 kardel
* 4.91f reconcilation
*
* Revision 4.7 1999/02/21 11:26:03 kardel
* renamed index to fieldindex to avoid index() name clash
*
* Revision 4.6 1998/11/15 20:27:52 kardel
* Release 4.0.73e13 reconcilation
*
* Revision 4.5 1998/08/16 19:01:51 kardel
* debug information only compile for LIBDEBUG case
*
* Revision 4.4 1998/08/09 09:39:28 kardel
* Release 4.0.73e2 reconcilation
*
* Revision 4.3 1998/06/13 11:56:19 kardel
* disabled putbute() for the time being
*
* Revision 4.2 1998/06/12 15:16:58 kardel
* ansi2knr compatibility
*
* Revision 4.1 1998/05/24 07:59:56 kardel
* conditional debug support
*
* Revision 4.0 1998/04/10 19:46:29 kardel
* Start 4.0 release version numbering
*
* Revision 1.1 1998/04/10 19:27:46 kardel
* initial NTP VERSION 4 integration of PARSE with GPS166 binary support
*
* Revision 1.1 1997/10/06 21:05:45 kardel
* new parse structure
*
*/
