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Memory Pool System Project

             THE DESIGN OF THE MEMORY POOL SYSTEM LIBRARY INTERFACE
                                 design.mps.lib
                               incomplete design
                               richard 1996-09-03

    INTRODUCTION

    .intro: This document is the design of the MPS Library Interface, a part of the
    plinth.

    .readership: Any MPS developer.  Any clients that are prepared to read this in
    order to get documentation.

    GOALS

    .goal: The goals of the MPS library interface are:

    .goal.host: To control the dependency of the MPS on the hosted ISO C library so
    that the core MPS remains freestanding (see design.mps.exec-env).

    .goal.free: To allow the core MPS convenient access to ISO C functionality that
    is provided on freestanding platforms (see design.mps.exec-env.std.com.free).

    DESCRIPTION

    Overview

    .overview.access: The core MPS needs to access functionality that could be
    provided by an ISO C hosted environment.

    .overview.hosted: The core MPS must not make direct use of any facilities in
    the hosted environment (design.mps.exec-env).  However, it is sensible to make
    use of them when the MPS is deployed in a hosted environment.

    .overview.hosted.indirect: The core MPS does not make any direct use of hosted
    ISO C library facilities.  Instead, it indirects through the MPS Library
    Interface, impl.h.mpslib.

    .overview.free: The core MPS can make direct use of freestanding ISO C library
    facilities and does not need to include any of the header files <limits.h>,
    <stdarg.h>, and <stddef.h> directly.

    .overview.complete: The MPS Library Interface can be considered as the complete
    "interface to ISO" (in that it provides direct access to facilities that we get
    in a freestanding environment and equivalents of any functionality we require
    from the hosted environment).

    .overview.provision.client: In a freestanding environment the client is
    expected to provide functions meeting this interface to the MPS.

    .overview.provision.hosted: In a hosted environment, impl.c.mpsliban may be
    used.  It just maps impl.h.mpslib directly onto the ISO C library equivalents.

     - MPS Library Interface Diagram

    Outside the Interface

    We provide impl.c.mpsliban to the client, for two reasons:

      1. he can use it to connect the MPS to the ISO C library if it exists,

      2. as an example of an implementation of the MPS Library Interface.

    IMPLEMENTATION

    .impl: The MPS Library Interface comprises a header file impl.h.mpslib
    (mpslib.h) and some documentation.

    .impl.decl: The header file defines the interface to definitions which parallel
    those parts of the non-freestanding ISO headers which are used by the MPS.

    .impl.include: The header file also includes the freestanding headers
    <limits.h>, <stdarg.h>, and <stddef.h> (and not <float.h>, though perhaps it
    should).

    NOTES

    .doc: User doc in doc.mps.guide.interface and doc.mps.guide.appendix-plinth.

    ATTACHMENT
       "MPS Library Interface Diagram"

## A. References

## B. Document History

2002-06-07 | RB | Converted from MMInfo database design document.

## C. Copyright and License

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