1 /* $NetBSD: ldtoa.c,v 1.4 2007/02/23 17:45:59 christos Exp $ */ 2 3 /*- 4 * Copyright (c) 2003 David Schultz <das@FreeBSD.ORG> 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26 * SUCH DAMAGE. 27 */ 28 29 #include <sys/cdefs.h> 30 #if 0 31 __FBSDID("$FreeBSD: src/lib/libc/gdtoa/_ldtoa.c,v 1.2 2004/01/18 07:53:49 das Exp $"); 32 #else 33 __RCSID("$NetBSD: ldtoa.c,v 1.4 2007/02/23 17:45:59 christos Exp $"); 34 #endif 35 36 #include <float.h> 37 #include <inttypes.h> 38 #include <limits.h> 39 #include <math.h> 40 #include <stdlib.h> 41 #ifndef __vax__ 42 #include <machine/ieee.h> 43 #endif 44 #include "gdtoaimp.h" 45 46 /* 47 * ldtoa() is a wrapper for gdtoa() that makes it smell like dtoa(), 48 * except that the floating point argument is passed by reference. 49 * When dtoa() is passed a NaN or infinity, it sets expt to 9999. 50 * However, a long double could have a valid exponent of 9999, so we 51 * use INT_MAX in ldtoa() instead. 52 */ 53 char * 54 ldtoa(long double *ld, int mode, int ndigits, int *decpt, int *sign, char **rve) 55 { 56 #ifdef EXT_EXPBITS 57 static FPI fpi = { 58 LDBL_MANT_DIG, /* nbits */ 59 LDBL_MIN_EXP - LDBL_MANT_DIG, /* emin */ 60 LDBL_MAX_EXP - LDBL_MANT_DIG, /* emax */ 61 FPI_Round_near, /* rounding */ 62 #ifdef Sudden_Underflow /* unused, but correct anyway */ 63 1 64 #else 65 0 66 #endif 67 }; 68 int be, kind; 69 char *ret; 70 union ieee_ext_u u; 71 uint32_t bits[(LDBL_MANT_DIG + 31) / 32]; 72 73 u.extu_ld = *ld; 74 *sign = u.extu_ext.ext_sign; 75 be = u.extu_ext.ext_exp - (LDBL_MAX_EXP - 1) - (LDBL_MANT_DIG - 1); 76 EXT_TO_ARRAY32(u, bits); 77 78 switch (fpclassify(u.extu_ld)) { 79 case FP_NORMAL: 80 kind = STRTOG_Normal; 81 #ifdef LDBL_IMPLICIT_NBIT 82 bits[LDBL_MANT_DIG / 32] |= 1 << ((LDBL_MANT_DIG - 1) % 32); 83 #endif /* LDBL_IMPLICIT_NBIT */ 84 break; 85 case FP_ZERO: 86 kind = STRTOG_Zero; 87 break; 88 case FP_SUBNORMAL: 89 kind = STRTOG_Denormal; 90 #ifdef LDBL_IMPLICIT_NBIT 91 be++; 92 #endif 93 break; 94 case FP_INFINITE: 95 kind = STRTOG_Infinite; 96 break; 97 case FP_NAN: 98 kind = STRTOG_NaN; 99 break; 100 default: 101 abort(); 102 } 103 104 ret = gdtoa(&fpi, be, (ULong *)bits, &kind, mode, ndigits, decpt, rve); 105 if (*decpt == -32768) 106 *decpt = INT_MAX; 107 return ret; 108 #else 109 return dtoa((double)*ld, mode, ndigits, decpt, sign, rve); 110 #endif 111 } 112