Groups > comp.compilers > #1978

Re: Add nested-function support in a language the based on a stack-machine

From	John Levine <johnl@taugh.com>
Newsgroups	comp.compilers
Subject	Re: Add nested-function support in a language the based on a stack-machine
Date	2018-03-06 04:31 +0000
Organization	Taughannock Networks
Message-ID	<18-03-024@comp.compilers> (permalink)
References	<18-02-009@comp.compilers> <18-03-002@comp.compilers> <18-03-012@comp.compilers> <18-03-020@comp.compilers>

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>>>>This is because displays were found to be more costly for Algol-like
>>>>languages ...
>>
>>>> IIRC the additional cost is in updating the display on calls
>>>>and returns.

I get the impression that displays describe two different things.

One is a static array that has one entry for each level of lexical
scoping.  In a routine declared N levels (zero based) down, its prolog
saves the Nth entry in the display and replaces it with a pointer to
the current stack frame, and the epilog restores it.  It can assume
that higher level routines have correctly set entries 0:N-1.  That
seems pretty efficient.  Assuming the saved pointer is at a known
location in each stack frame you can do a longjmp and unwind stacks
without too much pain.

The other is the same array, but with a copy of the current display in
each routine's stack frame.  This is slower at call time but probably
faster to use on machines like S/360 without direct addressing
since the display on the stack is addressable from the frame pointer,
but static data needs to load a pointer from a constant pool.  A
longjmp doesn't need anything special since stacked displays go away
when the stack frames go away.

R's,
John

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Add nested-function support in a language the based on a stack-machine dror.openu@gmail.com - 2018-02-12 11:25 -0800
  Re: Add nested-function support in a language the based on a stack-machine dror.openu@gmail.com - 2018-02-12 14:16 -0800
    Re: Add nested-function support in a language the based on a stack-machine Hans-Peter Diettrich <DrDiettrich1@netscape.net> - 2018-02-13 12:10 +0100
  Re: Add nested-function support in a language the based on a stack-machine Louis Krupp <lkrupp@nospam.pssw.com.invalid> - 2018-02-13 00:42 -0700
    Re: Add nested-function support in a language the based on a stack-machine Kaz Kylheku <217-679-0842@kylheku.com> - 2018-02-14 00:59 +0000
      Re: Add nested-function support in a language the based on a stack-machine George Neuner <gneuner2@comcast.net> - 2018-02-13 22:04 -0500
        Re: Add nested-function support in a language the based on a stack-machine Kaz Kylheku <217-679-0842@kylheku.com> - 2018-02-14 18:06 +0000
          Re: Add nested-function support in a language the based on a stack-machine George Neuner <gneuner2@comcast.net> - 2018-02-15 11:41 -0500
            Re: Add nested-function support in a language the based on a stack-machine Kaz Kylheku <217-679-0842@kylheku.com> - 2018-02-17 16:13 +0000
              Re: Add nested-function support in a language the based on a stack-machine anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2018-02-17 16:39 +0000
                Re: Add nested-function support in a language the based on a stack-machine George Neuner <gneuner2@comcast.net> - 2018-03-01 13:48 -0500
                Re: Add nested-function support in a language the based on a stack-machine Kaz Kylheku <217-679-0842@kylheku.com> - 2018-03-01 19:26 +0000
                Re: Add nested-function support in a language the based on a stack-machine Kaz Kylheku <217-679-0842@kylheku.com> - 2018-03-02 00:38 +0000
                Re: Add nested-function support in a language the based on a stack-machine George Neuner <gneuner2@comcast.net> - 2018-03-02 02:48 -0500
                Re: Add nested-function support in a language the based on a stack-machine rpw3@rpw3.org (Rob Warnock) - 2018-03-03 16:00 +0000
                Re: Add nested-function support in a language the based on a stack-machine anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2018-03-02 09:30 +0000
                Re: Add nested-function support in a language the based on a stack-machine anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2018-03-05 15:01 +0000
                Re: Add nested-function support in a language the based on a stack-machine George Neuner <gneuner2@comcast.net> - 2018-03-05 15:51 -0500
                Re: Add nested-function support in a language the based on a stack-machine George Neuner <gneuner2@comcast.net> - 2018-03-05 14:39 -0500
                Re: Add nested-function support in a language the based on a stack-machine John Levine <johnl@taugh.com> - 2018-03-06 04:31 +0000
                Re: Add nested-function support in a language the based on a stack-machine Kaz Kylheku <217-679-0842@kylheku.com> - 2018-03-06 18:17 +0000
                Re: Add nested-function support in a language the based on a stack-machine Kaz Kylheku <157-073-9834@kylheku.com> - 2018-03-11 03:19 +0000
                Re: Add nested-function support in a language the based on a stack-machine Tomasz Kowaltowski <tk@ic.unicamp.br> - 2018-03-06 12:10 -0300
                Re: Add nested-function support in a language the based on a stack-machine bartc <bc@freeuk.com> - 2018-03-06 19:02 +0000
                Re: Add nested-function support in a language the based on a stack-machine antispam@math.uni.wroc.pl - 2018-04-29 16:29 +0000
              Re: Add nested-function support in a language the based on a stack-machine George Neuner <gneuner2@comcast.net> - 2018-03-01 13:49 -0500
    Re: Add nested-function support in a language the based on a stack-machine George Neuner <gneuner2@comcast.net> - 2018-02-13 22:37 -0500
  Re: Add nested-function support in a language the based on a stack-machine George Neuner <gneuner2@comcast.net> - 2018-02-13 23:27 -0500
  Re: Add nested-function support in a language the based on a stack-machine Shoefoot <shoefoot@gmail.com> - 2018-02-14 12:27 -0800

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