u3: adds comments to road pave implementations
@@ -522,6 +522,8 @@ _pave_north(c3_w* mem_w, c3_w siz_w, c3_w len_w)
// the stack starts at the end of the memory segment,
// minus space for the road structure [siz_w]
//
+ // NB: the returned road is "above" the stack
+ //
c3_w* rut_w = mem_w;
c3_w* mat_w = ((mem_w + len_w) - siz_w);
c3_w* cap_w = mat_w;
@@ -540,6 +542,8 @@ _pave_south(c3_w* mem_w, c3_w siz_w, c3_w len_w)
// the stack starts at the base memory pointer [mem_w],
// and ends after the space for the road structure [siz_w]
//
+ // NB: the returned road is *on* the stack
+ //
c3_w* rut_w = (mem_w + len_w);
c3_w* mat_w = mem_w;
c3_w* cap_w = mat_w + siz_w;
