minix/lib/libc/gdtoa/hdtoa.c
Ben Gras 2fe8fb192f Full switch to clang/ELF. Drop ack. Simplify.
There is important information about booting non-ack images in
docs/UPDATING. ack/aout-format images can't be built any more, and
booting clang/ELF-format ones is a little different. Updating to the
new boot monitor is recommended.

Changes in this commit:

	. drop boot monitor -> allowing dropping ack support
	. facility to copy ELF boot files to /boot so that old boot monitor
	  can still boot fairly easily, see UPDATING
	. no more ack-format libraries -> single-case libraries
	. some cleanup of OBJECT_FMT, COMPILER_TYPE, etc cases
	. drop several ack toolchain commands, but not all support
	  commands (e.g. aal is gone but acksize is not yet).
	. a few libc files moved to netbsd libc dir
	. new /bin/date as minix date used code in libc/
	. test compile fix
	. harmonize includes
	. /usr/lib is no longer special: without ack, /usr/lib plays no
	  kind of special bootstrapping role any more and bootstrapping
	  is done exclusively through packages, so releases depend even
	  less on the state of the machine making them now.
	. rename nbsd_lib* to lib*
	. reduce mtree
2012-02-14 14:52:02 +01:00

363 lines
9.9 KiB
C

/* $NetBSD: hdtoa.c,v 1.6 2008/03/21 23:13:48 christos Exp $ */
/*-
* Copyright (c) 2004, 2005 David Schultz <das@FreeBSD.ORG>
* All rights reserved.
*
* 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.
*
* 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.
*/
#include <sys/cdefs.h>
#if 0
__FBSDID("$FreeBSD: src/lib/libc/gdtoa/_hdtoa.c,v 1.4 2007/01/03 04:57:58 das Exp $");
#else
__RCSID("$NetBSD: hdtoa.c,v 1.6 2008/03/21 23:13:48 christos Exp $");
#endif
#include <float.h>
#include <limits.h>
#include <math.h>
#ifndef __vax__
#include <machine/ieee.h>
#else
#include <machine/vaxfp.h>
#define ieee_double_u vax_dfloating_u
#define dblu_d dfltu_d
#define dblu_dbl dfltu_dflt
#define dbl_sign dflt_sign
#define dbl_exp dflt_exp
#define dbl_frach dflt_frach
#define dbl_fracm dflt_fracm
#define dbl_fracl dflt_fracl
#define DBL_FRACHBITS DFLT_FRACHBITS
#define DBL_FRACMBITS DFLT_FRACMBITS
#define DBL_FRACLBITS DFLT_FRACLBITS
#define DBL_EXPBITS DFLT_EXPBITS
#endif
#include "gdtoaimp.h"
/* Strings values used by dtoa() */
#define INFSTR "Infinity"
#define NANSTR "NaN"
#define DBL_ADJ (DBL_MAX_EXP - 2 + ((DBL_MANT_DIG - 1) % 4))
#define LDBL_ADJ (LDBL_MAX_EXP - 2 + ((LDBL_MANT_DIG - 1) % 4))
/*
* Round up the given digit string. If the digit string is fff...f,
* this procedure sets it to 100...0 and returns 1 to indicate that
* the exponent needs to be bumped. Otherwise, 0 is returned.
*/
static int
roundup(char *s0, int ndigits)
{
char *s;
for (s = s0 + ndigits - 1; *s == 0xf; s--) {
if (s == s0) {
*s = 1;
return (1);
}
*s = 0;
}
++*s;
return (0);
}
/*
* Round the given digit string to ndigits digits according to the
* current rounding mode. Note that this could produce a string whose
* value is not representable in the corresponding floating-point
* type. The exponent pointed to by decpt is adjusted if necessary.
*/
static void
dorounding(char *s0, int ndigits, int sign, int *decpt)
{
int adjust = 0; /* do we need to adjust the exponent? */
switch (FLT_ROUNDS) {
case 0: /* toward zero */
default: /* implementation-defined */
break;
case 1: /* to nearest, halfway rounds to even */
if ((s0[ndigits] > 8) ||
(s0[ndigits] == 8 && s0[ndigits - 1] & 1))
adjust = roundup(s0, ndigits);
break;
case 2: /* toward +inf */
if (sign == 0)
adjust = roundup(s0, ndigits);
break;
case 3: /* toward -inf */
if (sign != 0)
adjust = roundup(s0, ndigits);
break;
}
if (adjust)
*decpt += 4;
}
/*
* This procedure converts a double-precision number in IEEE format
* into a string of hexadecimal digits and an exponent of 2. Its
* behavior is bug-for-bug compatible with dtoa() in mode 2, with the
* following exceptions:
*
* - An ndigits < 0 causes it to use as many digits as necessary to
* represent the number exactly.
* - The additional xdigs argument should point to either the string
* "0123456789ABCDEF" or the string "0123456789abcdef", depending on
* which case is desired.
* - This routine does not repeat dtoa's mistake of setting decpt
* to 9999 in the case of an infinity or NaN. INT_MAX is used
* for this purpose instead.
*
* Note that the C99 standard does not specify what the leading digit
* should be for non-zero numbers. For instance, 0x1.3p3 is the same
* as 0x2.6p2 is the same as 0x4.cp3. This implementation chooses the
* first digit so that subsequent digits are aligned on nibble
* boundaries (before rounding).
*
* Inputs: d, xdigs, ndigits
* Outputs: decpt, sign, rve
*/
char *
hdtoa(double d, const char *xdigs, int ndigits, int *decpt, int *sign,
char **rve)
{
static const int sigfigs = (DBL_MANT_DIG + 3) / 4;
union ieee_double_u u;
char *s, *s0;
size_t bufsize;
u.dblu_d = d;
*sign = u.dblu_dbl.dbl_sign;
switch (fpclassify(d)) {
case FP_NORMAL:
*decpt = u.dblu_dbl.dbl_exp - DBL_ADJ;
break;
case FP_ZERO:
*decpt = 1;
return (nrv_alloc("0", rve, 1));
case FP_SUBNORMAL:
u.dblu_d *= 0x1p514;
*decpt = u.dblu_dbl.dbl_exp - (514 + DBL_ADJ);
break;
case FP_INFINITE:
*decpt = INT_MAX;
return (nrv_alloc(INFSTR, rve, sizeof(INFSTR) - 1));
case FP_NAN:
*decpt = INT_MAX;
return (nrv_alloc(NANSTR, rve, sizeof(NANSTR) - 1));
default:
abort();
}
/* FP_NORMAL or FP_SUBNORMAL */
if (ndigits == 0) /* dtoa() compatibility */
ndigits = 1;
/*
* For simplicity, we generate all the digits even if the
* caller has requested fewer.
*/
bufsize = (sigfigs > ndigits) ? sigfigs : ndigits;
s0 = rv_alloc(bufsize);
if (s0 == NULL)
return NULL;
/*
* We work from right to left, first adding any requested zero
* padding, then the least significant portion of the
* mantissa, followed by the most significant. The buffer is
* filled with the byte values 0x0 through 0xf, which are
* converted to xdigs[0x0] through xdigs[0xf] after the
* rounding phase.
*/
for (s = s0 + bufsize - 1; s > s0 + sigfigs - 1; s--)
*s = 0;
for (; s > s0 + sigfigs - (DBL_FRACLBITS / 4) - 1 && s > s0; s--) {
*s = u.dblu_dbl.dbl_fracl & 0xf;
u.dblu_dbl.dbl_fracl >>= 4;
}
#ifdef DBL_FRACMBITS
for (; s > s0; s--) {
*s = u.dblu_dbl.dbl_fracm & 0xf;
u.dblu_dbl.dbl_fracm >>= 4;
}
#endif
for (; s > s0; s--) {
*s = u.dblu_dbl.dbl_frach & 0xf;
u.dblu_dbl.dbl_frach >>= 4;
}
/*
* At this point, we have snarfed all the bits in the
* mantissa, with the possible exception of the highest-order
* (partial) nibble, which is dealt with by the next
* statement. We also tack on the implicit normalization bit.
*/
*s = u.dblu_dbl.dbl_frach | (1U << ((DBL_MANT_DIG - 1) % 4));
/* If ndigits < 0, we are expected to auto-size the precision. */
if (ndigits < 0) {
for (ndigits = sigfigs; s0[ndigits - 1] == 0; ndigits--)
continue;
}
if (sigfigs > ndigits && s0[ndigits] != 0)
dorounding(s0, ndigits, u.dblu_dbl.dbl_sign, decpt);
s = s0 + ndigits;
if (rve != NULL)
*rve = s;
*s-- = '\0';
for (; s >= s0; s--)
*s = xdigs[(unsigned int)*s];
return (s0);
}
#if (LDBL_MANT_DIG > DBL_MANT_DIG)
/*
* This is the long double version of hdtoa().
*/
char *
hldtoa(long double e, const char *xdigs, int ndigits, int *decpt, int *sign,
char **rve)
{
static const int sigfigs = (LDBL_MANT_DIG + 3) / 4;
union ieee_ext_u u;
char *s, *s0;
size_t bufsize;
u.extu_ld = e;
*sign = u.extu_ext.ext_sign;
switch (fpclassify(e)) {
case FP_NORMAL:
*decpt = u.extu_ext.ext_exp - LDBL_ADJ;
break;
case FP_ZERO:
*decpt = 1;
return (nrv_alloc("0", rve, 1));
case FP_SUBNORMAL:
u.extu_ld *= 0x1p514L;
*decpt = u.extu_ext.ext_exp - (514 + LDBL_ADJ);
break;
case FP_INFINITE:
*decpt = INT_MAX;
return (nrv_alloc(INFSTR, rve, sizeof(INFSTR) - 1));
case FP_NAN:
*decpt = INT_MAX;
return (nrv_alloc(NANSTR, rve, sizeof(NANSTR) - 1));
default:
abort();
}
/* FP_NORMAL or FP_SUBNORMAL */
if (ndigits == 0) /* dtoa() compatibility */
ndigits = 1;
/*
* For simplicity, we generate all the digits even if the
* caller has requested fewer.
*/
bufsize = (sigfigs > ndigits) ? sigfigs : ndigits;
s0 = rv_alloc(bufsize);
if (s0 == NULL)
return NULL;
/*
* We work from right to left, first adding any requested zero
* padding, then the least significant portion of the
* mantissa, followed by the most significant. The buffer is
* filled with the byte values 0x0 through 0xf, which are
* converted to xdigs[0x0] through xdigs[0xf] after the
* rounding phase.
*/
for (s = s0 + bufsize - 1; s > s0 + sigfigs - 1; s--)
*s = 0;
for (; s > s0 + sigfigs - (EXT_FRACLBITS / 4) - 1 && s > s0; s--) {
*s = u.extu_ext.ext_fracl & 0xf;
u.extu_ext.ext_fracl >>= 4;
}
#ifdef EXT_FRACHMBITS
for (; s > s0; s--) {
*s = u.extu_ext.ext_frachm & 0xf;
u.extu_ext.ext_frachm >>= 4;
}
#endif
#ifdef EXT_FRACLMBITS
for (; s > s0; s--) {
*s = u.extu_ext.ext_fraclm & 0xf;
u.extu_ext.ext_fraclm >>= 4;
}
#endif
for (; s > s0; s--) {
*s = u.extu_ext.ext_frach & 0xf;
u.extu_ext.ext_frach >>= 4;
}
/*
* At this point, we have snarfed all the bits in the
* mantissa, with the possible exception of the highest-order
* (partial) nibble, which is dealt with by the next
* statement. We also tack on the implicit normalization bit.
*/
*s = u.extu_ext.ext_frach | (1U << ((LDBL_MANT_DIG - 1) % 4));
/* If ndigits < 0, we are expected to auto-size the precision. */
if (ndigits < 0) {
for (ndigits = sigfigs; s0[ndigits - 1] == 0; ndigits--)
continue;
}
if (sigfigs > ndigits && s0[ndigits] != 0)
dorounding(s0, ndigits, u.extu_ext.ext_sign, decpt);
s = s0 + ndigits;
if (rve != NULL)
*rve = s;
*s-- = '\0';
for (; s >= s0; s--)
*s = xdigs[(unsigned int)*s];
return (s0);
}
#else /* (LDBL_MANT_DIG == DBL_MANT_DIG) */
char *
hldtoa(long double e, const char *xdigs, int ndigits, int *decpt, int *sign,
char **rve)
{
return (hdtoa((double)e, xdigs, ndigits, decpt, sign, rve));
}
#endif /* (LDBL_MANT_DIG == DBL_MANT_DIG) */