diff options
Diffstat (limited to 'sysdeps/i386/fpu/s_nexttoward.c')
| -rw-r--r-- | sysdeps/i386/fpu/s_nexttoward.c | 101 |
1 files changed, 101 insertions, 0 deletions
diff --git a/sysdeps/i386/fpu/s_nexttoward.c b/sysdeps/i386/fpu/s_nexttoward.c new file mode 100644 index 0000000000..6b18df1532 --- /dev/null +++ b/sysdeps/i386/fpu/s_nexttoward.c @@ -0,0 +1,101 @@ +/* s_nexttoward.c + * Special i387 version + * Conversion from s_nextafter.c by Ulrich Drepper, Cygnus Support, + * drepper@cygnus.com. + */ + +/* + * ==================================================== + * 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. + * ==================================================== + */ + +#if defined(LIBM_SCCS) && !defined(lint) +static char rcsid[] = "$NetBSD: $"; +#endif + +/* IEEE functions + * nexttoward(x,y) + * return the next machine floating-point number of x in the + * direction toward y. + * Special cases: + */ + +#include "math.h" +#include "math_private.h" + +#ifdef __STDC__ + double __nexttoward(double x, long double y) +#else + double __nexttoward(x,y) + double x; + long double y; +#endif +{ + int32_t hx,ix,iy; + u_int32_t lx,hy,ly,esy; + + EXTRACT_WORDS(hx,lx,x); + GET_LDOUBLE_WORDS(esy,hy,ly,y); + ix = hx&0x7fffffff; /* |x| */ + iy = esy&0x7fff; /* |y| */ + + /* Intel's extended format has the normally implicit 1 explicit + present. Sigh! */ + if(((ix>=0x7ff00000)&&((ix-0x7ff00000)|lx)!=0) || /* x is nan */ + ((iy>=0x7fff)&&((hy&0x7fffffff)|ly)!=0)) /* y is nan */ + return x+y; + if((long double) x==y) return y; /* x=y, return y */ + if((ix|lx)==0) { /* x == 0 */ + double x2; + INSERT_WORDS(x,(esy&0x8000)<<16,1); /* return +-minsub */ + x2 = x*x; + if(x2==x) return x2; else return x; /* raise underflow flag */ + } + if(hx>=0) { /* x > 0 */ + if (esy>=0x8000||((ix>>20)&0x7ff)>iy-0x3c00 + || (((ix>>20)&0x7ff)==iy-0x3c00 + && (((hx<<11)|(lx>>21))>(hy&0x7fffffff) + || (((hx<<11)|(lx>>21))==(hy&0x7fffffff) + && (lx<<11)>ly)))) { /* x > y, x -= ulp */ + if(lx==0) hx -= 1; + lx -= 1; + } else { /* x < y, x += ulp */ + lx += 1; + if(lx==0) hx += 1; + } + } else { /* x < 0 */ + if (esy<0x8000||((ix>>20)&0x7ff)>iy-0x3c00 + || (((ix>>20)&0x7ff)==iy-0x3c00 + && (((hx<<11)|(lx>>21))>(hy&0x7fffffff) + || (((hx<<11)|(lx>>21))==(hy&0x7fffffff) + && (lx<<11)>ly)))) {/* x < y, x -= ulp */ + if(lx==0) hx -= 1; + lx -= 1; + } else { /* x > y, x += ulp */ + lx += 1; + if(lx==0) hx += 1; + } + } + hy = hx&0x7ff00000; + if(hy>=0x7ff00000) return x+x; /* overflow */ + if(hy<0x00100000) { /* underflow */ + double x2 = x*x; + if(x2!=x) { /* raise underflow flag */ + INSERT_WORDS(x2,hx,lx); + return x2; + } + } + INSERT_WORDS(x,hx,lx); + return x; +} +weak_alias (__nexttoward, nexttoward) +#ifdef NO_LONG_DOUBLE +strong_alias (__nexttoward, __nexttowardl) +weak_alias (__nexttoward, nexttowardl) +#endif |