1*05a0b428SJohn Marino /*
2*05a0b428SJohn Marino * ====================================================
3*05a0b428SJohn Marino * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
4*05a0b428SJohn Marino *
5*05a0b428SJohn Marino * Developed at SunPro, a Sun Microsystems, Inc. business.
6*05a0b428SJohn Marino * Permission to use, copy, modify, and distribute this
7*05a0b428SJohn Marino * software is freely granted, provided that this notice
8*05a0b428SJohn Marino * is preserved.
9*05a0b428SJohn Marino * ====================================================
10*05a0b428SJohn Marino *
11*05a0b428SJohn Marino * From: @(#)s_floor.c 5.1 93/09/24
12*05a0b428SJohn Marino */
13*05a0b428SJohn Marino
14*05a0b428SJohn Marino /*
15*05a0b428SJohn Marino * truncl(x)
16*05a0b428SJohn Marino * Return x rounded toward 0 to integral value
17*05a0b428SJohn Marino * Method:
18*05a0b428SJohn Marino * Bit twiddling.
19*05a0b428SJohn Marino * Exception:
20*05a0b428SJohn Marino * Inexact flag raised if x not equal to truncl(x).
21*05a0b428SJohn Marino */
22*05a0b428SJohn Marino
23*05a0b428SJohn Marino #include <sys/types.h>
24*05a0b428SJohn Marino #include <machine/ieee.h>
25*05a0b428SJohn Marino
26*05a0b428SJohn Marino #include <float.h>
27*05a0b428SJohn Marino #include <math.h>
28*05a0b428SJohn Marino #include <stdint.h>
29*05a0b428SJohn Marino
30*05a0b428SJohn Marino #include "math_private.h"
31*05a0b428SJohn Marino
32*05a0b428SJohn Marino #ifdef LDBL_IMPLICIT_NBIT
33*05a0b428SJohn Marino #define MANH_SIZE (EXT_FRACHBITS + 1)
34*05a0b428SJohn Marino #else
35*05a0b428SJohn Marino #define MANH_SIZE EXT_FRACHBITS
36*05a0b428SJohn Marino #endif
37*05a0b428SJohn Marino
38*05a0b428SJohn Marino static const long double huge = 1.0e300;
39*05a0b428SJohn Marino static const float zero[] = { 0.0, -0.0 };
40*05a0b428SJohn Marino
41*05a0b428SJohn Marino long double
truncl(long double x)42*05a0b428SJohn Marino truncl(long double x)
43*05a0b428SJohn Marino {
44*05a0b428SJohn Marino int e, es;
45*05a0b428SJohn Marino uint32_t ix0, ix1;
46*05a0b428SJohn Marino
47*05a0b428SJohn Marino GET_LDOUBLE_WORDS(es,ix0,ix1,x);
48*05a0b428SJohn Marino e = (es&0x7fff) - LDBL_MAX_EXP + 1;
49*05a0b428SJohn Marino
50*05a0b428SJohn Marino if (e < MANH_SIZE - 1) {
51*05a0b428SJohn Marino if (e < 0) { /* raise inexact if x != 0 */
52*05a0b428SJohn Marino if (huge + x > 0.0)
53*05a0b428SJohn Marino return (zero[(es&0x8000)!=0]);
54*05a0b428SJohn Marino } else {
55*05a0b428SJohn Marino uint64_t m = ((1llu << MANH_SIZE) - 1) >> (e + 1);
56*05a0b428SJohn Marino if (((ix0 & m) | ix1) == 0)
57*05a0b428SJohn Marino return (x); /* x is integral */
58*05a0b428SJohn Marino if (huge + x > 0.0) { /* raise inexact flag */
59*05a0b428SJohn Marino ix0 &= ~m;
60*05a0b428SJohn Marino ix1 = 0;
61*05a0b428SJohn Marino }
62*05a0b428SJohn Marino }
63*05a0b428SJohn Marino } else if (e < LDBL_MANT_DIG - 1) {
64*05a0b428SJohn Marino uint64_t m = (uint64_t)-1 >> (64 - LDBL_MANT_DIG + e + 1);
65*05a0b428SJohn Marino if ((ix1 & m) == 0)
66*05a0b428SJohn Marino return (x); /* x is integral */
67*05a0b428SJohn Marino if (huge + x > 0.0) /* raise inexact flag */
68*05a0b428SJohn Marino ix1 &= ~m;
69*05a0b428SJohn Marino }
70*05a0b428SJohn Marino SET_LDOUBLE_WORDS(x,es,ix0,ix1);
71*05a0b428SJohn Marino return (x);
72*05a0b428SJohn Marino }
73