projects / uclibc-ng.git / blame
| Commit | Line | Data |
|---|---|---|
| 7ce331c0 EA |
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 | #if defined(LIBM_SCCS) && !defined(lint) | |
| 14 | static char rcsid[] = "$NetBSD: s_ceil.c,v 1.8 1995/05/10 20:46:53 jtc Exp $"; | |
| 15 | #endif | |
| 16 | ||
| 17 | /* | |
| 18 | * ceil(x) | |
| 19 | * Return x rounded toward -inf to integral value | |
| 20 | * Method: | |
| 21 | * Bit twiddling. | |
| 22 | * Exception: | |
| 23 | * Inexact flag raised if x not equal to ceil(x). | |
| 24 | */ | |
| 25 | ||
| 26 | #include "math.h" | |
| 27 | #include "math_private.h" | |
| 28 | ||
| 29 | #ifdef __STDC__ | |
| 30 | static const double huge = 1.0e300; | |
| 31 | #else | |
| 32 | static double huge = 1.0e300; | |
| 33 | #endif | |
| 34 | ||
| 35 | #ifdef __STDC__ | |
| 36 | double ceil(double x) | |
| 37 | #else | |
| 38 | double ceil(x) | |
| 39 | double x; | |
| 40 | #endif | |
| 41 | { | |
| 42 | int32_t i0,i1,j0; | |
| 43 | u_int32_t i,j; | |
| 44 | EXTRACT_WORDS(i0,i1,x); | |
| 45 | j0 = ((i0>>20)&0x7ff)-0x3ff; | |
| 46 | if(j0<20) { | |
| 47 | if(j0<0) { /* raise inexact if x != 0 */ | |
| 48 | if(huge+x>0.0) {/* return 0*sign(x) if |x|<1 */ | |
| 49 | if(i0<0) {i0=0x80000000;i1=0;} | |
| 50 | else if((i0|i1)!=0) { i0=0x3ff00000;i1=0;} | |
| 51 | } | |
| 52 | } else { | |
| 53 | i = (0x000fffff)>>j0; | |
| 54 | if(((i0&i)|i1)==0) return x; /* x is integral */ | |
| 55 | if(huge+x>0.0) { /* raise inexact flag */ | |
| 56 | if(i0>0) i0 += (0x00100000)>>j0; | |
| 57 | i0 &= (~i); i1=0; | |
| 58 | } | |
| 59 | } | |
| 60 | } else if (j0>51) { | |
| 61 | if(j0==0x400) return x+x; /* inf or NaN */ | |
| 62 | else return x; /* x is integral */ | |
| 63 | } else { | |
| 64 | i = ((u_int32_t)(0xffffffff))>>(j0-20); | |
| 65 | if((i1&i)==0) return x; /* x is integral */ | |
| 66 | if(huge+x>0.0) { /* raise inexact flag */ | |
| 67 | if(i0>0) { | |
| 68 | if(j0==20) i0+=1; | |
| 69 | else { | |
| 70 | j = i1 + (1<<(52-j0)); | |
| 71 | if(j<i1) i0+=1; /* got a carry */ | |
| 72 | i1 = j; | |
| 73 | } | |
| 74 | } | |
| 75 | i1 &= (~i); | |
| 76 | } | |
| 77 | } | |
| 78 | INSERT_WORDS(x,i0,i1); | |
| 79 | return x; | |
| 80 | } | |
| 26d7ea91 | 81 |