1 /* Single precision version of nexttoward.c.
2 Conversion to IEEE single float by Jakub Jelinek, jj@ultra.linux.cz. */
3 /*
4 * ====================================================
5 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
6 *
7 * Developed at SunPro, a Sun Microsystems, Inc. business.
8 * Permission to use, copy, modify, and distribute this
9 * software is freely granted, provided that this notice
10 * is preserved.
11 * ====================================================
12 */
13
14 /* IEEE functions
15 * __nexttowardfd(x,y)
16 * return the next machine floating-point number of x in the
17 * direction toward y.
18 * This is for machines which use different binary type for double and
19 * long double conditionally, y is long double equal to double.
20 * Special cases:
21 */
22
23 #include <errno.h>
24 #include <math.h>
25 #include <math-barriers.h>
26 #include <math_private.h>
27 #include <math_ldbl_opt.h>
28 #include <float.h>
29
30 float __nldbl_nexttowardf(float x, double y);
31
__nldbl_nexttowardf(float x,double y)32 float __nldbl_nexttowardf(float x, double y)
33 {
34 int32_t hx,hy,ix,iy;
35 uint32_t ly;
36
37 GET_FLOAT_WORD(hx,x);
38 EXTRACT_WORDS(hy,ly,y);
39 ix = hx&0x7fffffff; /* |x| */
40 iy = hy&0x7fffffff; /* |y| */
41
42 if((ix>0x7f800000) || /* x is nan */
43 ((iy>=0x7ff00000)&&((iy-0x7ff00000)|ly)!=0)) /* y is nan */
44 return x+y;
45 if((double) x==y) return y; /* x=y, return y */
46 if(ix==0) { /* x == 0 */
47 float u;
48 SET_FLOAT_WORD(x,(uint32_t)(hy&0x80000000)|1);/* return +-minsub*/
49 u = math_opt_barrier (x);
50 u = u * u;
51 math_force_eval (u); /* raise underflow flag */
52 return x;
53 }
54 if(hx>=0) { /* x > 0 */
55 if(x > y) /* x -= ulp */
56 hx -= 1;
57 else /* x < y, x += ulp */
58 hx += 1;
59 } else { /* x < 0 */
60 if(x < y) /* x -= ulp */
61 hx -= 1;
62 else /* x > y, x += ulp */
63 hx += 1;
64 }
65 hy = hx&0x7f800000;
66 if(hy>=0x7f800000) {
67 float u = x+x; /* overflow */
68 math_force_eval (u);
69 __set_errno (ERANGE);
70 }
71 if(hy<0x00800000) {
72 float u = x*x; /* underflow */
73 math_force_eval (u); /* raise underflow flag */
74 __set_errno (ERANGE);
75 }
76 SET_FLOAT_WORD(x,hx);
77 return x;
78 }
79
80 #if LONG_DOUBLE_COMPAT(libm, GLIBC_2_1)
81 compat_symbol (libm, __nldbl_nexttowardf, nexttowardf, GLIBC_2_1);
82 #endif
83