14bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes/* $OpenBSD: hdtoa.c,v 1.2 2009/10/16 12:15:03 martynas Exp $ */ 24bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes/*- 34bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes * Copyright (c) 2004, 2005 David Schultz <das@FreeBSD.ORG> 44bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes * All rights reserved. 54bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes * 64bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes * Redistribution and use in source and binary forms, with or without 74bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes * modification, are permitted provided that the following conditions 84bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes * are met: 94bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes * 1. Redistributions of source code must retain the above copyright 104bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes * notice, this list of conditions and the following disclaimer. 114bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes * 2. Redistributions in binary form must reproduce the above copyright 124bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes * notice, this list of conditions and the following disclaimer in the 134bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes * documentation and/or other materials provided with the distribution. 144bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes * 154bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 164bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 174bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 184bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 194bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 204bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 214bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 224bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 234bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 244bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 254bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes * SUCH DAMAGE. 264bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes */ 274bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes 284bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes#include <sys/types.h> 294bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes#include <machine/ieee.h> 304bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes#include <float.h> 314bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes#include <limits.h> 324bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes#include <math.h> 334bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes 344bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes#include "gdtoaimp.h" 354bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes 364bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes/* Strings values used by dtoa() */ 374bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes#define INFSTR "Infinity" 384bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes#define NANSTR "NaN" 394bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes 404bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes#define DBL_ADJ (DBL_MAX_EXP - 2 + ((DBL_MANT_DIG - 1) % 4)) 414bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes#define LDBL_ADJ (LDBL_MAX_EXP - 2 + ((LDBL_MANT_DIG - 1) % 4)) 424bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes 434bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes/* 444bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes * Round up the given digit string. If the digit string is fff...f, 454bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes * this procedure sets it to 100...0 and returns 1 to indicate that 464bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes * the exponent needs to be bumped. Otherwise, 0 is returned. 474bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes */ 484bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughesstatic int 494bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughesroundup(char *s0, int ndigits) 504bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes{ 514bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes char *s; 524bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes 534bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes for (s = s0 + ndigits - 1; *s == 0xf; s--) { 544bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes if (s == s0) { 554bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes *s = 1; 564bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes return (1); 574bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes } 584bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes *s = 0; 594bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes } 604bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes ++*s; 614bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes return (0); 624bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes} 634bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes 644bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes/* 654bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes * Round the given digit string to ndigits digits according to the 664bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes * current rounding mode. Note that this could produce a string whose 674bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes * value is not representable in the corresponding floating-point 684bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes * type. The exponent pointed to by decpt is adjusted if necessary. 694bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes */ 704bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughesstatic void 714bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughesdorounding(char *s0, int ndigits, int sign, int *decpt) 724bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes{ 734bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes int adjust = 0; /* do we need to adjust the exponent? */ 744bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes 754bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes switch (FLT_ROUNDS) { 764bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes case 0: /* toward zero */ 774bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes default: /* implementation-defined */ 784bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes break; 794bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes case 1: /* to nearest, halfway rounds to even */ 804bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes if ((s0[ndigits] > 8) || 814bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes (s0[ndigits] == 8 && s0[ndigits + 1] & 1)) 824bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes adjust = roundup(s0, ndigits); 834bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes break; 844bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes case 2: /* toward +inf */ 854bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes if (sign == 0) 864bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes adjust = roundup(s0, ndigits); 874bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes break; 884bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes case 3: /* toward -inf */ 894bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes if (sign != 0) 904bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes adjust = roundup(s0, ndigits); 914bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes break; 924bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes } 934bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes 944bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes if (adjust) 954bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes *decpt += 4; 964bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes} 974bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes 984bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes/* 994bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes * This procedure converts a double-precision number in IEEE format 1004bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes * into a string of hexadecimal digits and an exponent of 2. Its 1014bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes * behavior is bug-for-bug compatible with dtoa() in mode 2, with the 1024bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes * following exceptions: 1034bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes * 1044bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes * - An ndigits < 0 causes it to use as many digits as necessary to 1054bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes * represent the number exactly. 1064bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes * - The additional xdigs argument should point to either the string 1074bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes * "0123456789ABCDEF" or the string "0123456789abcdef", depending on 1084bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes * which case is desired. 1094bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes * - This routine does not repeat dtoa's mistake of setting decpt 1104bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes * to 9999 in the case of an infinity or NaN. INT_MAX is used 1114bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes * for this purpose instead. 1124bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes * 1134bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes * Note that the C99 standard does not specify what the leading digit 1144bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes * should be for non-zero numbers. For instance, 0x1.3p3 is the same 1154bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes * as 0x2.6p2 is the same as 0x4.cp3. This implementation chooses the 1164bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes * first digit so that subsequent digits are aligned on nibble 1174bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes * boundaries (before rounding). 1184bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes * 1194bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes * Inputs: d, xdigs, ndigits 1204bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes * Outputs: decpt, sign, rve 1214bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes */ 1224bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hugheschar * 1234bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes__hdtoa(double d, const char *xdigs, int ndigits, int *decpt, int *sign, 1244bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes char **rve) 1254bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes{ 1264bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes static const int sigfigs = (DBL_MANT_DIG + 3) / 4; 1274bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes struct ieee_double *p = (struct ieee_double *)&d; 1284bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes char *s, *s0; 1294bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes int bufsize; 1304bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes 1314bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes *sign = p->dbl_sign; 1324bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes 1334bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes switch (fpclassify(d)) { 1344bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes case FP_NORMAL: 1354bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes *decpt = p->dbl_exp - DBL_ADJ; 1364bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes break; 1374bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes case FP_ZERO: 1384bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes *decpt = 1; 1394bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes return (nrv_alloc("0", rve, 1)); 1404bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes case FP_SUBNORMAL: 1414bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes d *= 0x1p514; 1424bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes *decpt = p->dbl_exp - (514 + DBL_ADJ); 1434bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes break; 1444bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes case FP_INFINITE: 1454bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes *decpt = INT_MAX; 1464bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes return (nrv_alloc(INFSTR, rve, sizeof(INFSTR) - 1)); 1474bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes case FP_NAN: 1484bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes *decpt = INT_MAX; 1494bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes return (nrv_alloc(NANSTR, rve, sizeof(NANSTR) - 1)); 1504bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes default: 1514bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes abort(); 1524bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes } 1534bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes 1544bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes /* FP_NORMAL or FP_SUBNORMAL */ 1554bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes 1564bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes if (ndigits == 0) /* dtoa() compatibility */ 1574bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes ndigits = 1; 1584bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes 1594bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes /* 1604bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes * For simplicity, we generate all the digits even if the 1614bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes * caller has requested fewer. 1624bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes */ 1634bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes bufsize = (sigfigs > ndigits) ? sigfigs : ndigits; 1644bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes s0 = rv_alloc(bufsize); 1654bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes if (s0 == NULL) 1664bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes return (NULL); 1674bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes 1684bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes /* 1694bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes * We work from right to left, first adding any requested zero 1704bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes * padding, then the least significant portion of the 1714bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes * mantissa, followed by the most significant. The buffer is 1724bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes * filled with the byte values 0x0 through 0xf, which are 1734bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes * converted to xdigs[0x0] through xdigs[0xf] after the 1744bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes * rounding phase. 1754bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes */ 1764bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes for (s = s0 + bufsize - 1; s > s0 + sigfigs - 1; s--) 1774bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes *s = 0; 1784bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes for (; s > s0 + sigfigs - (DBL_FRACLBITS / 4) - 1 && s > s0; s--) { 1794bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes *s = p->dbl_fracl & 0xf; 1804bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes p->dbl_fracl >>= 4; 1814bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes } 1824bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes for (; s > s0; s--) { 1834bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes *s = p->dbl_frach & 0xf; 1844bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes p->dbl_frach >>= 4; 1854bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes } 1864bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes 1874bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes /* 1884bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes * At this point, we have snarfed all the bits in the 1894bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes * mantissa, with the possible exception of the highest-order 1904bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes * (partial) nibble, which is dealt with by the next 1914bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes * statement. We also tack on the implicit normalization bit. 1924bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes */ 1934bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes *s = p->dbl_frach | (1U << ((DBL_MANT_DIG - 1) % 4)); 1944bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes 1954bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes /* If ndigits < 0, we are expected to auto-size the precision. */ 1964bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes if (ndigits < 0) { 1974bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes for (ndigits = sigfigs; s0[ndigits - 1] == 0; ndigits--) 1984bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes ; 1994bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes } 2004bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes 2014bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes if (sigfigs > ndigits && s0[ndigits] != 0) 2024bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes dorounding(s0, ndigits, p->dbl_sign, decpt); 2034bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes 2044bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes s = s0 + ndigits; 2054bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes if (rve != NULL) 2064bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes *rve = s; 2074bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes *s-- = '\0'; 2084bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes for (; s >= s0; s--) 2094bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes *s = xdigs[(unsigned int)*s]; 2104bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes 2114bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes return (s0); 2124bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes} 2134bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes 2144bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes#if (LDBL_MANT_DIG > DBL_MANT_DIG) 2154bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes 2164bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes/* 2174bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes * This is the long double version of __hdtoa(). 2184bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes */ 2194bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hugheschar * 2204bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes__hldtoa(long double e, const char *xdigs, int ndigits, int *decpt, int *sign, 2214bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes char **rve) 2224bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes{ 2234bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes static const int sigfigs = (LDBL_MANT_DIG + 3) / 4; 2244bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes struct ieee_ext *p = (struct ieee_ext *)&e; 2254bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes char *s, *s0; 2264bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes int bufsize; 2274bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes 2284bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes *sign = p->ext_sign; 2294bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes 2304bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes switch (fpclassify(e)) { 2314bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes case FP_NORMAL: 2324bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes *decpt = p->ext_exp - LDBL_ADJ; 2334bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes break; 2344bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes case FP_ZERO: 2354bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes *decpt = 1; 2364bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes return (nrv_alloc("0", rve, 1)); 2374bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes case FP_SUBNORMAL: 2384bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes e *= 0x1p514L; 2394bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes *decpt = p->ext_exp - (514 + LDBL_ADJ); 2404bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes break; 2414bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes case FP_INFINITE: 2424bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes *decpt = INT_MAX; 2434bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes return (nrv_alloc(INFSTR, rve, sizeof(INFSTR) - 1)); 2444bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes case FP_NAN: 2454bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes *decpt = INT_MAX; 2464bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes return (nrv_alloc(NANSTR, rve, sizeof(NANSTR) - 1)); 2474bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes default: 2484bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes abort(); 2494bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes } 2504bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes 2514bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes /* FP_NORMAL or FP_SUBNORMAL */ 2524bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes 2534bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes if (ndigits == 0) /* dtoa() compatibility */ 2544bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes ndigits = 1; 2554bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes 2564bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes /* 2574bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes * For simplicity, we generate all the digits even if the 2584bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes * caller has requested fewer. 2594bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes */ 2604bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes bufsize = (sigfigs > ndigits) ? sigfigs : ndigits; 2614bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes s0 = rv_alloc(bufsize); 2624bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes if (s0 == NULL) 2634bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes return (NULL); 2644bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes 2654bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes /* 2664bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes * We work from right to left, first adding any requested zero 2674bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes * padding, then the least significant portion of the 2684bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes * mantissa, followed by the most significant. The buffer is 2694bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes * filled with the byte values 0x0 through 0xf, which are 2704bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes * converted to xdigs[0x0] through xdigs[0xf] after the 2714bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes * rounding phase. 2724bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes */ 2734bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes for (s = s0 + bufsize - 1; s > s0 + sigfigs - 1; s--) 2744bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes *s = 0; 2754bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes for (; s > s0 + sigfigs - (EXT_FRACLBITS / 4) - 1 && s > s0; s--) { 2764bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes *s = p->ext_fracl & 0xf; 2774bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes p->ext_fracl >>= 4; 2784bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes } 2794bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes#ifdef EXT_FRACHMBITS 2804bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes for (; s > s0; s--) { 2814bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes *s = p->ext_frachm & 0xf; 2824bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes p->ext_frachm >>= 4; 2834bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes } 2844bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes#endif 2854bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes#ifdef EXT_FRACLMBITS 2864bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes for (; s > s0; s--) { 2874bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes *s = p->ext_fraclm & 0xf; 2884bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes p->ext_fraclm >>= 4; 2894bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes } 2904bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes#endif 2914bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes for (; s > s0; s--) { 2924bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes *s = p->ext_frach & 0xf; 2934bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes p->ext_frach >>= 4; 2944bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes } 2954bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes 2964bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes /* 2974bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes * At this point, we have snarfed all the bits in the 2984bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes * mantissa, with the possible exception of the highest-order 2994bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes * (partial) nibble, which is dealt with by the next 3004bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes * statement. We also tack on the implicit normalization bit. 3014bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes */ 3024bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes *s = p->ext_frach | (1U << ((LDBL_MANT_DIG - 1) % 4)); 3034bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes 3044bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes /* If ndigits < 0, we are expected to auto-size the precision. */ 3054bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes if (ndigits < 0) { 3064bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes for (ndigits = sigfigs; s0[ndigits - 1] == 0; ndigits--) 3074bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes ; 3084bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes } 3094bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes 3104bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes if (sigfigs > ndigits && s0[ndigits] != 0) 3114bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes dorounding(s0, ndigits, p->ext_sign, decpt); 3124bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes 3134bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes s = s0 + ndigits; 3144bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes if (rve != NULL) 3154bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes *rve = s; 3164bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes *s-- = '\0'; 3174bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes for (; s >= s0; s--) 3184bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes *s = xdigs[(unsigned int)*s]; 3194bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes 3204bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes return (s0); 3214bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes} 3224bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes 3234bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes#else /* (LDBL_MANT_DIG == DBL_MANT_DIG) */ 3244bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes 3254bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hugheschar * 3264bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes__hldtoa(long double e, const char *xdigs, int ndigits, int *decpt, int *sign, 3274bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes char **rve) 3284bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes{ 3294bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes return (__hdtoa((double)e, xdigs, ndigits, decpt, sign, rve)); 3304bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes} 3314bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes 3324bd97cee28dd815fff54fc97560be60d566c1fa5Elliott Hughes#endif /* (LDBL_MANT_DIG == DBL_MANT_DIG) */ 333