NOTES

List of LOWL constants:
- LCH LNM LICH: Basic type size information.
- NLREP SPREP TABREP QUTREP: Character-set independent information.

List of LOWL registers:
- A, the Numerical Register
- B, the Index Register
- C, the Character Register

List of LOWL system variables:
- FFPT, LFPT: Forward and Backward stack pointers.
- SRCPT, DSTPT: Source and Destination pointers for FMOVE and MOVE.

Errors in Lowl Documentation.

LOWL Map Manual.
Pg. 24: CON N-OF doesn't list CON -N-OF.

LOWL Supplement 3: ML/I
Pg. 7: MDOP has 2 exits: 1 for overflow and 2 for normal op.

MAJOR ISSUES IN MAPPING TO LLVM:

- LLVM doesn't have the concept of PC.
  This means that we have to find articulate ways to implement
  EXIT n and GOADD. While EXIT n could be solved by a double
  pass system (which could actually get rid as well of the
  table and string declaration systems) would be unhelpful
  for GOADD, where LOWL doesn't give us any idea about the
  maximum value contained in the variable.

- LLVM cannot let us use the stack, as it is function based.
  This means that in order to implement subroutines (which
  cannot be mplemented as LLVM function as some of them 
  might arbitrarily jump to basic block in the main function)
  we need to implement an artificial stack.
  The LLOWL manual help us by telling that "a dozen" -- 
  unknown if literal or figurative -- stack entries would
  be enough. It's still to test whether this applies to
  ML/I or not.