X-Git-Url: http://nsz.repo.hu/git/?p=musl;a=blobdiff_plain;f=src%2Fmath%2Flog2l.c;h=345b395daf6eafd340122c0c35b96ca6f6c4ee5b;hp=cf08b0a458c989c4a810f4361dc057ef9ba790f0;hb=6a4cfbdbe718a115a22629ad0cb2ae21391a0454;hpb=b69f695acedd4ce2798ef9ea28d834ceccc789bd

diff --git a/src/math/log2l.c b/src/math/log2l.c
index cf08b0a4..345b395d 100644
--- a/src/math/log2l.c
+++ b/src/math/log2l.c
@@ -50,11 +50,6 @@
  * In the tests over the interval exp(+-10000), the logarithms
  * of the random arguments were uniformly distributed over
  * [-10000, +10000].
- *
- * ERROR MESSAGES:
- *
- * log singularity:  x = 0; returns -INFINITY
- * log domain:       x < 0; returns NAN
  */
 
 #include "libm.h"
@@ -69,7 +64,7 @@ long double log2l(long double x)
  * 1/sqrt(2) <= x < sqrt(2)
  * Theoretical peak relative error = 6.2e-22
  */
-static long double P[] = {
+static const long double P[] = {
  4.9962495940332550844739E-1L,
  1.0767376367209449010438E1L,
  7.7671073698359539859595E1L,
@@ -78,7 +73,7 @@ static long double P[] = {
  3.4258224542413922935104E2L,
  1.0747524399916215149070E2L,
 };
-static long double Q[] = {
+static const long double Q[] = {
 /* 1.0000000000000000000000E0,*/
  2.3479774160285863271658E1L,
  1.9444210022760132894510E2L,
@@ -94,13 +89,13 @@ static long double Q[] = {
  * 1/sqrt(2) <= x < sqrt(2)
  * Theoretical peak relative error = 6.16e-22
  */
-static long double R[4] = {
+static const long double R[4] = {
  1.9757429581415468984296E-3L,
 -7.1990767473014147232598E-1L,
  1.0777257190312272158094E1L,
 -3.5717684488096787370998E1L,
 };
-static long double S[4] = {
+static const long double S[4] = {
 /* 1.00000000000000000000E0L,*/
 -2.6201045551331104417768E1L,
  1.9361891836232102174846E2L,
@@ -113,18 +108,17 @@ static long double S[4] = {
 
 long double log2l(long double x)
 {
-	volatile long double z;
-	long double y;
+	long double y, z;
 	int e;
 
 	if (isnan(x))
 		return x;
 	if (x == INFINITY)
 		return x;
-	if (x <= 0.0L) {
-		if (x == 0.0L)
-			return -INFINITY;
-		return NAN;
+	if (x <= 0.0) {
+		if (x == 0.0)
+			return -1/(x+0); /* -inf with divbyzero */
+		return 0/0.0f; /* nan with invalid */
 	}
 
 	/* separate mantissa from exponent */
@@ -139,12 +133,12 @@ long double log2l(long double x)
 	if (e > 2 || e < -2) {
 		if (x < SQRTH) {  /* 2(2x-1)/(2x+1) */
 			e -= 1;
-			z = x - 0.5L;
-			y = 0.5L * z + 0.5L;
+			z = x - 0.5;
+			y = 0.5 * z + 0.5;
 		} else {  /*  2 (x-1)/(x+1)   */
-			z = x - 0.5L;
-			z -= 0.5L;
-			y = 0.5L * x  + 0.5L;
+			z = x - 0.5;
+			z -= 0.5;
+			y = 0.5 * x + 0.5;
 		}
 		x = z / y;
 		z = x*x;
@@ -155,13 +149,13 @@ long double log2l(long double x)
 	/* logarithm using log(1+x) = x - .5x**2 + x**3 P(x)/Q(x) */
 	if (x < SQRTH) {
 		e -= 1;
-		x = ldexpl(x, 1) - 1.0L; /*  2x - 1  */
+		x = 2.0*x - 1.0;
 	} else {
-		x = x - 1.0L;
+		x = x - 1.0;
 	}
 	z = x*x;
 	y = x * (z * __polevll(x, P, 6) / __p1evll(x, Q, 7));
-	y = y - ldexpl(z, -1);   /* -0.5x^2 + ... */
+	y = y - 0.5*z;
 
 done:
 	/* Multiply log of fraction by log2(e)