improve ioctl time64 conversion fallback framework

[musl] / src / math / cbrtf.c

diff --git a/src/math/cbrtf.c b/src/math/cbrtf.c
index 4a984b1..89c2c86 100644 (file)
--- a/src/math/cbrtf.c
+++ b/src/math/cbrtf.c
@@ -17,7 +17,8 @@
  * Return cube root of x
  */
 
-#include "libm.h"
+#include <math.h>
+#include <stdint.h>
 
 static const unsigned
 B1 = 709958130, /* B1 = (127-127.0/3-0.03306235651)*2**23 */
@@ -25,15 +26,10 @@ B2 = 642849266; /* B2 = (127-127.0/3-24/3-0.03306235651)*2**23 */
 
 float cbrtf(float x)
 {
-       double r,T;
-       float t;
-       int32_t hx;
-       uint32_t sign;
-       uint32_t high;
+       double_t r,T;
+       union {float f; uint32_t i;} u = {x};
+       uint32_t hx = u.i & 0x7fffffff;
 
-       GET_FLOAT_WORD(hx, x);
-       sign = hx & 0x80000000;
-       hx ^= sign;
        if (hx >= 0x7f800000)  /* cbrt(NaN,INF) is itself */
                return x + x;
 
@@ -41,28 +37,29 @@ float cbrtf(float x)
        if (hx < 0x00800000) {  /* zero or subnormal? */
                if (hx == 0)
                        return x;  /* cbrt(+-0) is itself */
-               SET_FLOAT_WORD(t, 0x4b800000);  /* set t = 2**24 */
-               t *= x;
-               GET_FLOAT_WORD(high, t);
-               SET_FLOAT_WORD(t, sign|((high&0x7fffffff)/3+B2));
+               u.f = x*0x1p24f;
+               hx = u.i & 0x7fffffff;
+               hx = hx/3 + B2;
        } else
-               SET_FLOAT_WORD(t, sign|(hx/3+B1));
+               hx = hx/3 + B1;
+       u.i &= 0x80000000;
+       u.i |= hx;
 
        /*
         * First step Newton iteration (solving t*t-x/t == 0) to 16 bits.  In
         * double precision so that its terms can be arranged for efficiency
         * without causing overflow or underflow.
         */
-       T = t;
+       T = u.f;
        r = T*T*T;
-       T = T*((double)x+x+r)/(x+r+r);
+       T = T*((double_t)x+x+r)/(x+r+r);
 
        /*
         * Second step Newton iteration to 47 bits.  In double precision for
         * efficiency and accuracy.
         */
        r = T*T*T;
-       T = T*((double)x+x+r)/(x+r+r);
+       T = T*((double_t)x+x+r)/(x+r+r);
 
        /* rounding to 24 bits is perfect in round-to-nearest mode */
        return T;