🚀 go-pugleaf

> Actually, the architecture is based on numerous stacks.  Generally,
> each task will have one code stack and one data stack.  The use of
> libraries will increase the number of stacks associated with a task.

All running programs exist as stacks.  The system maintains a stack tree,
with the operating system as the root stack.

To make it easier to do reentrant code, an extra stack is used for the
"segment dictionary" of every running program.  Only one of these is
needed per unique program, no matter how many copies of it are running.
The segment dictionary contains descriptors for every code segment in
the program, and static data (value arrays, etc.).  Since this stuff never
changes, there is no need for more than one of these.

The MCP is called D0 because it is the root of everything; Display register
zero points to the base of its activation.  Segment dictionaries are called
D1 stacks because Display register one points to the base of their activation.
The outer block of a program is called a D2 stack because Display register two
points at the base of its activation.  Blocks called by the outer block run
at higher D (lex) levels.

For practical purposes, the D2 stacks are the running programs.  This stack
contains all active procedures and all data and all active expressions.

  =====================================================================
  = sua cuique voluptas              (everyone has his own pleasures) =
  = Randy Gellens            randy%mpa15ab@trenga.tredydev.unisys.com =
  = >>>>>>> If mail bounces, forward to rgellens@mcimail.com <<<<<<<< =
  = Opinions are personal; facts are suspect; I speak only for myself =

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Death is nature's way of telling you to slow down