Memory Limits
| Property (Std §) | 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
| Feature (Std §) | V1 | V2 | V3 | V4 | V5 | V6 | V7 | V8 |
|---|---|---|---|---|---|---|---|---|
| Shift lock characters 3.2.2 3.2.3 3.7 | 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 3.7 | Yes | Yes | — | — | — | — | — | — |
I/O
| Capability (Std §) | 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 | 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
| Feature (Std §) | 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
| Field (Std §) | 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 | Yes | — |
| Output stream 3 total width written to header 11.1 | — | — | — | — | — | Yes | — | — |
| Header extension table 11.1 | — | — | — | — | Yes | Yes | Yes | Yes |
Routines & Instructions
Opcodes are listed where they first appear or change behavior. See the Standards Document for full opcode semantics.
| Item (Std §) | 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 | — | — |
Footnotes
- * The maximum length for V7 is given as 320 KB in Standard 1.0, but corrected to 512 KB in Standard 1.1.
- † Applies to all windows in V6.
- ‡ §6.4.1 incorrectly lists the maximum number of routine
arguments in V4 as 3, but V4 has the
@call_vs2opcode, allowing 7.