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#include <stdint.h>
#include <math.h>
double fma(double x, double y, double z) {
double xy, result;
union {double f; uint64_t i;} u;
int e;
xy = (double)x * y;
result = xy + z;
u.f = result;
e = u.i>>52 & 0x7ff;
if (
(u.i & 0x1fffffff) != 0x10000000 ||
e == 0x7ff ||
(result - xy == z && result - z == xy)
) {
z = result;
return z;
}
double err;
int neg = u.i >> 63;
if (neg == (z > xy))
err = xy - result + z;
else
err = z - result + xy;
if (neg == (err < 0))
u.i++;
else
u.i--;
z = u.f;
return z;
}
float fmaf(float x, float y, float z) {
return fma(x, y, z);
}
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