[Beignet] [PATCH] backend: refine convert_float_rtn(double x)

[rander]

	 deal with every corner case (-+inf, NAN...)when convert

Signed-off-by: rander <rander.wang at intel.com>
---
 backend/src/libocl/script/ocl_convert.sh | 35 +++++++++++++++++++++-----------
 1 file changed, 23 insertions(+), 12 deletions(-)

diff --git a/backend/src/libocl/script/ocl_convert.sh b/backend/src/libocl/script/ocl_convert.sh
index bc02de3..f063f09 100755
--- a/backend/src/libocl/script/ocl_convert.sh
+++ b/backend/src/libocl/script/ocl_convert.sh
@@ -657,23 +657,34 @@ OVERLOADABLE float  convert_float_rtn(double x)
 	long lval = as_long(x);
 	int exp = ((lval & DF_EXP_MASK) >> DF_EXP_OFFSET) - DF_EXP_BIAS;
 	int sign = (lval & DF_SIGN_MASK)?1:0;
+	long ma = (lval &DF_MAN_MASK);
 
-	ret = sign;
-	ret = (lval & DF_ABS_MASK) ? ret:0;
-	tmp = 0x1000000 >> (23 - (exp + 149));
+	int fval = ((exp + 127) << 23) |convert_int(ma >> 29);
+	if((ma & 0x1FFFFFFF) && sign) fval += 1;
+	ret = fval;
+
+	ma |= DF_IMPLICITE_ONE;
+	tmp = ma >> (-exp - 97);
+	long shift = (1UL << (-exp - 97)) -1UL;
+	if((ma & shift) && sign) tmp += 1;
 	ret = (exp < -126) ? tmp:ret;
-	long ma = (lval &DF_MAN_MASK);
-	tmp = (lval & DF_MAN_MASK) ? SF_NAN:SF_POSITIVE_INF;
-	ret = (exp == 1024) ? tmp:ret;
-	tmp = SF_POSITIVE_INF;
+
+	tmp = sign;
+	ret = (exp < -149) ? tmp:ret;
+
+	tmp = sign ? 0x7F800000:0x7F7FFFFF;
 	ret = (exp > 127) ? tmp:ret;
-	ret = (lval & DF_ABS_MASK) ? ret:0;
-	tmp = ((exp + 127) << 23) |convert_int(ma >> 29);
-	if((ma & 0x1FFFFFFF) && sign) tmp += 1;
-	ret = ((exp >= -126) && (exp <= 127)) ? tmp:ret;
+
+	tmp = (lval & DF_MAN_MASK) ? 0x7FFFFFFF:0x7F800000;
+	ret = (exp == 1024) ? tmp:ret;
+
+	tmp = sign ? (0xFF800000) : (0x7F7FFFFF);
+	ret = ((exp == 1023) && (ma == DF_MAN_MASK)) ? tmp:ret;
+
+	ret = ((lval & DF_ABS_MASK) == 0) ? 0:ret;
+
 	ret |= (sign << 31);
 	float ftemp = as_float(ret);
-
 	return ftemp;
 }
 
-- 
2.7.4