Improve the documentation of the RenderScript API.

Only the explanations should be changing.

Change-Id: I889b366e3be44f5ac7f44a199e4b9a47353665e2
diff --git a/scriptc/rs_math.rsh b/scriptc/rs_math.rsh
index f78a0e1..0f094f6 100644
--- a/scriptc/rs_math.rsh
+++ b/scriptc/rs_math.rsh
@@ -17,9 +17,9 @@
 // Don't edit this file!  It is auto-generated by frameworks/rs/api/generate.sh.
 
 /*
- * rs_math.rsh: Mathematical functions
+ * rs_math.rsh: Mathematical Constants and Functions
  *
- * Most mathematical functions can be applied to scalars and vectors.
+ * The mathematical functions below can be applied to scalars and vectors.
  * When applied to vectors, a vector of the function applied to each entry
  * of the input is returned.
  *
@@ -33,8 +33,8 @@
  * a = sin(b);
  *
  *
- * A few functions like distance() and length() interpret instead the input
- * as a single vector in n-dimensional space.
+ * See "Vector math functions" for functions like distance() and length()
+ * that interpret instead the input as a single vector in n-dimensional space.
  *
  * The precision of the mathematical operations is affected by the pragmas
  * rs_fp_relaxed and rs_fp_full.
@@ -65,8 +65,11 @@
 #define M_2_PI 0.636619772367581343075535053490057448f
 
 /*
- * M_2_PIl: Deprecated.  Use M_2_PI instead.
+ * M_2_PIl: 2 / pi, as a 32 bit float
  *
+ * DEPRECATED.  Do not use.
+ *
+ * 2 divided by pi, as a 32 bit float.
  */
 #define M_2_PIl 0.636619772367581343075535053490057448f
 
@@ -4057,9 +4060,9 @@
 /*
  * rsClamp: Restrain a value to a range
  *
- * Clamp a value between low and high.
+ * DEPRECATED.  Do not use.
  *
- * Deprecated.  Use clamp() instead.
+ * Clamp a value between low and high.
  *
  * Parameters:
  *   amount: The value to clamp
@@ -4085,12 +4088,18 @@
     rsClamp(uint amount, uint low, uint high);
 
 /*
+ * rsFrac: Returns the fractional part of a float
+ *
+ * DEPRECATED.  Do not use.
+ *
  * Returns the fractional part of a float
  */
 extern float __attribute__((const, overloadable))
     rsFrac(float v);
 
 /*
+ * rsRand: Pseudo-random number
+ *
  * Return a random value between 0 (or min_value) and max_malue.
  */
 extern int __attribute__((overloadable))