add legacy scsi/scsi_ioctl.h header

[musl] / src / math / atan.c

diff --git a/src/math/atan.c b/src/math/atan.c
index d31782c..5a1d33e 100644 (file)
--- a/src/math/atan.c
+++ b/src/math/atan.c
@@ -60,34 +60,26 @@ static const double aT[] = {
   1.62858201153657823623e-02, /* 0x3F90AD3A, 0xE322DA11 */
 };
 
-static const double
-one = 1.0,
-huge = 1.0e300;
-
 double atan(double x)
 {
-       double w,s1,s2,z;
-       int32_t ix,hx,id;
+       double_t w,s1,s2,z;
+       uint32_t ix,sign;
+       int id;
 
-       GET_HIGH_WORD(hx, x);
-       ix = hx & 0x7fffffff;
+       GET_HIGH_WORD(ix, x);
+       sign = ix >> 31;
+       ix &= 0x7fffffff;
        if (ix >= 0x44100000) {   /* if |x| >= 2^66 */
-               uint32_t low;
-
-               GET_LOW_WORD(low, x);
-               if (ix > 0x7ff00000 ||
-                   (ix == 0x7ff00000 && low != 0))  /* NaN */
-                       return x+x;
-               if (hx > 0)
-                       return  atanhi[3] + *(volatile double *)&atanlo[3];
-               else
-                       return -atanhi[3] - *(volatile double *)&atanlo[3];
+               if (isnan(x))
+                       return x;
+               z = atanhi[3] + 0x1p-120f;
+               return sign ? -z : z;
        }
        if (ix < 0x3fdc0000) {    /* |x| < 0.4375 */
                if (ix < 0x3e400000) {  /* |x| < 2^-27 */
-                       /* raise inexact */
-                       if (huge+x > one)
-                               return x;
+                       /* raise inexact if x!=0 */
+                       FORCE_EVAL(x + 0x1p120f);
+                       return x;
                }
                id = -1;
        } else {
@@ -95,15 +87,15 @@ double atan(double x)
                if (ix < 0x3ff30000) {  /* |x| < 1.1875 */
                        if (ix < 0x3fe60000) {  /*  7/16 <= |x| < 11/16 */
                                id = 0;
-                               x = (2.0*x-one)/(2.0+x);
+                               x = (2.0*x-1.0)/(2.0+x);
                        } else {                /* 11/16 <= |x| < 19/16 */
                                id = 1;
-                               x = (x-one)/(x+one);
+                               x = (x-1.0)/(x+1.0);
                        }
                } else {
                        if (ix < 0x40038000) {  /* |x| < 2.4375 */
                                id = 2;
-                               x = (x-1.5)/(one+1.5*x);
+                               x = (x-1.5)/(1.0+1.5*x);
                        } else {                /* 2.4375 <= |x| < 2^66 */
                                id = 3;
                                x = -1.0/x;
@@ -119,5 +111,5 @@ double atan(double x)
        if (id < 0)
                return x - x*(s1+s2);
        z = atanhi[id] - (x*(s1+s2) - atanlo[id] - x);
-       return hx < 0 ? -z : z;
+       return sign ? -z : z;
 }