| 0,0 → 1,65 |
|---|
| /* |
| nextafterl.c |
| Contributed by Danny Smith <dannysmith@users.sourceforge.net> |
| No copyright claimed, absolutely no warranties. |
| |
| 2005-05-09 |
| */ |
| |
| #include <math.h> |
| |
| long double |
| nextafterl (long double x, long double y) |
| { |
| union { |
| long double ld; |
| struct { |
| unsigned long long mantissa; |
| unsigned short expn; |
| unsigned short pad; |
| } __attribute__ ((packed)) parts; |
| } u; |
| |
| /* The normal bit is explicit for long doubles, unlike |
| float and double. */ |
| static const unsigned long long normal_bit = 0x8000000000000000ull; |
| |
| if (isnan (y) || isnan (x)) |
| return x + y; |
| |
| if (x == y ) |
| /* nextafter (0.0, -O.0) should return -0.0. */ |
| return y; |
| |
| u.ld = x; |
| if (x == 0.0L) |
| { |
| u.parts.mantissa = 1ull; |
| return y > 0.0L ? u.ld : -u.ld; |
| } |
| |
| if (((x > 0.0L) ^ (y > x)) == 0) |
| { |
| u.parts.mantissa++; |
| if ((u.parts.mantissa & ~normal_bit) == 0ull) |
| u.parts.expn++; |
| } |
| else |
| { |
| if ((u.parts.mantissa & ~normal_bit) == 0ull) |
| u.parts.expn--; |
| u.parts.mantissa--; |
| } |
| |
| /* If we have updated the expn of a normal number, |
| or moved from denormal to normal, [re]set the normal bit. */ |
| |
| if (u.parts.expn & 0x7fff) |
| u.parts.mantissa |= normal_bit; |
| |
| return u.ld; |
| } |
| |
| /* nexttowardl is the same function with a different name. */ |
| long double |
| nexttowardl (long double, long double) __attribute__ ((alias("nextafterl"))); |