summaryrefslogtreecommitdiff log msg author committer range
path: root/src/math/ceil.c
blob: c2ab4a54866f15b0d067243d23feb8c4204ce489 (plain)
 ```1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 ``` ``````/* origin: FreeBSD /usr/src/lib/msun/src/s_ceil.c */ /* * ==================================================== * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved. * * Developed at SunPro, a Sun Microsystems, Inc. business. * Permission to use, copy, modify, and distribute this * software is freely granted, provided that this notice * is preserved. * ==================================================== */ /* * ceil(x) * Return x rounded toward -inf to integral value * Method: * Bit twiddling. * Exception: * Inexact flag raised if x not equal to ceil(x). */ #include "libm.h" static const double huge = 1.0e300; double ceil(double x) { int32_t i0,i1,j0; uint32_t i,j; EXTRACT_WORDS(i0, i1, x); // FIXME signed shift j0 = ((i0>>20)&0x7ff) - 0x3ff; if (j0 < 20) { if (j0 < 0) { /* raise inexact if x != 0 */ if (huge+x > 0.0) { /* return 0*sign(x) if |x|<1 */ if (i0 < 0) { i0 = 0x80000000; i1=0; } else if ((i0|i1) != 0) { i0=0x3ff00000; i1=0; } } } else { i = (0x000fffff)>>j0; if (((i0&i)|i1) == 0) /* x is integral */ return x; /* raise inexact flag */ if (huge+x > 0.0) { if (i0 > 0) i0 += 0x00100000>>j0; i0 &= ~i; i1 = 0; } } } else if (j0 > 51) { if (j0 == 0x400) /* inf or NaN */ return x+x; return x; /* x is integral */ } else { i = (uint32_t)0xffffffff>>(j0-20); if ((i1&i) == 0) return x; /* x is integral */ /* raise inexact flag */ if (huge+x > 0.0) { if (i0 > 0) { if (j0 == 20) i0 += 1; else { j = i1 + (1<<(52-j0)); if (j < i1) /* got a carry */ i0 += 1; i1 = j; } } i1 &= ~i; } } INSERT_WORDS(x, i0, i1); return x; } ``````