musl/src/math/scalbnl.c

#include "libm.h"

#if LDBL_MANT_DIG == 53 && LDBL_MAX_EXP == 1024
long double scalbnl(long double x, int n)
{
	return scalbn(x, n);
}
#elif (LDBL_MANT_DIG == 64 || LDBL_MANT_DIG == 113) && LDBL_MAX_EXP == 16384
long double scalbnl(long double x, int n)
{
	union ldshape u;

	if (n > 16383) {
		x *= 0x1p16383L;
		n -= 16383;
		if (n > 16383) {
			x *= 0x1p16383L;
			n -= 16383;
			if (n > 16383)
				n = 16383;
		}
	} else if (n < -16382) {
		x *= 0x1p-16382L * 0x1p113L;
		n += 16382 - 113;
		if (n < -16382) {
			x *= 0x1p-16382L * 0x1p113L;
			n += 16382 - 113;
			if (n < -16382)
				n = -16382;
		}
	}
	u.f = 1.0;
	u.i.se = 0x3fff + n;
	return x * u.f;
}
#endif