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

and %A, which print floating-point numbers in hexadecimal.

3 files changed, 435 insertions, 6 deletions

diff --git a/lib/libc/gdtoa/Makefile.inc b/lib/libc/gdtoa/Makefile.inc
index 2622a81..2190636 100644
--- a/lib/libc/gdtoa/Makefile.inc
+++ b/lib/libc/gdtoa/Makefile.inc
@@ -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
diff --git a/lib/libc/gdtoa/_hdtoa.c b/lib/libc/gdtoa/_hdtoa.c
new file mode 100644
index 0000000..1bfdb84
--- /dev/null
+++ b/lib/libc/gdtoa/_hdtoa.c
@@ -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) */
diff --git a/lib/libc/stdio/vfprintf.c b/lib/libc/stdio/vfprintf.c
index 8d048a3..138aa22 100644
--- a/lib/libc/stdio/vfprintf.c
+++ b/lib/libc/stdio/vfprintf.c
@@ -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 =