diff options
Diffstat (limited to 'src/math/powf.c')
| -rw-r--r-- | src/math/powf.c | 35 |
1 files changed, 14 insertions, 21 deletions
diff --git a/src/math/powf.c b/src/math/powf.c index c101d95c..427c8965 100644 --- 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 */ |