1 /* 2 * ==================================================== 3 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved. 4 * 5 * Developed at SunPro, a Sun Microsystems, Inc. business. 6 * Permission to use, copy, modify, and distribute this 7 * software is freely granted, provided that this notice 8 * is preserved. 9 * ==================================================== 10 * 11 * From: @(#)s_ceil.c 5.1 93/09/24 12 */ 13 14 #include <sys/cdefs.h> 15 __RCSID("$NetBSD: s_ceill.c,v 1.1 2013/11/11 23:57:34 joerg Exp $"); 16 #if 0 17 __FBSDID("$FreeBSD: head/lib/msun/src/s_ceill.c 176280 2008-02-14 15:10:34Z bde $"); 18 #endif 19 20 /* 21 * ceill(x) 22 * Return x rounded toward -inf to integral value 23 * Method: 24 * Bit twiddling. 25 * Exception: 26 * Inexact flag raised if x not equal to ceill(x). 27 */ 28 #include "namespace.h" 29 30 #include <float.h> 31 #include <math.h> 32 #include <stdint.h> 33 #include <machine/ieee.h> 34 35 #ifdef __HAVE_LONG_DOUBLE 36 37 #ifdef __weak_alias 38 __weak_alias(ceill, _ceill) 39 #endif 40 41 #ifdef LDBL_IMPLICIT_NBIT 42 #define MANH_SIZE (EXT_FRACHBITS + 1) 43 #define INC_MANH(ux, c) do { \ 44 uint64_t oi = ux.extu_frach; \ 45 ux.extu_frach += (c); \ 46 if (ux.extu_frach < oi) \ 47 ux.extu_exp++; \ 48 } while (0) 49 #else 50 #define MANH_SIZE EXT_FRACHBITS 51 #define INC_MANH(ux, c) do { \ 52 uint64_t oi = ux.extu_frach; \ 53 ux.extu_frach += (c); \ 54 if (ux.extu_frach < oi) { \ 55 ux.extu_exp++; \ 56 ux.extu_frach |= 1llu << (EXT_FRACHBITS - 1); \ 57 } \ 58 } while (0) 59 #endif 60 61 static const long double huge = 1.0e300; 62 63 long double 64 ceill(long double x) 65 { 66 union ieee_ext_u ux = { .extu_ld = x, }; 67 int e = ux.extu_exp - LDBL_MAX_EXP + 1; 68 69 if (e < MANH_SIZE - 1) { 70 if (e < 0) { /* raise inexact if x != 0 */ 71 if (huge + x > 0.0) 72 if (ux.extu_exp > 0 || 73 (ux.extu_frach | ux.extu_fracl) != 0) 74 ux.extu_ld = ux.extu_sign ? -0.0 : 1.0; 75 } else { 76 uint64_t m = ((1llu << MANH_SIZE) - 1) >> (e + 1); 77 if (((ux.extu_frach & m) | ux.extu_fracl) == 0) 78 return (x); /* x is integral */ 79 if (!ux.extu_sign) { 80 #ifdef LDBL_IMPLICIT_NBIT 81 if (e == 0) 82 ux.extu_exp++; 83 else 84 #endif 85 INC_MANH(ux, 1llu << (MANH_SIZE - e - 1)); 86 } 87 if (huge + x > 0.0) { /* raise inexact flag */ 88 ux.extu_frach &= ~m; 89 ux.extu_fracl = 0; 90 } 91 } 92 } else if (e < LDBL_MANT_DIG - 1) { 93 uint64_t m = (uint64_t)-1 >> (64 - LDBL_MANT_DIG + e + 1); 94 if ((ux.extu_fracl & m) == 0) 95 return (x); /* x is integral */ 96 if (!ux.extu_sign) { 97 if (e == MANH_SIZE - 1) 98 INC_MANH(ux, 1); 99 else { 100 uint64_t o = ux.extu_fracl; 101 ux.extu_fracl += 1llu << (LDBL_MANT_DIG - e - 1); 102 if (ux.extu_fracl < o) /* got a carry */ 103 INC_MANH(ux, 1); 104 } 105 } 106 if (huge + x > 0.0) /* raise inexact flag */ 107 ux.extu_fracl &= ~m; 108 } 109 return (ux.extu_ld); 110 } 111 112 #endif /* __HAVE_LONG_DOUBLE */ 113