-/* origin: FreeBSD /usr/src/lib/msun/src/s_nextafterl.c */
-/*
- * ====================================================
- * 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 "libm.h"
#if LDBL_MANT_DIG == 53 && LDBL_MAX_EXP == 1024
{
return nextafter(x, y);
}
-#elif (LDBL_MANT_DIG == 64 || LDBL_MANT_DIG == 113) && LDBL_MAX_EXP == 16384
+#elif LDBL_MANT_DIG == 64 && LDBL_MAX_EXP == 16384
long double nextafterl(long double x, long double y)
{
- volatile long double t;
- union IEEEl2bits ux, uy;
-
- ux.e = x;
- uy.e = y;
+ union ldshape ux, uy;
- 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 (isnan(x) || isnan(y))
+ return x + y;
if (x == y)
- return y; /* x=y, return y */
- if (x == 0.0) {
- /* return +-minsubnormal */
- ux.bits.manh = 0;
- ux.bits.manl = 1;
- ux.bits.sign = uy.bits.sign;
- /* raise underflow flag */
- t = ux.e*ux.e;
- if (t == ux.e)
- return t;
- return ux.e;
- }
- if(x > 0.0 ^ x < y) { /* x -= ulp */
- if (ux.bits.manl == 0) {
- if ((ux.bits.manh&~LDBL_NBIT) == 0)
- ux.bits.exp--;
- ux.bits.manh = (ux.bits.manh - 1) | (ux.bits.manh & LDBL_NBIT);
+ return y;
+ ux.f = x;
+ if (x == 0) {
+ uy.f = y;
+ ux.i.m = 1;
+ ux.i.se = uy.i.se & 0x8000;
+ } else if ((x < y) == !(ux.i.se & 0x8000)) {
+ ux.i.m++;
+ if (ux.i.m << 1 == 0) {
+ ux.i.m = 1ULL << 63;
+ ux.i.se++;
}
- ux.bits.manl--;
- } else { /* x += ulp */
- ux.bits.manl++;
- 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++;
+ } else {
+ if (ux.i.m << 1 == 0) {
+ ux.i.se--;
+ if (ux.i.se)
+ ux.i.m = 0;
}
+ ux.i.m--;
}
- if (ux.bits.exp == 0x7fff) /* overflow */
- return x+x;
- if (ux.bits.exp == 0) { /* underflow */
- mask_nbit_l(ux);
- /* raise underflow flag */
- t = ux.e * ux.e;
- if (t != ux.e)
- return ux.e;
+ /* raise overflow if ux is infinite and x is finite */
+ if ((ux.i.se & 0x7fff) == 0x7fff)
+ return x + x;
+ /* raise underflow if ux is subnormal or zero */
+ if ((ux.i.se & 0x7fff) == 0)
+ FORCE_EVAL(x*x + ux.f*ux.f);
+ return ux.f;
+}
+#elif LDBL_MANT_DIG == 113 && LDBL_MAX_EXP == 16384
+long double nextafterl(long double x, long double y)
+{
+ union ldshape ux, uy;
+
+ if (isnan(x) || isnan(y))
+ return x + y;
+ if (x == y)
+ return y;
+ ux.f = x;
+ if (x == 0) {
+ uy.f = y;
+ ux.i.lo = 1;
+ ux.i.se = uy.i.se & 0x8000;
+ } else if ((x < y) == !(ux.i.se & 0x8000)) {
+ ux.i2.lo++;
+ if (ux.i2.lo == 0)
+ ux.i2.hi++;
+ } else {
+ if (ux.i2.lo == 0)
+ ux.i2.hi--;
+ ux.i2.lo--;
}
- return ux.e;
+ /* raise overflow if ux is infinite and x is finite */
+ if ((ux.i.se & 0x7fff) == 0x7fff)
+ return x + x;
+ /* raise underflow if ux is subnormal or zero */
+ if ((ux.i.se & 0x7fff) == 0)
+ FORCE_EVAL(x*x + ux.f*ux.f);
+ return ux.f;
}
#endif