diff options
Diffstat (limited to 'libm/src/s_nextafterl.c')
-rw-r--r-- | libm/src/s_nextafterl.c | 82 |
1 files changed, 82 insertions, 0 deletions
diff --git a/libm/src/s_nextafterl.c b/libm/src/s_nextafterl.c new file mode 100644 index 0000000..eacfd33 --- /dev/null +++ b/libm/src/s_nextafterl.c @@ -0,0 +1,82 @@ +/* @(#)s_nextafter.c 5.1 93/09/24 */ +/* + * ==================================================== + * 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. + * ==================================================== + */ + +#ifndef lint +static char rcsid[] = "$FreeBSD: src/lib/msun/src/s_nextafterl.c,v 1.1 2005/03/07 04:56:46 das Exp $"; +#endif + +/* IEEE functions + * nextafter(x,y) + * return the next machine floating-point number of x in the + * direction toward y. + * Special cases: + */ + +#include <sys/cdefs.h> +#include <float.h> + +#include "fpmath.h" +#include "math.h" +#include "math_private.h" + +#if LDBL_MAX_EXP != 0x4000 +#error "Unsupported long double format" +#endif + +long double +nextafterl(long double x, long double y) +{ + volatile long double t; + union IEEEl2bits ux, uy; + + ux.e = x; + uy.e = y; + + if ((ux.bits.exp == 0x7fff && + ((ux.bits.manh&~LDBL_NBIT)|ux.bits.manl) != 0) || + (uy.bits.exp == 0x7fff && + ((uy.bits.manh&~LDBL_NBIT)|uy.bits.manl) != 0)) + return x+y; /* x or y is nan */ + if(x==y) return y; /* x=y, return y */ + if(x==0.0) { + ux.bits.manh = 0; /* return +-minsubnormal */ + ux.bits.manl = 1; + ux.bits.sign = uy.bits.sign; + t = ux.e*ux.e; + if(t==ux.e) return t; else return ux.e; /* raise underflow flag */ + } + if(x>0.0 ^ x<y) { /* x -= ulp */ + if(ux.bits.manl==0) { + if ((ux.bits.manh&~LDBL_NBIT)==0) + ux.bits.exp -= 1; + ux.bits.manh = (ux.bits.manh - 1) | (ux.bits.manh & LDBL_NBIT); + } + ux.bits.manl -= 1; + } else { /* x += ulp */ + ux.bits.manl += 1; + if(ux.bits.manl==0) { + ux.bits.manh = (ux.bits.manh + 1) | (ux.bits.manh & LDBL_NBIT); + if ((ux.bits.manh&~LDBL_NBIT)==0) + ux.bits.exp += 1; + } + } + if(ux.bits.exp==0x7fff) return x+x; /* overflow */ + if(ux.bits.exp==0) { /* underflow */ + mask_nbit_l(ux); + t = ux.e * ux.e; + if(t!=ux.e) /* raise underflow flag */ + return ux.e; + } + return ux.e; +} + +__strong_reference(nextafterl, nexttowardl); |