X-Git-Url: http://nsz.repo.hu/git/?p=musl;a=blobdiff_plain;f=src%2Fmath%2Ftgammal.c;h=5c1a02a6399692ca60037f346e4e1be1f8163f19;hp=1b8fddea1a3c5c4b4af89c815165291a7bf48d89;hb=d8a7619e371ff0f226200f6316abb46dd1192f3d;hpb=9e2a895aaaa4a3985e94ae4f3e24c1af65f9bb34

diff --git a/src/math/tgammal.c b/src/math/tgammal.c
index 1b8fddea..5c1a02a6 100644
--- a/src/math/tgammal.c
+++ b/src/math/tgammal.c
@@ -21,7 +21,6 @@
  * SYNOPSIS:
  *
  * long double x, y, tgammal();
- * extern int signgam;
  *
  * y = tgammal( x );
  *
@@ -29,10 +28,7 @@
  * DESCRIPTION:
  *
  * Returns gamma function of the argument.  The result is
- * correctly signed, and the sign (+1 or -1) is also
- * returned in a global (extern) variable named signgam.
- * This variable is also filled in by the logarithmic gamma
- * function lgamma().
+ * correctly signed.
  *
  * Arguments |x| <= 13 are reduced by recurrence and the function
  * approximated by a rational function of degree 7/8 in the
@@ -183,18 +179,18 @@ static long double stirf(long double x)
 {
 	long double y, w, v;
 
-	w = 1.0L/x;
+	w = 1.0/x;
 	/* For large x, use rational coefficients from the analytical expansion.  */
-	if (x > 1024.0L)
+	if (x > 1024.0)
 		w = (((((6.97281375836585777429E-5L * w
 		 + 7.84039221720066627474E-4L) * w
 		 - 2.29472093621399176955E-4L) * w
 		 - 2.68132716049382716049E-3L) * w
 		 + 3.47222222222222222222E-3L) * w
 		 + 8.33333333333333333333E-2L) * w
-		 + 1.0L;
+		 + 1.0;
 	else
-		w = 1.0L + w * __polevll(w, STIR, 8);
+		w = 1.0 + w * __polevll(w, STIR, 8);
 	y = expl(x);
 	if (x > MAXSTIR) { /* Avoid overflow in pow() */
 		v = powl(x, 0.5L * x - 0.25L);
@@ -209,77 +205,69 @@ static long double stirf(long double x)
 long double tgammal(long double x)
 {
 	long double p, q, z;
-	int i;
 
-	signgam = 1;
-	if (isnan(x))
-		return NAN;
-	if (x == INFINITY)
-		return INFINITY;
-	if (x == -INFINITY)
-		return x - x;
+	if (!isfinite(x))
+		return x + INFINITY;
+
 	q = fabsl(x);
-	if (q > 13.0L) {
-		if (q > MAXGAML)
-			goto goverf;
-		if (x < 0.0L) {
+	if (q > 13.0) {
+		if (x < 0.0) {
 			p = floorl(q);
-			if (p == q)
-				return (x - x) / (x - x);
-			i = p;
-			if ((i & 1) == 0)
-				signgam = -1;
 			z = q - p;
-			if (z > 0.5L) {
-				p += 1.0L;
-				z = q - p;
-			}
-			z = q * sinl(PIL * z);
-			z = fabsl(z) * stirf(q);
-			if (z <= PIL/LDBL_MAX) {
-goverf:
-				return signgam * INFINITY;
+			if (z == 0)
+				return 0 / z;
+			if (q > MAXGAML) {
+				z = 0;
+			} else {
+				if (z > 0.5) {
+					p += 1.0;
+					z = q - p;
+				}
+				z = q * sinl(PIL * z);
+				z = fabsl(z) * stirf(q);
+				z = PIL/z;
 			}
-			z = PIL/z;
+			if (0.5 * p == floorl(q * 0.5))
+				z = -z;
+		} else if (x > MAXGAML) {
+			z = x * 0x1p16383L;
 		} else {
 			z = stirf(x);
 		}
-		return signgam * z;
+		return z;
 	}
 
-	z = 1.0L;
-	while (x >= 3.0L) {
-		x -= 1.0L;
+	z = 1.0;
+	while (x >= 3.0) {
+		x -= 1.0;
 		z *= x;
 	}
 	while (x < -0.03125L) {
 		z /= x;
-		x += 1.0L;
+		x += 1.0;
 	}
 	if (x <= 0.03125L)
 		goto small;
-	while (x < 2.0L) {
+	while (x < 2.0) {
 		z /= x;
-		x += 1.0L;
+		x += 1.0;
 	}
-	if (x == 2.0L)
+	if (x == 2.0)
 		return z;
 
-	x -= 2.0L;
+	x -= 2.0;
 	p = __polevll(x, P, 7);
 	q = __polevll(x, Q, 8);
 	z = z * p / q;
-	if(z < 0)
-		signgam = -1;
 	return z;
 
 small:
-	if (x == 0.0L)
-		return (x - x) / (x - x);
-	if (x < 0.0L) {
+	/* z==1 if x was originally +-0 */
+	if (x == 0 && z != 1)
+		return x / x;
+	if (x < 0.0) {
 		x = -x;
 		q = z / (x * __polevll(x, SN, 8));
-		signgam = -1;
 	} else
 		q = z / (x * __polevll(x, S, 8));
 	return q;