Hello Arunkumar,

CONSTR(e, s, ws): This is used to construct header for the data nodes which contain more than one constructors e.g List, Tree etc

CONSTRW(s, e) and CONSTRP(s, e) : Are used to construct header for data nodes which contain single constructor e.g Pair.

No, that is not correct. CONSTR(c,s,ws) Construct a tag (i.e. a header for a data node) where there is a mixture of pointers and basic values amongst the data items: c = number of the constructor s = size = total number of data items in the node ws = number of data items which are pointers to other nodes The number of non-pointers is therefore (s - ws). The complete node has layout: | tag | pointers | non-pointers | CONSTRW(s,e) Construct a tag for a node containing a single basic data item (non-pointer), but it could be larger than a single word, e.g. Integer, Double. s = size = number of words occupied by the node e = extra information, a 2-bit flag used e.g. to indicate that a GMP Integer is negative. CONSTRP(s,e) Construct a tag for a value where there is a single constructor, and all the data items contained in it are pointers, e.g. Array. Used only by hand-written code - never generated by the compiler. s = size = number of pointers e = extra information, currently unused. I hope this helps, Malcolm