clean up pow.c and powf.c

[musl] / src / math / powf.c

diff --git a/src/math/powf.c b/src/math/powf.c
index c101d95..427c896 100644 (file)
--- a/src/math/powf.c
+++ b/src/math/powf.c
@@ -57,17 +57,15 @@ float powf(float x, float y)
        ix = hx & 0x7fffffff;
        iy = hy & 0x7fffffff;
 
-       /* y == 0: x**0 = 1 */
+       /* x**0 = 1, even if x is NaN */
        if (iy == 0)
                return 1.0f;
-
-       /* x == 1: 1**y = 1, even if y is NaN */
+       /* 1**y = 1, even if y is NaN */
        if (hx == 0x3f800000)
                return 1.0f;
-
-       /* y != 0: result is NaN if either arg is NaN */
+       /* NaN if either arg is NaN */
        if (ix > 0x7f800000 || iy > 0x7f800000)
-               return (x+0.0f) + (y+0.0f);
+               return x + y;
 
        /* determine if y is an odd int when x < 0
         * yisint = 0       ... y is not an integer
@@ -93,13 +91,10 @@ float powf(float x, float y)
                else if (ix > 0x3f800000)  /* (|x|>1)**+-inf = inf,0 */
                        return hy >= 0 ? y : 0.0f;
                else                       /* (|x|<1)**+-inf = 0,inf */
-                       return hy < 0 ? -y : 0.0f;
-       }
-       if (iy == 0x3f800000) {  /* y is +-1 */
-               if (hy < 0)
-                       return 1.0f/x;
-               return x;
+                       return hy >= 0 ? 0.0f: -y;
        }
+       if (iy == 0x3f800000)    /* y is +-1 */
+               return hy >= 0 ? x : 1.0f/x;
        if (hy == 0x40000000)    /* y is 2 */
                return x*x;
        if (hy == 0x3f000000) {  /* y is  0.5 */
@@ -122,15 +117,13 @@ float powf(float x, float y)
                return z;
        }
 
-       n = ((uint32_t)hx>>31) - 1;
-
-       /* (x<0)**(non-int) is NaN */
-       if ((n|yisint) == 0)
-               return (x-x)/(x-x);
-
-       sn = 1.0f; /* s (sign of result -ve**odd) = -1 else = 1 */
-       if ((n|(yisint-1)) == 0)  /* (-ve)**(odd int) */
-               sn = -1.0f;
+       sn = 1.0f; /* sign of result */
+       if (hx < 0) {
+               if (yisint == 0) /* (x<0)**(non-int) is NaN */
+                       return (x-x)/(x-x);
+               if (yisint == 1) /* (x<0)**(odd int) */
+                       sn = -1.0f;
+       }
 
        /* |y| is huge */
        if (iy > 0x4d000000) { /* if |y| > 2**27 */