1 /* @(#)s_ceil.c 5.1 93/09/24 */ 2 /* 3 * ==================================================== 4 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved. 5 * 6 * Developed at SunPro, a Sun Microsystems, Inc. business. 7 * Permission to use, copy, modify, and distribute this 8 * software is freely granted, provided that this notice 9 * is preserved. 10 * ==================================================== 11 */ 12 13 /* 14 * ceill(x) 15 * Return x rounded toward -inf to integral value 16 * Method: 17 * Bit twiddling. 18 * Exception: 19 * Inexact flag raised if x not equal to ceil(x). 20 */ 21 22 #include <math.h> 23 24 #include "math_private.h" 25 26 static const long double huge = 1.0e4930L; 27 28 long double 29 ceill(long double x) 30 { 31 int64_t i0,i1,jj0; 32 u_int64_t i,j; 33 GET_LDOUBLE_WORDS64(i0,i1,x); 34 jj0 = ((i0>>48)&0x7fff)-0x3fff; 35 if(jj0<48) { 36 if(jj0<0) { /* raise inexact if x != 0 */ 37 if(huge+x>0.0) {/* return 0*sign(x) if |x|<1 */ 38 if(i0<0) {i0=0x8000000000000000ULL;i1=0;} 39 else if((i0|i1)!=0) { i0=0x3fff000000000000ULL;i1=0;} 40 } 41 } else { 42 i = (0x0000ffffffffffffULL)>>jj0; 43 if(((i0&i)|i1)==0) return x; /* x is integral */ 44 if(huge+x>0.0) { /* raise inexact flag */ 45 if(i0>0) i0 += (0x0001000000000000LL)>>jj0; 46 i0 &= (~i); i1=0; 47 } 48 } 49 } else if (jj0>111) { 50 if(jj0==0x4000) return x+x; /* inf or NaN */ 51 else return x; /* x is integral */ 52 } else { 53 i = -1ULL>>(jj0-48); 54 if((i1&i)==0) return x; /* x is integral */ 55 if(huge+x>0.0) { /* raise inexact flag */ 56 if(i0>0) { 57 if(jj0==48) i0+=1; 58 else { 59 j = i1+(1LL<<(112-jj0)); 60 if(j<i1) i0 +=1 ; /* got a carry */ 61 i1=j; 62 } 63 } 64 i1 &= (~i); 65 } 66 } 67 SET_LDOUBLE_WORDS64(x,i0,i1); 68 return x; 69 } 70