Glulx -- specification change log

3.1.3: (Jun 25, 2022)
    Added support for double-precision floating point. (32 double opcodes,
    and a gestalt selector for them.)
    Added the @hasundo and @discardundo opcodes, along with a gestalt
    selector.
    Updated license to CC BY-NC-SA 4.0.
    ADDITION (Oct 2022): Added double-precision opcodes to the selector
    table. (Thanks Teh-Bobo.)

3.1.2: (Aug 17, 2010)
    Added support for floating-point. (29 float opcodes, and a gestalt
    selector for them.)
    Deprecated 8-bit and 16-bit locals. Also deprecated the use of the
    copyb and copys opcodes with a local-variable operand.
    Noted that opcodes 0x1000 to 0x10FF are reserved for FyreVM; also
    gestalt selectors 0x1000 to 0x10FF, and I/O system 20.
    Clarified that you may not use @setmemsize when the memory heap is 
    active.
    Clarified that glk_put_string() cannot accept encoded Glulx strings.
    More accelerated functions (late update: March 27, 2014)

3.1.1: (Mar 11, 2009)
    Added support for accelerated function calls. This adds @accelfunc
    and @accelparam opcodes, and selectors to go along with them.
    Admitted that branching from one function to another is legal.
    (Interpreters have always permitted it.)

3.1.0: (Feb 11, 2007)
    Added support for block operations and heap memory allocation. This
    adds @mcopy, @mzero, @malloc, and @mfree opcodes, and selectors to
    go along with them.

3.0.0: (Aug 13, 2006)
    Added Unicode support. This means a new selector; a @streamunichar
    opcode; an E2 (Unicode) string type; a couple of new Unicode compression
    node types; and a type-14 call stub, for printing said node types.
    Note that a Glulx 3.0 interpreter can execute Glulx 2.0 game files.

2.0.0: (Mar 29, 2000)
    Added modular I/O system system; setiosys, getiosys opcodes to
    support it. The default I/O system is no longer Glk, which makes
    this an incompatible change.

(Previous versions were all called "1.0.0")

* : (Feb 15, 2000)
    Added search opcodes; jumpabs; callf opcodes; defined gestalt
    selectors

* : (Aug 17, 1999)
    Added support for compressed strings.

* : (Apr 1, 1999)
    Initial draft