EXCH & GLOBAL_SUM/MAX macros: change to "logical" suffix (_R4,_R8,_RS,_RL)   correspondance between macro and S/R ; - reduce number of macro definitions (keep only those which are used);   can always call directly the corrresponding S/R if needed.
EXCH & GLOBAL_SUM/MAX macros: change to "logical" suffix (_R4,_R8,_RS,_RL)
  correspondance between macro and S/R ;
- reduce number of macro definitions (keep only those which are used);
  can always call directly the corrresponding S/R if needed.

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