M68K Trap Tasks

Displays D1.W characters of the string at (A1), at most 255, stopping early at a NUL, then a new line. See task 13 for the NUL terminated form.

Displays D1.W characters of the string at (A1), at most 255, stopping early at a NUL, without a new line. See task 14 for the NUL terminated form.

Reads a line ended with Enter from the current input source; a testcase supplies its next scripted input. Stores the first 79 characters followed by a NUL (zero byte), dropping any additional characters. Text is converted to Windows-1252; a character it cannot represent is stored as ?.

Displays D1.L in decimal, in the smallest field it fits. See tasks 15 and 20.

Reads a line ended with Enter from the current input source, keeping its first 79 characters and dropping the rest. Skips leading whitespace, reads an optional sign, then takes decimal digits up to the first other character. 12abc is 12, and a line with no number, an empty one included, is 0, never an error.

Reads one key from the current input source as soon as it is typed, without waiting for Enter. Enter is $0D. Check task 7 first to poll instead of waiting.

Displays one character.

Ends the program.

The text cursor is where printed text lands, in character cells counted from the top left. Clearing with $FF00 clears text and graphics together, since they share one image, and homes the cursor. Positions outside the screen are clamped to it. All three operations select screen input.

Whether input read by tasks 2, 4, 5 and 18 is echoed in the console and on the screen. With echo off, a line read still moves to a new line when Enter ends it, and a key read shows nothing. Echo is on when a program starts, and Undo restores the previous setting.

Displays the NUL terminated string at (A1), then a new line.

Displays the NUL terminated string at (A1) without a new line.

Displays D1.L as an unsigned number in the base in D2.B, using upper case digits past 9: 255 in base 16 is FF.

Controls the prompt shown while input is waiting and whether a key read of Enter adds a line feed. The waiting prompt appears as a caret and question in the console; the screen does not draw a flashing cursor. Without the line feed, Enter takes the screen text cursor back to the start of its line. Line and number reads always start a new line when Enter ends them, even with echo or line-feed settings off. Both settings are on when a program starts, and Undo restores the previous setting.

Task 14 then task 3: the NUL terminated string, then the signed number.

Task 14 then task 4: the NUL terminated string as a prompt, then a number from the current input source. The input limit and parsing rules of task 4 apply.

Task 3 right justified in a field D2.B columns wide. D2.B is signed, and a negative width left justifies the number in a field that wide instead. A number too long for the field is displayed in full.

Resizes the screen and clears it. The minimum is 640 by 480, which is also the size a program starts with. Windowed and full-screen requests are accepted and ignored because the screen is an editor panel.

The color lines, outlines, pixels and text are drawn in.

The color the insides of rectangles and ellipses and a flood fill are drawn in.

One pixel in the pen color. The pen width does not apply and the drawing point does not move.

Reads the pixel of the image being drawn on, which with double buffering is the off screen one. Outside the screen it answers with the background color.

A line in the pen color, leaving the drawing point at X2, Y2.

A line in the pen color from the drawing point to X, Y, which becomes the new drawing point: a polyline is one task per point.

Moves the drawing point without drawing.

Filled with the fill color and outlined with the pen. The right and bottom edges are excluded, so a rectangle whose edges meet draws nothing.

The ellipse inscribed in that rectangle, filled with the fill color and outlined with the pen. A square bounding rectangle draws a circle.

Spreads the fill color from X, Y over every neighbouring pixel of the color that was there, four ways.

The outline of task 87 in the pen color, with nothing inside.

The outline of task 88 in the pen color, with nothing inside.

Mode 4 draws normally and is the default; mode 2 moves the drawing point without changing any pixel; mode 16 turns double buffering off and mode 17 turns it on, so drawing goes to an off screen image until task 94 shows it.

The width of lines and of the outlines of rectangles and ellipses. A single pixel (task 82) ignores it.

Shows the off screen image drawn under mode 17. With double buffering off it does nothing but ask for a repaint.

Draws the string in the pen color with its top left corner at X, Y, over whatever is already there, so a label can sit on a drawing. Control characters are ignored. The encoding and fixed font described under Text I/O apply. Text printed with the text tasks lands at the text cursor instead (task 11).

Where the next line-to would start.

Selects screen input and polls without consuming anything: the character it reports is the one task 5 or task 2 reads next. A testcase reports its remaining scripted input the same way.

Reads the current state of up to four keys, returning one byte per key in the request order. A key is held from its press until its release, so a tap between two reads can be missed. With D1.L = 0, returns the most recently released and pressed key codes. Each code remains until a newer event replaces it. A key IRQ handler reads this same state. Pending requests can merge, so the codes do not identify a separate event for each IRQ. This task does not provide an event queue.

Accepted and ignored: the screen panel already hands every key it takes to the program, so there are no simulator shortcuts to give up.

The pointer position is in screen pixels with the same origin drawing uses, whatever the panel’s zoom. The release and press states persist until the next one, so a program that polls slowly still sees every click; the double bit is only ever set on a press.

Returns hundredths of a second since local midnight. The value wraps at midnight.

Lets D1.L hundredths of a second of program time pass. The editor stays responsive throughout, and the screen is repainted, so this is how an animation paces itself.

Sets the cycle counter to 0, so it counts again from the next instruction. Undo puts back the count it cleared.

Reads the counter without changing it. Counts follow the selected processor: 68000 by default, 68010 for opt p=68010, and estimates for opt p=68020 or bit-field instructions enabled by opt bit. The instruction selecting task 31 runs before the read and is included: moveq #31, d0 takes 4 cycles and move.b #31, d0 takes 8 on the 68000 and 68010; on the 68020 they take 2 and 4. The trap #15 task itself adds no cycles. See the worked measurement.

D1.B selects the operation:

For operation 6, D2.B = $81 to $87 configures the timer for level 1 to 7. For example, $82 requests a level-2 IRQ every D3.L milliseconds. A positive interval enables the timer; an interval of 0 leaves it off. Setting a new interval replaces the previous interval for that level. D2.B = 1 to 7 turns that level’s timer off, and D2.B = 0 turns every timer off. Other selector values do nothing.

A level holds only one pending IRQ. Multiple elapsed firings merge while a request remains pending, so a handler counter counts delivered requests rather than every elapsed interval. Turning the timer off does not clear a pending request. See the complete timer example for handler installation, configuration and stop.

Assigns an IRQ level to each selected mouse event on the screen panel. For example, move.w #$0301, d1 followed by this task requests level 3 on button presses. Level 0 disables IRQs for the selected events. Events whose bits are clear keep their existing settings; a level above 7 leaves every setting unchanged. Install the level’s autovector before enabling it. The handler can use task 61 to read mouse coordinates and button state. Requests at the same level merge while pending; they do not form an event queue.

Assigns an IRQ level to each selected key event on the focused screen panel. For example, move.w #$0501, d1 followed by this task requests level 5 on key presses. Level 0 disables IRQs for the selected events. Events whose bits are clear keep their existing settings; a level above 7 leaves every setting unchanged. Install the level’s autovector before enabling it. The handler can use task 19 with D1.L = 0 to read the last key pressed and the last key released. Requests at the same level merge while pending, so this does not provide a queue of every key event.

Closes every file the program has open.

Opens the existing file at the path at its start. D0.W is 0 when it opens for reading and writing, or 3 when it opens for reading only. A path with no file, a folder, or a ninth open file is an error.

Creates the file at the path, or empties the one that is there, and opens it for reading and writing. The folders on its path are created with it.

Reads up to D2.L bytes from the file’s position into the buffer, and moves the position past them. Fewer bytes than asked for is a success, with their count in D2.L; none at all is the end of the file, which leaves D2.L as it was.

Writes the D2.L bytes at (A1) at the file’s position, growing the file as needed, and moves the position past them. A write of no bytes, and one to a file opened for reading only, report 2.

Moves the file’s position to D2.L bytes from its start. A position past the end reads as the end of the file until a write there fills the gap with zeros; a negative one is an error.

Closes the file, so that its number can be given to the next one opened.

Removes the file at the path. A file the program still has open stays readable and writable through its number until it is closed.

Asks for the path of a file, for the program to open with task 51 or create with task 52. Cancel, or an empty answer, leaves (A3) alone and puts 0 in D1.L. A testcase answers it with its next scripted input.

Whether there is a file at the path. A folder is not one, so it answers 2.

Plays the WAV file at the path once on the standard player. If it is busy, nothing starts and D0.W is 0; a program that needs playback must try again later. A missing path leaves D0 unchanged, so checking only for zero does not detect every failure.

Loads the file into a standard-player slot for task 72 or 76, and returns no value. An existing but unplayable file is stored anyway; playing that slot returns 0. If the path does not exist, the slot is unchanged.

Plays the file loaded by task 71 once on the standard player. An empty slot leaves D0 unchanged, so checking only for zero does not detect every failure.

Plays the WAV or MIDI file once on the DirectX player, mixed with any other sounds already playing.

Loads the WAV or MIDI file into a DirectX-player slot for task 75 or 77. An existing but unplayable file empties the slot. If the path does not exist, the slot is unchanged.

Plays the file loaded by task 74 once, mixed with any other sounds already playing.

Controls the standard player using a slot loaded by task 71. Controls 0 and 1 play once or loop; they cannot start playback while the player is busy.

Control 2 stops the player only if the supplied slot is nonempty and is the last nonempty slot requested by task 72 or by control 0 or 1 of task 76. That slot selection changes even if the play request fails or the player is busy, so it can differ from the slot actually playing. Control 3 stops the player regardless of the supplied slot. A loop continues until stopped or the program ends.

Controls the DirectX player using a slot loaded by task 74. Controls 0 and 1 play once or loop, mixed with any other sounds already playing. Control 2 stops every sound started from the supplied nonempty slot. Control 3 stops every DirectX sound, including sounds started directly from a file by task 73. A loop continues until stopped or the program ends.