1 /* sf_floor.c -- float version of s_floor.c.
2  * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
3  */
4 
5 /*
6  * ====================================================
7  * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
8  *
9  * Developed at SunPro, a Sun Microsystems, Inc. business.
10  * Permission to use, copy, modify, and distribute this
11  * software is freely granted, provided that this notice
12  * is preserved.
13  * ====================================================
14  */
15 
16 /*
17  * floorf(x)
18  * Return x rounded toward -inf to integral value
19  * Method:
20  *	Bit twiddling.
21  * Exception:
22  *	Inexact flag raised if x not equal to floorf(x).
23  */
24 
25 #include "fdlibm.h"
26 
27 #ifdef __STDC__
28 static const float huge = 1.0e30;
29 #else
30 static float huge = 1.0e30;
31 #endif
32 
33 #ifdef __STDC__
floorf(float x)34 	float floorf(float x)
35 #else
36 	float floorf(x)
37 	float x;
38 #endif
39 {
40 	__int32_t i0,j0;
41 	__uint32_t i,ix;
42 	GET_FLOAT_WORD(i0,x);
43 	ix = (i0&0x7fffffff);
44 	j0 = (ix>>23)-0x7f;
45 	if(j0<23) {
46 	    if(j0<0) { 	/* raise inexact if x != 0 */
47 		if(huge+x>(float)0.0) {/* return 0*sign(x) if |x|<1 */
48 		    if(i0>=0) {i0=0;}
49 		    else if(!FLT_UWORD_IS_ZERO(ix))
50 			{ i0=0xbf800000;}
51 		}
52 	    } else {
53 		i = (0x007fffff)>>j0;
54 		if((i0&i)==0) return x; /* x is integral */
55 		if(huge+x>(float)0.0) {	/* raise inexact flag */
56 		    if(i0<0) i0 += (0x00800000)>>j0;
57 		    i0 &= (~i);
58 		}
59 	    }
60 	} else {
61 	    if(!FLT_UWORD_IS_FINITE(ix)) return x+x;	/* inf or NaN */
62 	    else return x;		/* x is integral */
63 	}
64 	SET_FLOAT_WORD(x,i0);
65 	return x;
66 }
67 
68 #ifdef _DOUBLE_IS_32BITS
69 
70 #ifdef __STDC__
floor(double x)71 	double floor(double x)
72 #else
73 	double floor(x)
74 	double x;
75 #endif
76 {
77 	return (double) floorf((float) x);
78 }
79 
80 #endif /* defined(_DOUBLE_IS_32BITS) */
81