1 /* $OpenBSD: ldtoa.c,v 1.4 2016/03/09 16:28:47 deraadt Exp $ */ 2 /*- 3 * Copyright (c) 2003 David Schultz <das (at) FreeBSD.ORG> 4 * All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 18 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 25 * SUCH DAMAGE. 26 */ 27 28 #include <sys/types.h> 29 #include <machine/ieee.h> 30 #include <float.h> 31 #include <stdint.h> 32 #include <limits.h> 33 #include <math.h> 34 #include <stdlib.h> 35 #include "gdtoaimp.h" 36 37 #if (LDBL_MANT_DIG > DBL_MANT_DIG) 38 39 /* 40 * ldtoa() is a wrapper for gdtoa() that makes it smell like dtoa(), 41 * except that the floating point argument is passed by reference. 42 * When dtoa() is passed a NaN or infinity, it sets expt to 9999. 43 * However, a long double could have a valid exponent of 9999, so we 44 * use INT_MAX in ldtoa() instead. 45 */ 46 char * 47 __ldtoa(long double *ld, int mode, int ndigits, int *decpt, int *sign, 48 char **rve) 49 { 50 FPI fpi = { 51 LDBL_MANT_DIG, /* nbits */ 52 LDBL_MIN_EXP - LDBL_MANT_DIG, /* emin */ 53 LDBL_MAX_EXP - LDBL_MANT_DIG, /* emax */ 54 FLT_ROUNDS, /* rounding */ 55 #ifdef Sudden_Underflow /* unused, but correct anyway */ 56 1 57 #else 58 0 59 #endif 60 }; 61 int be, kind; 62 char *ret; 63 struct ieee_ext *p = (struct ieee_ext *)ld; 64 uint32_t bits[(LDBL_MANT_DIG + 31) / 32]; 65 void *vbits = bits; 66 67 /* 68 * gdtoa doesn't know anything about the sign of the number, so 69 * if the number is negative, we need to swap rounding modes of 70 * 2 (upwards) and 3 (downwards). 71 */ 72 *sign = p->ext_sign; 73 fpi.rounding ^= (fpi.rounding >> 1) & p->ext_sign; 74 75 be = p->ext_exp - (LDBL_MAX_EXP - 1) - (LDBL_MANT_DIG - 1); 76 EXT_TO_ARRAY32(p, bits); 77 78 switch (fpclassify(*ld)) { 79 case FP_NORMAL: 80 kind = STRTOG_Normal; 81 #ifdef EXT_IMPLICIT_NBIT 82 bits[LDBL_MANT_DIG / 32] |= 1 << ((LDBL_MANT_DIG - 1) % 32); 83 #endif /* EXT_IMPLICIT_NBIT */ 84 break; 85 case FP_ZERO: 86 kind = STRTOG_Zero; 87 break; 88 case FP_SUBNORMAL: 89 kind = STRTOG_Denormal; 90 be++; 91 break; 92 case FP_INFINITE: 93 kind = STRTOG_Infinite; 94 break; 95 case FP_NAN: 96 kind = STRTOG_NaN; 97 break; 98 default: 99 abort(); 100 } 101 102 ret = gdtoa(&fpi, be, vbits, &kind, mode, ndigits, decpt, rve); 103 if (*decpt == -32768) 104 *decpt = INT_MAX; 105 return ret; 106 } 107 DEF_STRONG(__ldtoa); 108 109 #else /* (LDBL_MANT_DIG == DBL_MANT_DIG) */ 110 111 char * 112 __ldtoa(long double *ld, int mode, int ndigits, int *decpt, int *sign, 113 char **rve) 114 { 115 char *ret; 116 117 ret = dtoa((double)*ld, mode, ndigits, decpt, sign, rve); 118 if (*decpt == 9999) 119 *decpt = INT_MAX; 120 return ret; 121 } 122 DEF_STRONG(__ldtoa); 123 124 #endif /* (LDBL_MANT_DIG == DBL_MANT_DIG) */ 125
