fix potentially wrong-sign zero in cproj functions at infinity

[musl] / src / math / atan.c

diff --git a/src/math/atan.c b/src/math/atan.c
index 7fd8a3b..63b0ab2 100644 (file)
--- a/src/math/atan.c
+++ b/src/math/atan.c
@@ -62,7 +62,7 @@ static const double aT[] = {
 
 double atan(double x)
 {
-       double w,s1,s2,z;
+       double_t w,s1,s2,z;
        uint32_t ix,sign;
        int id;
 
@@ -72,13 +72,14 @@ double atan(double x)
        if (ix >= 0x44100000) {   /* if |x| >= 2^66 */
                if (isnan(x))
                        return x;
-               z = atanhi[3] + 0x1p-1000;
+               z = atanhi[3] + 0x1p-120f;
                return sign ? -z : z;
        }
        if (ix < 0x3fdc0000) {    /* |x| < 0.4375 */
                if (ix < 0x3e400000) {  /* |x| < 2^-27 */
-                       /* raise inexact if x!=0 */
-                       FORCE_EVAL(x + 0x1p1000);
+                       if (ix < 0x00100000)
+                               /* raise underflow for subnormal x */
+                               FORCE_EVAL((float)x);
                        return x;
                }
                id = -1;