[Beignet] [PATCH] backend: add double version of asin

[rander]

	copy from fdlibm and pass the cft after refined

Signed-off-by: rander <rander.wang at intel.com>
---
 backend/src/libocl/tmpl/ocl_math_common.tmpl.cl | 60 +++++++++++++++++++++++++
 backend/src/libocl/tmpl/ocl_math_common.tmpl.h  |  1 +
 2 files changed, 61 insertions(+)

diff --git a/backend/src/libocl/tmpl/ocl_math_common.tmpl.cl b/backend/src/libocl/tmpl/ocl_math_common.tmpl.cl
index 611c2e3..8cccf27 100644
--- a/backend/src/libocl/tmpl/ocl_math_common.tmpl.cl
+++ b/backend/src/libocl/tmpl/ocl_math_common.tmpl.cl
@@ -146,6 +146,66 @@ OVERLOADABLE double acosh(double x)
 	}
 }
 
+OVERLOADABLE double asin(double x)
+{
+    double one =  1.00000000000000000000e+00, /* 0x3FF00000, 0x00000000 */
+    huge =  1.000e+300,
+    pio2_hi =  1.57079632679489655800e+00, /* 0x3FF921FB, 0x54442D18 */
+    pio2_lo =  6.12323399573676603587e-17, /* 0x3C91A626, 0x33145C07 */
+    pio4_hi =  7.85398163397448278999e-01, /* 0x3FE921FB, 0x54442D18 */
+        /* coefficient for R(x^2) */
+    pS0 =  1.66666666666666657415e-01, /* 0x3FC55555, 0x55555555 */
+    pS1 = -3.25565818622400915405e-01, /* 0xBFD4D612, 0x03EB6F7D */
+    pS2 =  2.01212532134862925881e-01, /* 0x3FC9C155, 0x0E884455 */
+    pS3 = -4.00555345006794114027e-02, /* 0xBFA48228, 0xB5688F3B */
+    pS4 =  7.91534994289814532176e-04, /* 0x3F49EFE0, 0x7501B288 */
+    pS5 =  3.47933107596021167570e-05, /* 0x3F023DE1, 0x0DFDF709 */
+    qS1 = -2.40339491173441421878e+00, /* 0xC0033A27, 0x1C8A2D4B */
+    qS2 =  2.02094576023350569471e+00, /* 0x40002AE5, 0x9C598AC8 */
+    qS3 = -6.88283971605453293030e-01, /* 0xBFE6066C, 0x1B8D0159 */
+    qS4 =  7.70381505559019352791e-02; /* 0x3FB3B8C5, 0xB12E9282 */
+
+    double t,w,p,q,c,r,s;
+    int hx,ix;
+    hx = __HI(x);
+    ix = hx&0x7fffffff;
+    if(ix>= 0x3ff00000) {       /* |x|>= 1 */
+        if(((ix-0x3ff00000)|__LO(x))==0)
+            /* asin(1)=+-pi/2 with inexact */
+        return x*pio2_hi+x*pio2_lo;
+        return (x-x)/(x-x);     /* asin(|x|>1) is NaN */
+    } else if (ix<0x3fe00000) { /* |x|<0.5 */
+        if(ix<0x3e400000) {     /* if |x| < 2**-27 */
+        if(huge+x>one) return x;/* return x with inexact if x!=0*/
+        } else
+        t = x*x;
+        p = t*(pS0+t*(pS1+t*(pS2+t*(pS3+t*(pS4+t*pS5)))));
+        q = one+t*(qS1+t*(qS2+t*(qS3+t*qS4)));
+        w = p/q;
+        return x+x*w;
+    }
+    /* 1> |x|>= 0.5 */
+    w = one-fabs(x);
+    t = w*0.5;
+    p = t*(pS0+t*(pS1+t*(pS2+t*(pS3+t*(pS4+t*pS5)))));
+    q = one+t*(qS1+t*(qS2+t*(qS3+t*qS4)));
+    s = sqrt(t);
+    if(ix>=0x3FEF3333) {    /* if |x| > 0.975 */
+        w = p/q;
+        t = pio2_hi-(2.0*(s+s*w)-pio2_lo);
+    } else {
+        w  = s;
+        __setLow(&w, 0);
+        c  = (t-w*w)/(s+w);
+        r  = p/q;
+        p  = 2.0*s*r-(pio2_lo-2.0*c);
+        q  = pio4_hi-2.0*w;
+        t  = pio4_hi-(p-q);
+    }
+    if(hx>0) return t; else return -t;
+}
+
+
 OVERLOADABLE double ceil(double x)
 {
     double ret;
diff --git a/backend/src/libocl/tmpl/ocl_math_common.tmpl.h b/backend/src/libocl/tmpl/ocl_math_common.tmpl.h
index 5bd5b36..c296925 100644
--- a/backend/src/libocl/tmpl/ocl_math_common.tmpl.h
+++ b/backend/src/libocl/tmpl/ocl_math_common.tmpl.h
@@ -23,6 +23,7 @@
 OVERLOADABLE double acos(double x);
 OVERLOADABLE double acospi(double x);
 OVERLOADABLE double acosh(double x);
+OVERLOADABLE double asin(double x);
 OVERLOADABLE double ceil(double x);
 OVERLOADABLE double copysign(double x, double y);
 OVERLOADABLE double fabs(double x);
-- 
2.7.4