Exemple #1
0
long double
expl(long double x)
{
	union IEEEl2bits u;
	long double hi, lo, t, twopk;
	int k;
	uint16_t hx, ix;

	DOPRINT_START(&x);

	/* Filter out exceptional cases. */
	u.e = x;
	hx = u.xbits.expsign;
	ix = hx & 0x7fff;
	if (ix >= BIAS + 13) {		/* |x| >= 8192 or x is NaN */
		if (ix == BIAS + LDBL_MAX_EXP) {
			if (hx & 0x8000)  /* x is -Inf or -NaN */
				RETURNP(-1 / x);
			RETURNP(x + x);	/* x is +Inf or +NaN */
		}
		if (x > o_threshold)
			RETURNP(huge * huge);
		if (x < u_threshold)
			RETURNP(tiny * tiny);
	} else if (ix < BIAS - 114) {	/* |x| < 0x1p-114 */
		RETURN2P(1, x);		/* 1 with inexact iff x != 0 */
	}

	ENTERI();

	twopk = 1;
	__k_expl(x, &hi, &lo, &k);
	t = SUM2P(hi, lo);

	/* Scale by 2**k. */
	/* XXX sparc64 multiplication is so slow that scalbnl() is faster. */
	if (k >= LDBL_MIN_EXP) {
		if (k == LDBL_MAX_EXP)
			RETURNI(t * 2 * 0x1p16383L);
		SET_LDBL_EXPSIGN(twopk, BIAS + k);
		RETURNI(t * twopk);
	} else {
		SET_LDBL_EXPSIGN(twopk, BIAS + k + 10000);
		RETURNI(t * twopk * twom10000);
	}
}
Exemple #2
0
long double
expm1l(long double x)
{
	union IEEEl2bits u, v;
	long double fn, hx2_hi, hx2_lo, q, r, r1, r2, t, twomk, twopk, x_hi;
	long double x_lo, x2, z;
	long double x4;
	int k, n, n2;
	uint16_t hx, ix;

	DOPRINT_START(&x);

	/* Filter out exceptional cases. */
	u.e = x;
	hx = u.xbits.expsign;
	ix = hx & 0x7fff;
	if (ix >= BIAS + 6) {		/* |x| >= 64 or x is NaN */
		if (ix == BIAS + LDBL_MAX_EXP) {
			if (hx & 0x8000)  /* x is -Inf, -NaN or unsupported */
				RETURNP(-1 / x - 1);
			RETURNP(x + x);	/* x is +Inf, +NaN or unsupported */
		}
		if (x > o_threshold)
			RETURNP(huge * huge);
		/*
		 * expm1l() never underflows, but it must avoid
		 * unrepresentable large negative exponents.  We used a
		 * much smaller threshold for large |x| above than in
		 * expl() so as to handle not so large negative exponents
		 * in the same way as large ones here.
		 */
		if (hx & 0x8000)	/* x <= -64 */
			RETURN2P(tiny, -1);	/* good for x < -65ln2 - eps */
	}

	ENTERI();

	if (T1 < x && x < T2) {
		if (ix < BIAS - 74) {	/* |x| < 0x1p-74 (includes pseudos) */
			/* x (rounded) with inexact if x != 0: */
			RETURNPI(x == 0 ? x :
			    (0x1p100 * x + fabsl(x)) * 0x1p-100);
		}

		x2 = x * x;
		x4 = x2 * x2;
		q = x4 * (x2 * (x4 *
		    /*
		     * XXX the number of terms is no longer good for
		     * pairwise grouping of all except B3, and the
		     * grouping is no longer from highest down.
		     */
		    (x2 *            B12  + (x * B11 + B10)) +
		    (x2 * (x * B9 +  B8) +  (x * B7 +  B6))) +
			  (x * B5 +  B4.e)) + x2 * x * B3.e;

		x_hi = (float)x;
		x_lo = x - x_hi;
		hx2_hi = x_hi * x_hi / 2;
		hx2_lo = x_lo * (x + x_hi) / 2;
		if (ix >= BIAS - 7)
			RETURN2PI(hx2_hi + x_hi, hx2_lo + x_lo + q);
		else
			RETURN2PI(x, hx2_lo + q + hx2_hi);
	}

	/* Reduce x to (k*ln2 + endpoint[n2] + r1 + r2). */
	/* Use a specialized rint() to get fn.  Assume round-to-nearest. */
	fn = x * INV_L + 0x1.8p63 - 0x1.8p63;
#if defined(HAVE_EFFICIENT_IRINTL)
	n = irintl(fn);
#elif defined(HAVE_EFFICIENT_IRINT)
	n = irint(fn);
#else
	n = (int)fn;
#endif
	n2 = (unsigned)n % INTERVALS;
	k = n >> LOG2_INTERVALS;
	r1 = x - fn * L1;
	r2 = fn * -L2;
	r = r1 + r2;

	/* Prepare scale factor. */
	v.e = 1;
	v.xbits.expsign = BIAS + k;
	twopk = v.e;

	/*
	 * Evaluate lower terms of
	 * expl(endpoint[n2] + r1 + r2) = tbl[n2] * expl(r1 + r2).
	 */
	z = r * r;
	q = r2 + z * (A2 + r * A3) + z * z * (A4 + r * A5) + z * z * z * A6;

	t = (long double)tbl[n2].lo + tbl[n2].hi;

	if (k == 0) {
		t = SUM2P(tbl[n2].hi - 1, tbl[n2].lo * (r1 + 1) + t * q +
		    tbl[n2].hi * r1);
		RETURNI(t);
	}
	if (k == -1) {
		t = SUM2P(tbl[n2].hi - 2, tbl[n2].lo * (r1 + 1) + t * q +
		    tbl[n2].hi * r1);
		RETURNI(t / 2);
	}
	if (k < -7) {
		t = SUM2P(tbl[n2].hi, tbl[n2].lo + t * (q + r1));
		RETURNI(t * twopk - 1);
	}
	if (k > 2 * LDBL_MANT_DIG - 1) {
		t = SUM2P(tbl[n2].hi, tbl[n2].lo + t * (q + r1));
		if (k == LDBL_MAX_EXP)
			RETURNI(t * 2 * 0x1p16383L - 1);
		RETURNI(t * twopk - 1);
	}

	v.xbits.expsign = BIAS - k;
	twomk = v.e;

	if (k > LDBL_MANT_DIG - 1)
		t = SUM2P(tbl[n2].hi, tbl[n2].lo - twomk + t * (q + r1));
	else
		t = SUM2P(tbl[n2].hi - twomk, tbl[n2].lo + t * (q + r1));
	RETURNI(t * twopk);
}
Exemple #3
0
long double
expm1l(long double x)
{
	union IEEEl2bits u, v;
	long double hx2_hi, hx2_lo, q, r, r1, t, twomk, twopk, x_hi;
	long double x_lo, x2;
	double dr, dx, fn, r2;
	int k, n, n2;
	uint16_t hx, ix;

	DOPRINT_START(&x);

	/* Filter out exceptional cases. */
	u.e = x;
	hx = u.xbits.expsign;
	ix = hx & 0x7fff;
	if (ix >= BIAS + 7) {		/* |x| >= 128 or x is NaN */
		if (ix == BIAS + LDBL_MAX_EXP) {
			if (hx & 0x8000)  /* x is -Inf or -NaN */
				RETURNP(-1 / x - 1);
			RETURNP(x + x);	/* x is +Inf or +NaN */
		}
		if (x > o_threshold)
			RETURNP(huge * huge);
		/*
		 * expm1l() never underflows, but it must avoid
		 * unrepresentable large negative exponents.  We used a
		 * much smaller threshold for large |x| above than in
		 * expl() so as to handle not so large negative exponents
		 * in the same way as large ones here.
		 */
		if (hx & 0x8000)	/* x <= -128 */
			RETURN2P(tiny, -1);	/* good for x < -114ln2 - eps */
	}

	ENTERI();

	if (T1 < x && x < T2) {
		x2 = x * x;
		dx = x;

		if (x < T3) {
			if (ix < BIAS - 113) {	/* |x| < 0x1p-113 */
				/* x (rounded) with inexact if x != 0: */
				RETURNPI(x == 0 ? x :
				    (0x1p200 * x + fabsl(x)) * 0x1p-200);
			}
			q = x * x2 * C3 + x2 * x2 * (C4 + x * (C5 + x * (C6 +
			    x * (C7 + x * (C8 + x * (C9 + x * (C10 +
			    x * (C11 + x * (C12 + x * (C13 +
			    dx * (C14 + dx * (C15 + dx * (C16 +
			    dx * (C17 + dx * C18))))))))))))));
		} else {
			q = x * x2 * D3 + x2 * x2 * (D4 + x * (D5 + x * (D6 +
			    x * (D7 + x * (D8 + x * (D9 + x * (D10 +
			    x * (D11 + x * (D12 + x * (D13 +
			    dx * (D14 + dx * (D15 + dx * (D16 +
			    dx * D17)))))))))))));
		}

		x_hi = (float)x;
		x_lo = x - x_hi;
		hx2_hi = x_hi * x_hi / 2;
		hx2_lo = x_lo * (x + x_hi) / 2;
		if (ix >= BIAS - 7)
			RETURN2PI(hx2_hi + x_hi, hx2_lo + x_lo + q);
		else
			RETURN2PI(x, hx2_lo + q + hx2_hi);
	}

	/* Reduce x to (k*ln2 + endpoint[n2] + r1 + r2). */
	/* Use a specialized rint() to get fn.  Assume round-to-nearest. */
	fn = (double)x * INV_L + 0x1.8p52 - 0x1.8p52;
#if defined(HAVE_EFFICIENT_IRINT)
	n = irint(fn);
#else
	n = (int)fn;
#endif
	n2 = (unsigned)n % INTERVALS;
	k = n >> LOG2_INTERVALS;
	r1 = x - fn * L1;
	r2 = fn * -L2;
	r = r1 + r2;

	/* Prepare scale factor. */
	v.e = 1;
	v.xbits.expsign = BIAS + k;
	twopk = v.e;

	/*
	 * Evaluate lower terms of
	 * expl(endpoint[n2] + r1 + r2) = tbl[n2] * expl(r1 + r2).
	 */
	dr = r;
	q = r2 + r * r * (A2 + r * (A3 + r * (A4 + r * (A5 + r * (A6 +
	    dr * (A7 + dr * (A8 + dr * (A9 + dr * A10))))))));

	t = tbl[n2].lo + tbl[n2].hi;

	if (k == 0) {
		t = SUM2P(tbl[n2].hi - 1, tbl[n2].lo * (r1 + 1) + t * q +
		    tbl[n2].hi * r1);
		RETURNI(t);
	}
	if (k == -1) {
		t = SUM2P(tbl[n2].hi - 2, tbl[n2].lo * (r1 + 1) + t * q +
		    tbl[n2].hi * r1);
		RETURNI(t / 2);
	}
	if (k < -7) {
		t = SUM2P(tbl[n2].hi, tbl[n2].lo + t * (q + r1));
		RETURNI(t * twopk - 1);
	}
	if (k > 2 * LDBL_MANT_DIG - 1) {
		t = SUM2P(tbl[n2].hi, tbl[n2].lo + t * (q + r1));
		if (k == LDBL_MAX_EXP)
			RETURNI(t * 2 * 0x1p16383L - 1);
		RETURNI(t * twopk - 1);
	}

	v.xbits.expsign = BIAS - k;
	twomk = v.e;

	if (k > LDBL_MANT_DIG - 1)
		t = SUM2P(tbl[n2].hi, tbl[n2].lo - twomk + t * (q + r1));
	else
		t = SUM2P(tbl[n2].hi - twomk, tbl[n2].lo + t * (q + r1));
	RETURNI(t * twopk);
}