Summary of Z-Machine Version Differences

Section numbers refer to the Z-Machine Standards Document 1.0. “Standard 1.0” and “Standard 1.1” refer to the revisions of the Standards Document.

Memory Limits

 

V1

V2

V3

V4

V5

V6

V7

V8

Maximum story length (1.1.4)

128 KB

128 KB

128 KB

256 KB

256 KB

512 KB

512 KB[*]

512 KB

Address packing factor (1.2.3)

2

2

2

4

4

4, with offsets

4, with offsets

8

Number of properties (12.2)

31

31

31

63

63

63

63

63

Maximum number of objects (12.3.1, 12.3.2)

255

255

255

65535

65535

65535

65535

65535

Number of attributes (12.3.1, 12.3.2)

32

32

32

48

48

48

48

48

Maximum property length (12.4.1, 12.4.2)

8

8

8

64

64

64

64

64

Text Encoding

 

V1

V2

V3

V4

V5

V6

V7

V8

Shift lock characters (3.2.2, 3.2.3, Standard 1.1)

Yes

Yes

-

-

-

-

-

-

Abbreviations (3.3)

-

32

96

96

96

96

96

96

Newline character (3.5.2, 3.5.3)

Character 1 in all alphabets

Character 7 in A2

Character 7 in A2

Character 7 in A2

Character 7 in A2

Character 7 in A2

Character 7 in A2

Character 7 in A2

Standard alphabet A2 (3.5.3, 3.5.4)

Includes “<”

Includes newline

Includes newline

Includes newline

Includes newline

Includes newline

Includes newline

Includes newline

Custom alphabet table (3.5.5, 11.1)

-

-

-

-

Yes

Yes

Yes

Yes

Dictionary resolution (3.7, 13.3, 13.4)

6

6

6

9

9

9

9

9

Custom Unicode table (3.8.5.2, 11.1)

-

-

-

-

Yes

Yes

Yes

Yes

Dictionary words ending with truncated characters have no end bit (Standard 1.1)

Yes

Yes

-

-

-

-

-

-

I/O

 

V1

V2

V3

V4

V5

V6

V7

V8

Undo (6.1.4)

-

-

-

-

Yes

Yes

Yes

Yes

Timed input (6.4, 10.5.3)

-

-

-

Yes

Yes

Yes

Yes

Yes

Sound effect interrupt (6.4)

-

-

-

-

Yes

Yes

Yes

Yes

Newline interrupt (6.4)

-

-

-

-

-

Yes

-

-

Player input copied to transcript (7.1.1.1)

Yes

Yes

Yes

Yes

Yes

-

Yes

Yes

Output streams 3 and 4 (7.1.2)

-

-

Yes

Yes

Yes

Yes

Yes

Yes

Buffer control (7.2.1)

-

-

-

Yes

Yes

Yes

Yes

Yes

Output stream 1 can be turned off (7.3, 7.4)

-

-

Yes

Yes

Yes

Yes

Yes

Yes

Load/save arbitrary files (7.6)

-

-

-

-

Yes

Yes

Yes

Yes

Sound effects (9.1)

-

-

Yes

Yes

Yes

Yes

Yes

Yes

Sound effect bits in header (9.1.1, 9.1.2)

-

-

-

-

Flags 2 bit 7

Flags 2 bit 7 and Flags 1 bit 5

Flags 2 bit 7

Flags 2 bit 7

Sound effects can repeat (9.4.3)

-

-

-

-

Yes

Yes

Yes

Yes

Input stream 1 (10.2)

-

-

Yes

Yes

Yes

Yes

Yes

Yes

Mouse (10.3)

-

-

-

-

Yes

Yes

Yes

Yes

Directly readable mouse buttons (10.3.3)

-

-

-

-

-

Yes

-

-

Mouse can be constrained to windows (10.3.4)

-

-

-

-

-

Yes

-

-

Mouse menus (10.4)

-

-

-

-

-

Yes

-

-

Terminating characters table (10.5.2.1)

-

-

 

-

Yes

Yes

Yes

Yes

Single character input (10.6)

-

-

-

Yes

Yes

Yes

Yes

Yes

Line input buffer byte 0 (15.read)

Maximum input length minus 1

Maximum input length minus 1

Maximum input length minus 1

Maximum input length minus 1

Maximum input length

Maximum input length

Maximum input length

Maximum input length

Line input buffer byte 1 (15.read)

First returned character

First returned character

First returned character

First returned character

Length of text

Length of text

Length of text

Length of text

Line input text has zero terminator (15.read)

Yes

Yes

Yes

Yes

-

-

-

-

Line input tokenization is optional (15.read)

-

-

-

-

Yes

Yes

Yes

Yes

Screen Model

 

V1

V2

V3

V4

V5

V6

V7

V8

Font size written to header (8.1.1, 11.1)

-

-

-

-

Width, height

Height, width

Width, height

Width, height

Character graphics bit in header (8.1.5.1, 11.1)

-

-

-

-

Yes

-

Yes

Yes

Interpreter responsible for status line (8.2, 10.5.1)

Yes

Yes

Yes, and set header bit if unable to provide

-

-

-

-

-

“Time game” bit in header (8.2.1, 11.1)

-

-

Yes

-

-

-

-

-

Colored text output (8.3)

-

-

-

-

Yes

Yes, per window

Yes

Yes

Colors 10-12 and -1 supported (8.4)

-

-

-

-

-

Yes

-

-

Interpreter writes default colors in header even if colors not supported (8.3.2)

-

-

-

-

-

Yes

-

-

Screen size in units written to header (8.4.3)

-

-

-

-

Yes

Yes

Yes

Yes

Screen windows (8.6.1, 8.7.2, 8.8.3)

1

1

2

2

2

8

2

2

Clear upper window when splitting (8.6.1.1.2)

-

-

Yes

-

-

-

-

-

Initial lower window cursor position (8.6.3, 8.7.2.2)

Bottom

Bottom

Bottom

Bottom

Top

Top[†]

Top

Top

Text styles (8.7.1)

-

-

-

Yes

Yes

Yes

Yes

Yes

Game can move cursor (8.7.2.3, 8.8.3.5)

-

-

-

Yes, upper window only

Yes, upper window only

Yes, all windows

Yes, upper window only

Yes, upper window only

Upper window always fixed-pitch (8.7.2.4)

-

-

-

Yes

Yes

-

Yes

Yes

Upper window never buffered (8.7.2.5)

-

-

Yes

Yes

Yes

-

Yes

Yes

Cursor movement after @erase_window (8.7.3.2.1)

-

-

-

Bottom left for lower window, top left for upper window

Top left

Top left

Top left

Top left

Interpreter sets header bit to request status line redraw (8.8.2)

-

-

-

-

-

Yes

-

-

Overlapping, movable windows (8.8.3)

-

-

-

-

-

Yes

 

 

Window attributes and properties (8.8.3.1, 8.8.3.2)

-

-

-

-

-

Yes

-

-

Pictures (8.8.6)

-

-

-

-

-

Yes

-

-

Header Fields

 

V1

V2

V3

V4

V5

V6

V7

V8

Original Flags 1 bits (11.1)

-

-

1, 2, 4, 5, 6

-

-

-

-

-

New Flags 1 bits (11.1)

-

-

-

2, 3, 4, 7

0, 2, 3, 4, 7

0, 1, 2, 3, 4, 5, 7

0, 2, 3, 4, 7

0, 2, 3, 4, 7

Flags 2 bits (11.1)

0

0

0, 1

0, 1

0, 1, 3, 4, 5, 6, 7

0, 1, 2, 3, 4, 5, 6, 7, 8

0, 1, 3, 4, 5, 6, 7

0, 1, 3, 4, 5, 6, 7

File length and checksum in header (11.1)

-

-

Yes

Yes

Yes

Yes

Yes

Yes

Interpreter number and version in header (11.1)

-

-

-

Yes

Yes

Yes

Yes

Yes

Screen size (rows/columns) in header (11.1)

-

-

-

Yes

Yes

Yes

Yes

Yes

Screen size (units) in header (11.1)

-

-

-

-

Yes

Yes

Yes

Yes

Routine and string offsets in header (11.1)

-

-

-

-

-

Yes

-

-

Output stream 3 total width written to header (11.1)

-

-

-

-

-

Yes

-

-

Header extension table (11.1)

-

-

-

-

Yes

Yes

Yes

Yes

 

 

Routines and Instructions

 

V1

V2

V3

V4

V5

V6

V7

V8

Entry point (5.4, 5.5, 11.1)

Byte address of instruction

Byte address of instruction

Byte address of instruction

Byte address of instruction

Byte address of instruction

Packed address of routine

Byte address of instruction

Byte address of instruction

EXT opcode format (4.3)

-

-

-

-

Yes

Yes

Yes

Yes

Initial local variable values in routine header (5.2.1)

Yes

Yes

Yes

Yes

-

-

-

-

Maximum routine arguments (6.4.1)

3

3

3

7[‡]

7

7

7

7

@aread

-

-

-

-

Yes

Yes

Yes

Yes

@art_shift

-

-

-

-

Yes

Yes

Yes

Yes

@buffer_mode

-

-

-

Yes

Yes

Yes

Yes

Yes

@call

Yes

Yes

Yes

-

-

-

-

-

@call_1n

-

-

-

-

Yes

Yes

Yes

Yes

@call_1s

-

-

-

Yes

Yes

Yes

Yes

Yes

@call_2n

-

-

-

-

Yes

Yes

Yes

Yes

@call_2s

-

-

-

Yes

Yes

Yes

Yes

Yes

@call_vn

-

-

-

-

Yes

Yes

Yes

Yes

@call_vn2

-

-

-

-

Yes

Yes

Yes

Yes

@call_vs

-

-

-

Yes

Yes

Yes

Yes

Yes

@call_vs2

-

-

-

Yes

Yes

Yes

Yes

Yes

@catch

-

-

-

-

Yes

Yes

Yes

Yes

@check_arg_count

-

-

-

-

Yes

Yes

Yes

Yes

@check_unicode

-

-

-

-

Yes

Yes

Yes

Yes

@copy_table

-

-

-

-

Yes

Yes

Yes

Yes

@draw_picture

-

-

-

-

-

Yes

-

-

@encode_text

-

-

-

-

Yes

Yes

Yes

Yes

@erase_line

-

-

-

Yes, operand must be 1

Yes, operand must be 1

Yes, operand is number of pixels

Yes, operand must be 1

Yes, operand must be 1

@erase_picture

-

-

-

-

-

Yes

-

-

@erase_window

-

-

-

Yes

Yes

Yes

Yes

Yes

@get_cursor

-

-

-

Yes

Yes

Yes

Yes

Yes

@get_wind_prop

-

-

-

-

-

Yes

-

-

@input_stream

-

-

Yes

Yes

Yes

Yes

Yes

Yes

@log_shift

-

-

-

-

Yes

Yes

Yes

Yes

@make_menu

-

-

-

-

-

Yes

-

-

@mouse_window

-

-

-

-

-

Yes

-

-

@move_window

-

-

-

-

-

Yes

-

-

@not

1OP:143

1OP:143

1OP:143

1OP:143

VAR:248

VAR:248

VAR:248

VAR:248

@output_stream

-

-

Yes

Yes

Yes, with optional 2nd operand

Yes, with optional 2nd and 3rd operands

Yes, with optional 2nd operand

Yes, with optional 2nd operand

@picture_data

-

-

-

-

-

Yes

-

-

@picture_table

-

-

-

-

-

Yes

-

-

@piracy

-

-

-

-

Yes

Yes

Yes

Yes

@pop

Yes

Yes

Yes

Yes

-

-

-

-

@pop_stack

-

-

-

-

-

Yes

-

-

@print_form

-

-

-

-

-

Yes

-

-

@print_table

-

-

-

-

Yes

Yes

Yes

Yes

@print_unicode

-

-

-

-

Yes

Yes

Yes

Yes

@pull

Yes

Yes

Yes

Yes

Yes

Yes, with optional operand

Yes

Yes

@push_stack

-

-

-

-

-

Yes

-

-

@put_wind_prop

-

-

-

-

-

Yes

-

-

@read_char

-

-

-

Yes

Yes

Yes

Yes

Yes

@read_mouse

-

-

-

-

-

Yes

-

-

@restore

0OP:182, branches

0OP:182, branches

0OP:182, branches

0OP:182, stores

EXT:1, stores, 3 optional operands

EXT:1, stores, 3 optional operands

EXT:1, stores, 3 optional operands

EXT:1, stores, 3 optional operands

@restore_undo

-

-

-

-

Yes

Yes

Yes

Yes

@save

0OP:181, branches

0OP:181, branches

0OP:181, branches

0OP:181, stores

EXT:0, stores, 3 optional operands

EXT:0, stores, 3 optional operands

EXT:0, stores, 3 optional operands

EXT:0, stores, 3 optional operands

@save_undo

-

-

-

-

Yes

Yes

Yes

Yes

@scan_table

-

-

-

Yes

Yes

Yes

Yes

Yes

@scroll_window

-

-

-

-

-

Yes

-

-

@set_colour

-

-

-

-

Yes

Yes, with optional 3rd operand

Yes

Yes

@set_cursor

-

-

-

Yes

Yes

Yes, with optional 3rd argument

Yes

Yes

@set_font

-

-

-

-

Yes

Yes

Yes

Yes

@set_margins

-

-

-

-

-

Yes

-

-

@set_text_style

-

-

-

Yes

Yes

Yes

Yes

Yes

@set_window

-

-

Yes

Yes

Yes

Yes

Yes

Yes

@show_status

-

-

Yes

No effect

No effect

No effect

No effect

No effect

@sound_effect

-

-

Yes

Yes

Yes

Yes

Yes

Yes

@split_window

-

-

Yes

Yes

Yes

Yes

Yes

Yes

@sread

Yes

Yes

Yes

Yes, with optional 3rd and 4th operands

-

-

-

-

@throw

-

-

-

-

Yes

Yes

Yes

Yes

@tokenise

-

-

-

-

Yes

Yes

Yes

Yes

@verify

-

-

Yes

Yes

Yes

Yes

Yes

Yes

@window_size

-

-

-

-

-

Yes

-

-

@window_style

-

-

-

-

-

Yes

-

-

 


[*] The maximum length for V7 is given as 320 KB in Standard 1.0, but corrected to 512 KB in 1.1.

[†] Applies to all windows in V6.

[‡] 6.4.1 incorrectly lists the maximum number of routine arguments in V4 as 3, but in fact V4 has the @call_vs2 opcode, which allows 7.