Implement __hdtoa() and __hldtoa() and enable printf() support for %a

and %A, which print floating-point numbers in hexadecimal.
This commit is contained in:
David Schultz 2004-01-18 10:32:49 +00:00
parent 6bb87e74a6
commit 8f59277300
3 changed files with 435 additions and 6 deletions

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@ -3,7 +3,7 @@
# netlib gdtoa sources
.PATH: ${.CURDIR}/gdtoa
MISRCS+=_ldtoa.c glue.c
MISRCS+=_hdtoa.c _ldtoa.c glue.c
GDTOASRCS=dmisc.c dtoa.c gdtoa.c gethex.c gmisc.c \
hd_init.c hexnan.c misc.c smisc.c \
strtoIg.c strtod.c strtodg.c strtof.c strtord.c sum.c ulp.c

432
lib/libc/gdtoa/_hdtoa.c Normal file
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@ -0,0 +1,432 @@
/*-
* Copyright (c) 2004 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>
__FBSDID("$FreeBSD$");
#include <float.h>
#include <inttypes.h>
#include <limits.h>
#include <math.h>
#include <stdlib.h>
#include "fpmath.h"
#include "gdtoaimp.h"
/* Strings values used by dtoa() */
#define INFSTR "Infinity"
#define NANSTR "NaN"
#define DBL_BIAS (DBL_MAX_EXP - 1)
#define LDBL_BIAS (LDBL_MAX_EXP - 1)
#ifdef LDBL_IMPLICIT_NBIT
#define LDBL_NBIT_ADJ 0
#else
#define LDBL_NBIT_ADJ 1
#endif
/*
* Efficiently compute the log2 of an integer. Uses a combination of
* arcane tricks found in fortune and arcane tricks not (yet) in
* fortune. This routine behaves similarly to fls(9).
*/
static int
log2_32(uint32_t n)
{
n |= (n >> 1);
n |= (n >> 2);
n |= (n >> 4);
n |= (n >> 8);
n |= (n >> 16);
n = (n & 0x55555555) + ((n & 0xaaaaaaaa) >> 1);
n = (n & 0x33333333) + ((n & 0xcccccccc) >> 2);
n = (n & 0x0f0f0f0f) + ((n & 0xf0f0f0f0) >> 4);
n = (n & 0x00ff00ff) + ((n & 0xff00ff00) >> 8);
n = (n & 0x0000ffff) + ((n & 0xffff0000) >> 16);
return (n - 1);
}
#if (LDBL_MANH_SIZE > 32 || LDBL_MANL_SIZE > 32)
static int
log2_64(uint64_t n)
{
if (n >> 32 != 0)
return (log2_32((uint32_t)(n >> 32)) + 32);
else
return (log2_32((uint32_t)n));
}
#endif /* (LDBL_MANH_SIZE > 32 || LDBL_MANL_SIZE > 32) */
/*
* 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;
}
++*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)
{
union IEEEd2bits u;
char *s, *s0;
int bufsize;
int impnbit; /* implicit normalization bit */
int pos;
int shift; /* for subnormals, # of shifts required to normalize */
int sigfigs; /* number of significant hex figures in result */
u.d = d;
*sign = u.bits.sign;
switch (fpclassify(d)) {
case FP_NORMAL:
sigfigs = (DBL_MANT_DIG + 3) / 4;
impnbit = 1 << ((DBL_MANT_DIG - 1) % 4);
*decpt = u.bits.exp - DBL_BIAS + 1 -
((DBL_MANT_DIG - 1) % 4);
break;
case FP_ZERO:
*decpt = 1;
return (nrv_alloc("0", rve, 1));
case FP_SUBNORMAL:
/*
* The position of the highest-order bit tells us by
* how much to adjust the exponent (decpt). The
* adjustment is raised to the next nibble boundary
* since we will later choose the leftmost hexadecimal
* digit so that all subsequent digits align on nibble
* boundaries.
*/
if (u.bits.manh != 0) {
pos = log2_32(u.bits.manh);
shift = DBL_MANH_SIZE - pos;
} else {
pos = log2_32(u.bits.manl);
shift = DBL_MANH_SIZE + DBL_MANL_SIZE - pos;
}
sigfigs = (3 + DBL_MANT_DIG - shift) / 4;
impnbit = 0;
*decpt = DBL_MIN_EXP - ((shift + 3) & ~(4 - 1));
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);
/*
* 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_MANL_SIZE / 4) - 1 && s > s0; s--) {
*s = u.bits.manl & 0xf;
u.bits.manl >>= 4;
}
for (; s > s0; s--) {
*s = u.bits.manh & 0xf;
u.bits.manh >>= 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. That nibble is usually in manh, but it could be
* in manl instead for small subnormals. We also tack on the
* implicit normalization bit if appropriate.
*/
*s = u.bits.manh | u.bits.manl | impnbit;
/* If ndigits < 0, we are expected to auto-size the precision. */
if (ndigits < 0) {
for (ndigits = sigfigs; s0[ndigits - 1] == 0; ndigits--)
;
}
if (sigfigs > ndigits && s0[ndigits] != 0)
dorounding(s0, ndigits, u.bits.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().
*
* On architectures that have an explicit integer bit, unnormals and
* pseudo-denormals cause problems in the conversion routine, so they
* are ``fixed'' by effectively toggling the integer bit. Although
* this is not correct behavior, the hardware will not produce these
* formats externally.
*/
char *
__hldtoa(long double e, const char *xdigs, int ndigits, int *decpt, int *sign,
char **rve)
{
union IEEEl2bits u;
char *s, *s0;
int bufsize;
int impnbit; /* implicit normalization bit */
int pos;
int shift; /* for subnormals, # of shifts required to normalize */
int sigfigs; /* number of significant hex figures in result */
u.e = e;
*sign = u.bits.sign;
switch (fpclassify(e)) {
case FP_NORMAL:
sigfigs = (LDBL_MANT_DIG + 3) / 4;
impnbit = 1 << ((LDBL_MANT_DIG - 1) % 4);
*decpt = u.bits.exp - LDBL_BIAS + 1 -
((LDBL_MANT_DIG - 1) % 4);
break;
case FP_ZERO:
*decpt = 1;
return (nrv_alloc("0", rve, 1));
case FP_SUBNORMAL:
/*
* The position of the highest-order bit tells us by
* how much to adjust the exponent (decpt). The
* adjustment is raised to the next nibble boundary
* since we will later choose the leftmost hexadecimal
* digit so that all subsequent digits align on nibble
* boundaries.
*/
#ifdef LDBL_IMPLICIT_NBIT
/* Don't trust the normalization bit to be off. */
u.bits.manh &= ~(~0UL << (LDBL_MANH_SIZE - 1));
#endif
if (u.bits.manh != 0) {
#if LDBL_MANH_SIZE > 32
pos = log2_64(u.bits.manh);
#else
pos = log2_32(u.bits.manh);
#endif
shift = LDBL_MANH_SIZE - LDBL_NBIT_ADJ - pos;
} else {
#if LDBL_MANL_SIZE > 32
pos = log2_64(u.bits.manl);
#else
pos = log2_32(u.bits.manl);
#endif
shift = LDBL_MANH_SIZE + LDBL_MANL_SIZE -
LDBL_NBIT_ADJ - pos;
}
sigfigs = (3 + LDBL_MANT_DIG - LDBL_NBIT_ADJ - shift) / 4;
*decpt = LDBL_MIN_EXP + LDBL_NBIT_ADJ -
((shift + 3) & ~(4 - 1));
impnbit = 0;
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);
/*
* 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 - (LDBL_MANL_SIZE / 4) - 1 && s > s0; s--) {
*s = u.bits.manl & 0xf;
u.bits.manl >>= 4;
}
for (; s > s0; s--) {
*s = u.bits.manh & 0xf;
u.bits.manh >>= 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. That nibble is usually in manh, but it could be
* in manl instead for small subnormals. We also tack on the
* implicit normalization bit if appropriate.
*/
*s = u.bits.manh | u.bits.manl | impnbit;
/* If ndigits < 0, we are expected to auto-size the precision. */
if (ndigits < 0) {
for (ndigits = sigfigs; s0[ndigits - 1] == 0; ndigits--)
;
}
if (sigfigs > ndigits && s0[ndigits] != 0)
dorounding(s0, ndigits, u.bits.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) */

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@ -66,8 +66,9 @@ __FBSDID("$FreeBSD$");
#include "local.h"
#include "fvwrite.h"
/* Define FLOATING_POINT to get floating point. */
/* Define FLOATING_POINT to get floating point, HEXFLOAT to get %a. */
#define FLOATING_POINT
#define HEXFLOAT
union arg {
int intarg;
@ -844,10 +845,6 @@ reswitch: switch (ch) {
prec++;
if (dtoaresult != NULL)
freedtoa(dtoaresult);
/*
* XXX We don't actually have a conversion
* XXX routine for this yet.
*/
if (flags & LONGDBL) {
fparg.ldbl = GETARG(long double);
dtoaresult = cp =