1 /*- 2 * Copyright (c) 2003 David Schultz <das@FreeBSD.ORG> 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24 * SUCH DAMAGE. 25 */ 26 27 #include <sys/cdefs.h> 28 __FBSDID("$FreeBSD$"); 29 30 #include <float.h> 31 #include <inttypes.h> 32 #include <limits.h> 33 #include <math.h> 34 #include <stdlib.h> 35 #include "fpmath.h" 36 #include "gdtoaimp.h" 37 38 /* 39 * ldtoa() is a wrapper for gdtoa() that makes it smell like dtoa(), 40 * except that the floating point argument is passed by reference. 41 * When dtoa() is passed a NaN or infinity, it sets expt to 9999. 42 * However, a long double could have a valid exponent of 9999, so we 43 * use INT_MAX in ldtoa() instead. 44 */ 45 char * 46 __ldtoa(long double *ld, int mode, int ndigits, int *decpt, int *sign, 47 char **rve) 48 { 49 static FPI fpi = { 50 LDBL_MANT_DIG, /* nbits */ 51 LDBL_MIN_EXP - LDBL_MANT_DIG, /* emin */ 52 LDBL_MAX_EXP - LDBL_MANT_DIG, /* emax */ 53 FPI_Round_near, /* rounding */ 54 #ifdef Sudden_Underflow /* unused, but correct anyway */ 55 1 56 #else 57 0 58 #endif 59 }; 60 int be, kind; 61 char *ret; 62 union IEEEl2bits u; 63 uint32_t bits[(LDBL_MANT_DIG + 31) / 32]; 64 void *vbits = bits; 65 66 u.e = *ld; 67 *sign = u.bits.sign; 68 be = u.bits.exp - (LDBL_MAX_EXP - 1) - (LDBL_MANT_DIG - 1); 69 LDBL_TO_ARRAY32(u, bits); 70 71 switch (fpclassify(u.e)) { 72 case FP_NORMAL: 73 kind = STRTOG_Normal; 74 #ifdef LDBL_IMPLICIT_NBIT 75 bits[LDBL_MANT_DIG / 32] |= 1 << ((LDBL_MANT_DIG - 1) % 32); 76 #endif /* LDBL_IMPLICIT_NBIT */ 77 break; 78 case FP_ZERO: 79 kind = STRTOG_Zero; 80 break; 81 case FP_SUBNORMAL: 82 kind = STRTOG_Denormal; 83 #ifdef LDBL_IMPLICIT_NBIT 84 be++; 85 #endif 86 break; 87 case FP_INFINITE: 88 kind = STRTOG_Infinite; 89 break; 90 case FP_NAN: 91 kind = STRTOG_NaN; 92 break; 93 default: 94 abort(); 95 } 96 97 ret = gdtoa(&fpi, be, vbits, &kind, mode, ndigits, decpt, rve); 98 if (*decpt == -32768) 99 *decpt = INT_MAX; 100 return ret; 101 } 102