oracle: add comment to sort explaining network principle

Author: Reisen

program/src/oracle/sort/sort_stable_base_gen.c

@@ -56,6 +56,9 @@ sort_gen( int n ) {
 //printf( "                     ulong   n ) { /* assumes n in [0,%i) */\n", n );
 
   printf( "  do { /* BEGIN AUTOGENERATED CODE (n=%2i) *****************************/\n", n );
+  printf( "    /* This network of comparators and fallthroughs implement a sorting network representation\n" );
+  printf( "       of an insertion sort. Each case acts as a sort pass with the fallthrough falling through\n" );
+  printf( "       to smaller ranges of the input. */\n");
   printf( "#   define SORT_STABLE_CE(i,j) u = x[(SORT_IDX_T)i]; v = x[(SORT_IDX_T)j]; c = SORT_BEFORE( v, u ); x[(SORT_IDX_T)i] = c ? v : u; x[(SORT_IDX_T)j] = c ? u : v\n" );
   printf( "    int        c;\n" );
   printf( "    SORT_KEY_T u;\n" );

program/src/oracle/sort/tmpl/sort_stable_base.c

@@ -1,4 +1,7 @@
   do { /* BEGIN AUTOGENERATED CODE (n= 7) *****************************/
+    /* This network of comparators and fallthroughs implement a sorting network representation
+       of an insertion sort. Each case acts as a sort pass with the fallthrough falling through
+       to smaller ranges of the input. */
 #   define SORT_STABLE_CE(i,j) u = x[(SORT_IDX_T)i]; v = x[(SORT_IDX_T)j]; c = SORT_BEFORE( v, u ); x[(SORT_IDX_T)i] = c ? v : u; x[(SORT_IDX_T)j] = c ? u : v
     int        c;
     SORT_KEY_T u;