/* * ==================================================== * 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. * ==================================================== */ /* IEEE functions * nextafter(x,y) * return the next machine floating-point number of x in the * direction toward y. * Special cases: */ #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);