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Diffstat (limited to 'lib/libc/gdtoa/_hldtoa.c')
-rw-r--r-- | lib/libc/gdtoa/_hldtoa.c | 177 |
1 files changed, 177 insertions, 0 deletions
diff --git a/lib/libc/gdtoa/_hldtoa.c b/lib/libc/gdtoa/_hldtoa.c new file mode 100644 index 0000000..97394ea --- /dev/null +++ b/lib/libc/gdtoa/_hldtoa.c @@ -0,0 +1,177 @@ +/*- + * Copyright (c) 2004-2008 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 <limits.h> +#include <math.h> +#include <stdint.h> + +#ifdef __i386__ +#include <ieeefp.h> +#endif + +#include "../stdio/floatio.h" +#include "fpmath.h" +#include "gdtoaimp.h" + +#if (LDBL_MANT_DIG > DBL_MANT_DIG) + +/* Strings values used by dtoa() */ +#define INFSTR "Infinity" +#define NANSTR "NaN" + +#ifdef LDBL_IMPLICIT_NBIT +#define MANH_SIZE LDBL_MANH_SIZE +#else +#define MANH_SIZE (LDBL_MANH_SIZE - 1) +#endif + +#if MANH_SIZE > 32 +typedef uint64_t manh_t; +#else +typedef uint32_t manh_t; +#endif + +#if LDBL_MANL_SIZE > 32 +typedef uint64_t manl_t; +#else +typedef uint32_t manl_t; +#endif + +#define LDBL_ADJ (LDBL_MAX_EXP - 2) +#define SIGFIGS ((LDBL_MANT_DIG + 3) / 4 + 1) + +static const float one[] = { 1.0f, -1.0f }; + +/* + * This is the long double version of __hdtoa(). + */ +char * +__hldtoa(long double e, const char *xdigs, int ndigits, int *decpt, int *sign, + char **rve) +{ + union IEEEl2bits u; + char *s, *s0; + manh_t manh; + manl_t manl; + int bufsize; +#ifdef __i386__ + fp_prec_t oldprec; +#endif + + u.e = e; + *sign = u.bits.sign; + + switch (fpclassify(e)) { + case FP_NORMAL: + *decpt = u.bits.exp - LDBL_ADJ; + break; + case FP_ZERO: + *decpt = 1; + return (nrv_alloc("0", rve, 1)); + case FP_SUBNORMAL: +#ifdef __i386__ + oldprec = fpsetprec(FP_PE); +#endif + u.e *= 0x1p514L; + *decpt = u.bits.exp - (514 + LDBL_ADJ); +#ifdef __i386__ + fpsetprec(oldprec); +#endif + break; + case FP_INFINITE: + *decpt = INT_MAX; + return (nrv_alloc(INFSTR, rve, sizeof(INFSTR) - 1)); + default: /* FP_NAN or unrecognized */ + *decpt = INT_MAX; + return (nrv_alloc(NANSTR, rve, sizeof(NANSTR) - 1)); + } + + /* FP_NORMAL or FP_SUBNORMAL */ + + if (ndigits == 0) /* dtoa() compatibility */ + ndigits = 1; + + /* + * If ndigits < 0, we are expected to auto-size, so we allocate + * enough space for all the digits. + */ + bufsize = (ndigits > 0) ? ndigits : SIGFIGS; + s0 = rv_alloc(bufsize); + + /* Round to the desired number of digits. */ + if (SIGFIGS > ndigits && ndigits > 0) { + float redux = one[u.bits.sign]; + int offset = 4 * ndigits + LDBL_MAX_EXP - 4 - LDBL_MANT_DIG; +#ifdef __i386__ + oldprec = fpsetprec(FP_PE); +#endif + u.bits.exp = offset; + u.e += redux; + u.e -= redux; + *decpt += u.bits.exp - offset; +#ifdef __i386__ + fpsetprec(oldprec); +#endif + } + + mask_nbit_l(u); + manh = u.bits.manh; + manl = u.bits.manl; + *s0 = '1'; + for (s = s0 + 1; s < s0 + bufsize; s++) { + *s = xdigs[(manh >> (MANH_SIZE - 4)) & 0xf]; + manh = (manh << 4) | (manl >> (LDBL_MANL_SIZE - 4)); + manl <<= 4; + } + + /* If ndigits < 0, we are expected to auto-size the precision. */ + if (ndigits < 0) { + for (ndigits = SIGFIGS; s0[ndigits - 1] == '0'; ndigits--) + ; + } + + s = s0 + ndigits; + *s = '\0'; + if (rve != NULL) + *rve = 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) */ |