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 int32_t i1,jj0; 32 u_int32_t i,j,se,i0,sx; 33 GET_LDOUBLE_WORDS(se,i0,i1,x); 34 sx = (se>>15)&1; 35 jj0 = (se&0x7fff)-0x3fff; 36 if(jj0<31) { 37 if(jj0<0) { /* raise inexact if x != 0 */ 38 if(huge+x>0.0) {/* return 0*sign(x) if |x|<1 */ 39 if(sx) {se=0x8000;i0=0;i1=0;} 40 else if((i0|i1)!=0) { se=0x3fff;i0=0x80000000;i1=0;} 41 } 42 } else { 43 i = (0x7fffffff)>>jj0; 44 if(((i0&i)|i1)==0) return x; /* x is integral */ 45 if(huge+x>0.0) { /* raise inexact flag */ 46 if(sx==0) { 47 if (jj0>0 && (i0+(0x80000000>>jj0))>i0) 48 i0+=0x80000000>>jj0; 49 else 50 { 51 i = 0x7fffffff; 52 ++se; 53 } 54 } 55 i0 &= (~i); i1=0; 56 } 57 } 58 } else if (jj0>62) { 59 if(jj0==0x4000) return x+x; /* inf or NaN */ 60 else return x; /* x is integral */ 61 } else { 62 i = ((u_int32_t)(0xffffffff))>>(jj0-31); 63 if((i1&i)==0) return x; /* x is integral */ 64 if(huge+x>0.0) { /* raise inexact flag */ 65 if(sx==0) { 66 if(jj0==31) i0+=1; 67 else { 68 j = i1 + (1<<(63-jj0)); 69 if(j<(u_int32_t)i1) i0+=1; /* got a carry */ 70 i1 = j; 71 } 72 } 73 i1 &= (~i); 74 } 75 } 76 SET_LDOUBLE_WORDS(x,se,i0,i1); 77 return x; 78 } 79