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#include "libm.h"
#if LDBL_MANT_DIG == 53 && LDBL_MAX_EXP == 1024
double nexttoward(double x, long double y)
{
return nextafter(x, y);
}
#else
#define SIGN ((uint64_t)1<<63)
double nexttoward(double x, long double y)
{
union dshape ux;
int e;
if (isnan(x) || isnan(y))
return x + y;
if (x == y)
return y;
ux.value = x;
if (x == 0) {
ux.bits = 1;
if (signbit(y))
ux.bits |= SIGN;
} else if (x < y) {
if (signbit(x))
ux.bits--;
else
ux.bits++;
} else {
if (signbit(x))
ux.bits++;
else
ux.bits--;
}
e = ux.bits>>52 & 0x7ff;
/* raise overflow if ux.value is infinite and x is finite */
if (e == 0x7ff)
return x + x;
/* raise underflow if ux.value is subnormal or zero */
if (e == 0) {
volatile float z = x*x + ux.value*ux.value;
}
return ux.value;
}
#endif
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