Psion Series 3a

The Psion Series 3 and 3a were clamshell handheld organizers from the early 1990s. With their black and white screens, Qwerty keyboards and convenient size, they could run for many hours on a pair of AA batteries and were some of the finest 'portable computers' ever released (In my opinion!)

Although they resembled the later ARM handheld pc's, the PSIONs actually ran on 100% 8086 compatible processors, In fact, there is an official DOS based simulator for development!

Here is a comparison between the original Series 3, and the improved 3a, it's the 3a we'll be focusing on in these tutorials!

	Series 3	Series 3a
Cpu	NEC V30H 3.84mhz	NEC V30H 7.68mhz
Display	240x80 2 color (Black,White)	480x160 3 color (Black,White,Grey)
Ram	128k / 256k	256k / 512k / 1mb /2mb
Sound	Piezo buzzer	Speaker / Microphone

Resources

Psion SDK and Manuals - Get these! You'll need them!
Psionics Files - Some unofficial documents which really help with ASM coding!
My WServer.txt - WSERVER in the Psionics Files had some omissions to the correct registers to use with some system calls, which I've attempted to fill by disassembling samples compiled with the C++ SDK

IMG Header

IMG files are similar to EXE files, but not the same!

We can 'Chop up' and EXE and use it to build a valid IMG, or create one from scratch

Offset	Bytes	Sample	Meaning
0	16	'ImageFileType**',0	Fixed string
16	2	0x200F	Image Format Version
18	2	0x0040	Offset in the file to the program code
20	2	0x????	Size of the Program Code
22	2	0x0040	Exec address
24	2	0x0100	Stack Size (in blocks of 16 bytes)
26	2	0x????	Static Data Size (in blocks of 16 bytes)
28	2	0x0100	Heap Size (in blocks of 16 bytes)
30	2	0x????	Static Data Size (in bytes)
32	2	0x????	Checksum of the Program Code
34	2	0x????	Checksum of the Static Data
36	2	0x200C	Program Version Number
38	2	0x0080	Program Priority (usually 128)
40	2	0x0000	Offset in the file to included file 1
42	2	0x0000	Length of included file 1
44	2	0x0000	Offset in the file to included file 2
46	2	0x0000	Length of included file 2
48	2	0x0000	Offset in the file to included file 3
50	2	0x0000	Length of included file 3
52	2	0x0000	Offset in the file to included file 4
54	2	0x0000	Length of included file 4
56	2	0x0000	Number of DLYs within the file (Relocations)
48	4	0x00000000	Offset within the file to the DYL table
62	2	0x0000	Unused

Interrupts with no subfunction

INT #	Name	Description
$8F	GenDataSegment	This call is only useful in assembler code; it sets ES to point to the start of the kernel data space (accessible in OPL using GenGetOsData).
$90	ProcPanic	Panic the current process; this call never returns.
$91	ProcCopyFromById	Copy a number of bytes from the indicated process to the current process.
$92	ProcCopyToById	Copies a number of bytes from the current process to the indicated process.
$93	CharIsDigit
$94	CharIsHexDigit
$95	CharIsPrintable
$96	CharIsAlphabetic
$97	CharIsAlphaNumeric
$98	CharIsUpperCase
$99	CharIsLowerCase
$9A	CharIsSpace
$9B	CharIsPunctuation
$9C	CharIsGraphic
$9D	CharIsControl	Tests to see whether the character has the indicated property. These functions are language dependent.
$9E	CharToUpperChar
$9F	CharToLowerChar
$A0	CharToFoldedChar	Converts two characters to uppercase, lowercase, or folded (uppercase with no accents). These functions are language dependent.
$A1	BufferCopy	Copies a number of bytes from one buffer to another. The case of the buffers overlapping is handled correctly.
$A2	BufferSwap	Swaps the contents of two buffers. The case of the buffers overlapping is handled correctly.
$A3	BufferCompare
$A4	BufferCompareFolded	The contents of the two buffers are compared byte-for-byte, using unsigned comparisons, and the result flags set accordingly.
$A5	BufferMatch
$A6	BufferMatchFolded	The buffer is examined to determine whether it matches the pattern (using the usual wildcards); the call fails if it does not.
$A7	BufferLocate
$A8	BufferLocateFolded	The buffer is searched to determine if the character occurs within it; the call fails if it does not.
$A9	BufferSubBuffer
$AA	BufferSubBufferFolded	Buffer 1 is searched to determine if buffer 2 occurs within it; the call fails if it does not.
$AB	BufferJustify	Buffer 1 is copied into buffer 2, and the remaining space filled with the fill character according to the control code
$AC	StringCopy
$AD	StringCopyFolded	The cstr is copied into the buffer. StringCopyFolded passes each character through CharToFoldedChar during the copy.
$AE	StringConvertToFolded	Each character of the cstr is passed through CharToFoldedChar.
$AF	StringCompare
$B0	StringCompareFolded	The contents of the two cstrs are compared byte-for-byte, using unsigned comparisons, and the result flags set accordingly.
$B1	StringMatch
$B2	StringMatchFolded	The cstr is searched to determine if the pattern occurs within it (using the usual wildcards); the call fails if it does not.
$B3	StringLocate
$B4	StringLocateFolded
$B5	StringLocateInReverse
$B6	StringLocateInReverseFolded	The cstr is searched to determine if the character occurs within it; the call fails if it does not.
$B7	StringSubString
$B8	StringSubStringFolded	Cstr 1 is searched to determine if cstr 2 occurs within it; the call fails if it does not.
$B9	StringLength	Returns the length of a cstr, excluding the terminating zero byte.
$BA	StringValidateName	The cstr is checked to see if it a valid name, and the call fails if it is not.
$BB	LongIntCompare	Compares P and Q (both signed longs) and sets the result flags accordingly.
$BC	LongIntMultiply	Multiples P and Q (both signed longs); the call fails if the result cannot be represented as a signed long.
$BD	LongIntDivide	Divides P by Q (both signed longs); the call fails if Q is zero. The remainder will have the same sign as P.
$BE	LongUnsignedIntCompare	Compares P and Q (both unsigned longs) and sets the result flags accordingly.
$BF	LongUnsignedIntMultiply	Multiples P and Q (both unsigned longs); the call fails if the result cannot be represented as a unsigned long.
$C0	LongUnsignedIntDivide	Divides P by Q (both unsigned longs); the call fails if Q is zero.
$C1	FloatAdd	Calculates the specified one of P+Q, P-Q, P*Q, or P/Q, and places the result in P. Both P and Q are reals.
$C2	FloatSubtract	Calculates the specified one of P+Q, P-Q, P*Q, or P/Q, and places the result in P. Both P and Q are reals.
$C3	FloatMultiply	Calculates the specified one of P+Q, P-Q, P*Q, or P/Q, and places the result in P. Both P and Q are reals.
$C4	FloatDivide	Calculates the specified one of P+Q, P-Q, P*Q, or P/Q, and places the result in P. Both P and Q are reals.
$C5	FloatCompare	Compares two reals and sets the result flags appropriately.
$C6	FloatNegate	Negates a real in-situ.
$C7	FloatToInt
$C8	FloatToUnsignedInt	Converts a real to a signed or unsigned int; the call fails if the result is out of range. FloatToUnsignedInt ignores the sign of the real.
$C9	FloatToLong
$CA	FloatToUnsignedLong	Converts a real to a signed or unsigned long; the call fails if the result is out of range.
$CB	IntToFloat
$CC	UnsignedIntToFloat	Converts a signed or unsigned int to a real.
$CD	LongToFloat
$CE	UnsignedLongToFloat	Converts a signed or unsigned long to a real.
$CF	LibSend
$D0	LibSendSuper	These functions send a message to an object and invoke a method on that object.
$D4	Dummy	This function has no effect.
$D5	GenIntByNumber	This call is equivalent to the OS keyword; it calls another system call with the arguments and results stored in 12 byte blocks.
$D9	LibEnterSend	This is identical to LibSend, except that it also starts a new "entry-exit region". The method description will state when this is needed.
$DA	IoKeyAndMouseStatus
$DB	StringCapitalise	The first character of the cstr is passed through CharToUpperChar, and the remaining characters through CharToLowerChar.
$DC	ProcIndStringCopyFromById	This copies a cstr from the indicated process to the current process.
$DE	IoSerManager

Window Interrupts

INT $8D AH=#	Name	Description
$00	wEndRedraw	Ends redrawing, as started by wBeginRedrawWin or related calls.
$01	wEraseTextCursor	Makes the text cursor invisible.
$02	wReleaseMouse	Cancels any call to wCaptureMouse.
$03	gFreeTempGC	Destroys the temporary graphics context, and makes the remembered current graphics context be current again.
$04	wCancel
$85	wDisconnect
$06	wDetachClient	Detaches the client from any process it is attached to (see wAttachToClient) and moves it to the back.
$07	wCleanUp	Returns the window server to a standard state. This frees any temporary graphics context, ends any redraws taking place
$08	wAttachToForegroundClient	Attaches the client to the current foreground client, if different. See wAttachToClient for details.
$09	wUserMsg	Instructs the window server to send the client a WM_USER_MSG event when there are no other events to deliver.
$8A	wStartCompute	Inform the window server that the client is about to start intensive computation, and its priority should be set to 112 (background) even if it is in the foreground.
$8B	wEndCompute	Cancel the effect of wStartCompute; if the client is in the foreground, sets its priority back to 128 (foreground).
$8C	wClientInfo	Returns information about a process
$0D	wCloseWindowTree	Destroys the window and all its descendants.
$8E	wInquireWindow	The first 10 bytes of the block are set to the flags, position, and size of the specified window.
$0F	wCaptureMouse	Captures the mouse within the window and its descendants.
$10	wBeginRedrawWin	Validate the window for redrawing. Validation causes all pixels to be set or cleared if the background mode is 1 or 2
$11	wFree	Destroy an object and free all the related resources.
$12	wMakeInvisible	The window is marked as invisible; a window will not appear on the screen if it or any of its ancestors is invisible.
$93	wAttachtoClient	Attaches the current process to the specified one.
$14	wInitialiseWindowTree	The specified window and its descendants are initialized.
$15	wInvalidateWin	Add the entire window to its own update region. This will cause a redraw event
$16	wValidateWin	Validate the window - causing all pixels to be set or cleared if the background mode is 1 or 2
$17	wMakeVisible	Cancels wMakeInvisible on the window.
$18	wClientIconised	Iconises or deiconises the current process. Iconisation only works on large screen systems.
$19	wClientPosition	Move the specified process (zero means the current process) to the given position in the window server task list.
$9A	wInquireWindowOffset	The buffer is filled in with the position of window B relative to window A
$1B	wWindowPosition	Moves the window to the specified position within the sibling list (the list of windows with the same parent).
$1C	wScrollRect	The pixels defined by the rectangle are copied to a new rectangle offset by the indicated distance.
$1D	wRubberBand	Starts rubber banding, with the rubber band limited to the specified window or allowed to roam over the screen.
$1E	gCopyRect	Copies a rectangular block from one part of a bitmap to another (the current graphics context should refer to a bitmap).
$9F	gPeekBit	Copies a horizontal row of pixels into the buffer. The point definition block gives the first pixel to be copied
$20	gDrawPolyLine	Draws a sequence of lines according to the control block
$21	gFillPattern	Fills the specified rectangle with copies of the bitmap.
$22	gCreateTempGC	Creates a new temporary graphics context associated with the window or bitmap, and makes it the current GC.
$A3	gCreateGC	Creates a new graphics context associated with the window or bitmap, and makes it the current GC.
$24	gSetGC	Makes the specified graphics context current, and modifies those properties specified in the selector mask.
$25	wSetWindow	Changes various properties of a window.
$26	wBeginRedrawWinGC	Validate the window for redrawing (see wBeginRedrawWin) but using a temporary graphics context.
$27	gDrawLine	Draws a line between the two locations. If horizontal or vertical, the line includes the end with the lower coordinates.
$28	gPrintText	Prints the string at the indicated location.
$29	gCopyBit	Copies a rectangular block from a bitmap or a backed-up window (see gSaveBit).
$AA	wCreateWindow	Creates a new window which is a child of the specified window, and gives it the indicated id and handle
$2B	wBeginRedrawGC	Validate the window for redrawing (see wBeginRedrawWin) with the update region set to the indicated rectangle
$AC	gPrintClipText	Prints the string at the indicated location as gPrintText, but only enough characters are printed to fit within the specified number of pixels.
$2D	gPrintBoxText	Clears the specified rectangle, then prints the string within it using text mode 0 (set pixels).
$AE	gOpenBit	Loads a specified bitmap from a file.
$AF	gOpenMouseIcon	Loads a specified mouse icon from a file.
$B0	gOpenFont	Opens the specified font file.
$31	gDrawBox	Draws a box of the appropriate size.
$B2	wLoadDYL	Load a DYL into the window server. The DYL must already have been loaded into memory
$B3	gCreateBit	Creates an uninitialized writeable bitmap.
$34	wScrollWin	Identical to wScrollRect with the rectangle structure set to (0, 0, width, height).
$35	wDrawTextCursor	As wTextCursor, but the properties byte is ignored and treated as zero.
$36	wInvalidateRect	Add the rectangle to the update region of the window. This will generate a redraw event if necessary.
$37	wBeginRedraw	Validate the window for redrawing (see wBeginRedrawWin) with the update region set to the rectangle.
$38	wValidateRect	Validate the indicated rectangle of the window - causing all pixels to be set or cleared if the background mode is 1 or 2
$B9	gSaveBit	Writes a bitmap to the named file. A window identifier must be for a window with a background redraw method of 3, in which case its off-screen bitmap is used.
$3A	gClrRect	Sets, clears, or inverts all pixels in the specified rectangle.
$3B	wCallDYL	Call a function in a DYL loaded into the window server that has no result.
$BC	wCallDYLreply	Call a function in a DYL loaded into the window server that has a result.
$BD	wSetWinBitmap	Attaches an animated sequence of bitmaps to the background of a window.
$3E	wChangeWinBitmap	Replace the appropriate bitmap in a sequence (see wSetWinBitmap) with the new information in the block.
$BF	wEscapeon
$40	RConnect
$C1	wEscapeoff
$C2	wGetWindowPosition v3	Returns the position of the window in its sibling list (the windows with the same parent).
$C3	gSaveRect	Saves a rectangle from a bitmap, backed-up window, or the screen (see gSaveBit for details).
$44	wReassignRootWindow	All future calls within this client will treat the specified window as it it were the whole screen
$C5	wCaptureKey v3	Captures certain key combinations; from now on, these key presses will be sent to this client whether or not it is in the foreground.
$C6	wCancelCaptureKey v3	Cancels a call to wCaptureKey with identical arguments.
$47	wSystemModal v3	Makes the current client system modal and sets its position in the task list.
$48	wCancelSystemModal v3	Cancels a call to wSystemModal and re-positions the client.
$49	gBorder v3 cgc	Draws a border just inside the window or bitmap of the current graphics context.
$4A	gBorderRect v3 cgc	Draws a border just inside the indicated rectangle. The border type is as for gBorder.
$4B	gXPrintText v3 cgc	Prints the text, as gPrintText in mode 4 (copy with background), but with embellishments
$4C	gInvObloid v3 cgc	Inverts all the pixels, except the four corner pixels, of the rectangle specified by the block
$4D	wEnablePauseKey v3	Allows the program to be paused by the user by pressing CTRL-S; this is initially turned on.
$CE	wDisablePauseKey v3	Disallow the program from being paused by the use of CTRL-S.
$4F	wsEnable	Turns on the permanent status window.
$50	wsDisable	Turns off the permanent status window.
$51	wInformOn v3.5	Instructs the window server to send WM_ON events when the client is in the foreground.
$52	wsUpdate	Updates the contents of the status window to reflect a change elsewhere.
$D3	wsCreateClock	Creates a clock. See wsCreateClock2, which includes all the functionality of this call together with additional features.
$54	wsSetClock	Changes the difference between clock and system time for a clock.
$D5	wSetBusyMsg	Waits for the required time (during which another call can cancel the previous request) and then displays the text
$56	wsDisableTemp	Disable the display of a temporary status window via the PSION-MENU keypress.
$57	wsEnableTemp	Enable the display of a temporary status window via the PSION-MENU keypress.
$D8	wSystem	Changes settings within the window server (thus affecting all clients).
$D9	wGetProcessList v3.5	The buffer is filled with a list of all the processes connected to the window server
$DA	wSendCommand v3.5	Sends command data to the specified process. The process will receive a WM_COMMAND event, and should then call wGetCommand.
$DB	wGetCommand v3.5	Reads the last command data sent by wSendCommand into the buffer.
$5C	wTextCursor	Make the text cursor visible if it is not, and move it to the window and location given.
$DD	wAppKeyHandler
$DE	wInfoMsgCorner	Displays the text in the indicated corner for 2 to 2.5 seconds
$5F	gSetOpenAddress	Modifies the next call to any of...
$60	wDrawButton
$E1	wSetTaskKey v3.5	Causes the relevant keypresses (see wCaptureKey) to be treated as the "task key".
$E2	wSetBackTaskKey v3.5	Identical to wSetTaskKey, except that it sets a "reverse task key" which brings the rearmost process to the foreground.
$E3	wCancelTaskKey v3.5	Cancels a previous call to wSetTaskKey with the same arguments.
$E4	wCancelBackTaskKey v3.5	Cancels a previous call to wSetBackTaskKey with the same arguments.
$E5	SwExt
$E6	gOpenFontIndex v4	Opens the specified font from a multiple-font file.
$E7	gInitBit v4	Opens a file containing one or more bitmaps, ready for gGetBit and gDrawBit.
$E8	gGetBit v4	Loads a bitmap from the file given by the handle (which must have been returned by gInitBit).
$E9	gDrawBit v4	Copies a rectangle from a bitmap in a file to the window or bitmap given by the current graphics context.
$EA	gQueryBit v4	The buffer is filled with the size of the specified bitmap
$6B	wsStatusWindow v4	Sets the format of the status window.
$6C	wInformOnAll v4	Instructs the window server to send or not send WM_ON events.
$ED	wsCreateClock2 v4	Creates a clock, which will then tick automatically.
$EE	wSetPriorityControl v4	Sets server-controlled priority handling.
$EF	gConfigureFonts v4	Creates a font group, which is a set of fonts intended for use in various styles
$F0	wInquireStatusWindow v4	The buffer is filled in with the coordinates the status window would have if it had the indicated format
$F1	wInquireCompatibility	Returns the state of the Compatibility mode. See wCompatibilityMode for details.
$F2	gReadFontHeader v4	The font header of the specified font is read into the buffer.
$F3	gReadFontGroupHeader v4	The file must be a multiple font file. The number of fonts is placed in the word at offset 0 of the buffer
$F4	wSetSystemFont v4	Changes the font in use for one of the four standard system fonts.
$F5	wSetSprite v4	Moves the sprite, or change a bitmap set, or both.
$F6	wCreateSprite v4	Attaches an animated sequence of bitmap sets to a window as a sprite; the sprite will appear in front of everything else in the window.
$F7	wsSetList v4	Sets the "mode", or "diamond" list in the status window.
$F8	wsSelectList v4	Sets the position of the diamond in the status window.
$79	gShadowText v4 cgc	Prints the text, ignoring the text mode, but applying shadow and lighting effects according to the information block
$7A	gDrawObject v4 cgc	Draws a special object just inside the specified rectangle.
$7B	gBorder2 v4 cgc	Draws a border as gBorder, except that it can also generate a 3-D effect on screens with grey available.
$7C	gBorder2Rect v4 cgc	Draws a border as gBorderRect, except that it can also generate a 3-D effect on screens with grey available.
$FD	wCompatibilityMode	Changes the compatibility mode state. Off=Normal On=Doublesize
$7E AL $00	wDrawButton2	Draws a button containing a string. Series 3a buttons require the window to have a grey plane.
$7E AL $01	InformInactivity
$7E AL $02	wDisableKeyClick v4	Enables or disables key clicks for the current process.
$FF AL $00	gInitMultiSave v4	Creates a file capable of holding the specified number of bitmaps, for use with gSaveMultiBit and gSaveMultiRect.
$FF AL $01	gSaveMultiBit v4	Saves the specified bitmap as the next bitmap in the multisave file created by gInitMultiSave.
$FF AL $02	gSaveMultiRect v4	Saves a rectangle from the specified bitmap as the next bitmap in the multisave file, as for gSaveMultiBit.
$FF AL $03	gEndMultiSave v4	Closes the multisave file, making it unavailable for further saves.
$FF AL $04	gInquireChecksum v4	Checksums the specified bitmap and writes the checksum to the word pointed to
$FF AL $05	gCreateFontHeader
$FF AL $06	wSupportInfo v4	The buffer is filled in with information about supported features
$??	wsScreenExt	The buffer is filled in with the size of the screen excluding the current status window.

ServFunc Interrupts

INT $D6 AH=#	Name	Description
$00	wConnect	used to connect to the window server.
$01	gPlayback
$02	gCloseMetafile
$03	gRecordToMetafile
$04	wFlush	Sends any buffered commands to the server.
$05	wCloseDown
$06	wSelect
$07	wPanic
$08	wGetEvent	async.
$09	wDisconnect	Disconnects from the window server and frees all associated resources.
$0A	wCheckPoint	Sends any buffered commands to the server (as wFlush) and reports any errors immediately (see wDisableLeaves)
$0B	gTextWidth	Returns the width in pixels of the specified string when displayed in the specified font and style adjustments.
$0C	gFontInfo	Fills the buffer with information about the font modified by the style
$0D	wDisableLeaves	Sets the error handling mechanism used by the window server calls.
$0E	gCheckBitmapID v3	Succeeds (returning 0) if the bitmap identifier is valid. Fails otherwise.
$0F	Alert
$10	AlertCancel
$11	gTextCount
$12	gGetWidthTable	Fills the buffer with the widths of each character in the font as adjusted.
$13	wGetEventSpecial v4	Starts looking asynchronously for an event as wGetEvent, but only accepts events of specific types.
$14	wGetEventUpdate v4	If there is an asynchronous call to wGetEvent or wGetEventSpecial outstanding, it changes the mask specifying the events being looked for.

Segment Interrupts

INT $80 AH=#	Name	Description
$00	SegFreeMemory	Returns the amount of free system memory, in units of 16 bytes.
$01	SegCreate	Creates an additional memory segment. Each segment must be given a name, of the form "8.3" (i.e. up to 8 characters
$02	SegDelete	Deletes an additional memory segment. If any other process has opened the segment, the call will fail.
$03	SegOpen	Opens the additional memory segment with the given name (if no such segment exists, the call will fail).
$04	SegClose	Closes an additional memory segment which the process has open.
$05	SegSize	Returns the size of an additional memory segment in units of 16 bytes.
$06	SegAdjustSize	Changes the size of an additional memory segment. The memory will be added to or removed from the end of the segment.
$07	SegFind	Finds the additional memory segments with names matching the search pattern (use ? and * as wild cards).
$08	SegCopyTo	Copies data from the current process to an additional memory segment.
$09	SegCopyFrom	Copies data from an additional memory segment to the current process.
$0A	SegLock	Locks an additional memory segment; a locked segment will not be deleted even if no processes have it open.
$0B	SegUnLock	Unlocks an additional memory segment. The number of unlock calls should equal the number of lock calls
$0C	SegRamDiskUsed	Returns the size of the ram disc; this should be treated carefully, as it can change without warning.
$0D	SegCloseLockedOrDevice	Unlocks an additional memory segment where the handle may be that for a different process. See SegUnLock for more details.

Heap Interrupts

INT $81 AH=#	Name	Description
$00	HeapAllocateCell	Allocates a block of memory from the heap. The returned block may be larger than requested.
$01	HeapReAllocateCell	Changes the size of a heap block; the block may have to be moved to do this.
$02	HeapAdjustCellSize	Changes the size of a heap block; the block may have to be moved to do this.
$03	HeapFreeCell	Frees a previously allocated heap block.
$04	HeapCellSize	Returns the actual size of a heap block (which may be larger than requested when the block was created or last resized).
$05	HeapFreeMemory	Returns the amount of heap space which can be allocated

Semaphore Interrupts

INT $82 AH=#	Name	Description
$00	SemCreate	Creates a new semaphore for process interlocking. Each semaphore has a list of processes associated with it
$01	SemDelete	Deletes a semaphore. Any processes on the semaphore's list will be restarted.
$02	SemWait	If the value of the semaphore is positive or zero, one is subtracted from it.
$03	SemSignalOnce	If the list for the semaphore is not empty, the first process on the list is removed and restarted.
$04	SemSignalMany	This is equivalent to making several calls to SemSignalOnce.
$05	SemSignalOnceNoReSched	This is identical to SemSignalOnce except that a reschedule never takes place because of the call

Message Interrupts

INT $83 AH=#	Name	Description
$00	MessInit	Initialize the message system so that the current process can receive inter-process messages.
$01	MessReceiveAsynchronous	When a message arrives, the message slot pointer is set to the address of the message
$02	MessReceiveWithWait	When a message arrives (this may have happened before the call; otherwise the call waits until a message arrives)
$03	MessReceiveCancel	Cancel any pending MessReceiveAsynchronous.
$04	MessSend	Send a message to a process. The call will block until there is a free message slot in the receiving process.
$05	MessSendReceiveAsynchronous	Send a message to a process; when the recipient replies, the status word is set to the reply and the process is sent an IOSIGNAL.
$06	MessSendReceiveWithWait	Send a message to a process, and blocks until the recipient replies.
$07	MessFree	The reply is sent to the recipient of the message, and the message slot is freed and can be used for another incoming message.
$08	MessSignal	Requests that, when the specified process terminates, the kernel sends a message of the indicated type to the current process.
$09	MessSignalCancel
$0A	MessSignalCancelX	Cancels a call to MessSignal for the indicated process.

IO Interrupts

INT $85 AH=#	Name	Description
$00	IoOpen	Opens a channel to a device driver.
$06	DevLoadLDD
$07	DevLoadPDD	Loads a device driver into the system. A driver cannot be opened until it is loaded.
$08	DevDelete	Unloads a device driver from the system. Open drivers and those in the ROM cannot be unloaded.
$09	DevQueryUnits	Returns the number of simultaneous open channels supported by a driver (which must be a logical one); $FFFF indicates no limit.
$0A	DevFind	Finds all devices with names matching the search pattern (use ? and * as wild cards).

Dev Interrupts

INT $86 AH=#	Name	Description
$00	IoAsynchronous
$01	IoAsynchronousNoError
$02	IoWithWait	These calls are equivalent to the IOA, IOC, and IOW keywords respectively
$05	IoWaitForSignal	This call is equivalent to the IOWAIT keyword.
$06	IoWaitForStatus	This call is equivalent to the IOWAIT keyword.
$07	IoYield	This call is equivalent to the IOYIELD keyword.
$08	IoSignal	Sends an IOSIGNAL to the current process. This call is equivalent to the IOSIGNAL keyword.
$09	IoSignalByPid
$0A	IoSignalByPidNoReSched	Sends an IOSIGNAL to a process. With the latter call a reschedule never takes place because of the call
$10	IoClose	This call is equivalent to the IOCLOSE keyword.
$11	IoRead	These calls are equivalent to the IOREAD and IOWRITE keywords.
$12	IoWrite	These calls are equivalent to the IOREAD and IOWRITE keywords.
$13	IoSeek	This call is equivalent to the IOSEEK keyword.
$18	IoShiftStates	This call makes available the state of the various modifier keys
$19	IoWaitForSignalNoHandler	This call should be used instead of IOSEEK by tasks (subsidiary processes of a process).
$1A	IoSignalKillAsynchronous	This call completes, and the status word is set to 0, when the specified process terminates.
$1B	IoSignalKillCancel	Cancel any pending IoSignalKillAsynchronous.
$1E	IoPlaySoundW v3	Plays a sound file. A duration of 0 means the file header specifies the duration
$1F	IoPlaySoundA v3	Plays a sound file asynchronously; the call completes when the sound has finished.
$20	IoPlaySoundCancel	Cancel any pending IoPlaySoundA.
$21	IoRecordSoundW v3	Records a sound file. Note that 2048 samples are slightly more than a quarter of a second.
$22	IoRecordSoundA v3	Records a sound file asynchronously; the call completes when the recording has finished.
$23	IoRecordSoundCancel v3	Cancel any pending IoRecordSoundA.
$24	IoPlaySoundAO v3.9	Plays part of a sound file asynchronously, skipping some initial portion of the sound; the call completes when the sound has finished.

File Interrupts

INT $87 AH=#	Name	Description
$00		carried out automatically for OPL programs.
$01	FilExecute	Starts a new process and places it in "suspended" state.
$02	FilParse	This call is equivalent to the PARSE$ keyword.
$03	FilPathGet	The buffer is filled with the current filing system default path (a cstr).
$04	FilPathSet	Sets the default path (equivalent to the SETPATH keyword).
$05	FilPathTest	Equivalent to the EXIST keyword; the call succeeds if the file with that pathname exists.
$06	FilDelete	Equivalent to the DELETE keyword; non-empty directories cannot be deleted.
$07	FilRename	Equivalent to the RENAME keyword.
$08	FilStatusGet	The buffer is filled in with information about the file
$09	FilStatusSet	The attributes indicated in the mask of the specified file are altered to the new values
$0A	FilStatusDevice	The buffer is filled in with information about the device
$0B	FilStatusSystem	The buffer is filled in with information about the node
$0C	FilMakeDirectory	This is equivalent to the MKDIR keyword.
$0D	FilOpenUnique	Open a file with a unique name. This is equivalent to the IOOPEN keyword with a mode of 4.
$0E	FilSystemAttach	The specified physical device driver will be attached to the filing system, possible adding new nodes.
$0F	FilSystemDetach	Detaches a filing system. Built-in filing systems cannot be detached.
$10	FilPathGetById	The buffer is set to the current path of the specified process (a cstr).
$11	FilChangeDirectory	The path name is modified in the requested way.
$13	FilSetFileDate	Sets the modification time of the specified file.
$14	FilLocChanged	Specifies whether any directory in the LOC:: node has changed
$15	FilLocDevice v3	Provides the media type of a device on the LOC:: node (I and M both refer to the internal ramdisc).
$16	FilLocReadPDD v3	Copies data from a device on the LOC:: node to the current process. This call is very efficient, and accesses the raw device.

Proc Interrupts

INT $87 AH=#	Name	Description
$00	ProcId	Gets the process ID of the current process.
$01	ProcIdByName	Gets the process ID of a process whose name matches the pattern (usual wildcards apply, and case is ignored).
$02	ProcGetPriority	Gets the priority of the specified process.
$03	ProcSetPriority	Sets the priority of the specified process.
$05	ProcCreateTask	Tasks are processes which share the data segment of another process. They cannot be conveniently handled in OPL.
$06	ProcResume	Take a process out of the suspended state and start it executing.
$07	ProcSuspend	Place a process in the suspended state.
$08	ProcKill	Kills the specified process, without allowing it to execute any cleanup code.
$09	ProcPanicById	Simulate the specified panic on the specified process.
$0A	ProcNameById	Places the name (a cstr) of the specified process in the buffer.
$0B	ProcFind	Obtains process IDs for processes whose name matches the pattern ("?" and "*" wildcards have their Unix meaning, and case is ignored).
$0C	ProcRename	Rename the specified process; the new name must be between 1 and 8 characters.
$0D	ProcTerminate fails	Terminates the indicated process. The process will be sent a termination message if it has so requested, and will be killed otherwise.
$0E	ProcOnTerminate	When the current process is terminated, it will be sent a message of the specified type; type 0 cancels the request.
$10	ProcGetOwner	Gets the ID of the process owning the specified process (normally the creator of that process).

Time Interrupts

INT $89 AH=#	Name	Description
$00	TimSleepForTenths	Sleep for the specified delay (in units of 0.1 seconds).
$01	TimSleepForTicks	Sleep for the specified delay (in system ticks; there are 32 ticks per second on the Series 3 and 18.2 on the PC emulation).
$02	TimGetSystemTime	Reads the system clock (an abstime).
$03	TimSetSystemTime	Sets the system clock to the given abstime.
$04	TimSystemTimeToDaySeconds	Splits an abstime into a day number and an interval, placed in the buffer
$05	TimDaySecondsToSystemTime	Converts a day number and an interval to an abstime.
$06	TimDaySecondsToDate	Converts a day number and an interval to broken-down time information.
$07	TimDateToDaySeconds	Converts broken-down time to a day number and an interval. The day number in year (offset 6) is ignored.
$08	TimDaysInMonth	Gets the number of days in the specified month (0 = January, 11 = December).
$09	TimDayOfWeek	Gets the day of the week of the given date.
$0A	TimNameOfDay	The buffer is filled with a cstr giving the name of that day of the week.
$0B	TimNameOfMonth	The buffer is filled with a cstr giving the name of that month.
$0C	TimWaitAbsolute	Sleep this process until the specified abstime. If the machine is turned off at that time, it will turn back on.
$0D	TimWeekNumber	Gets the week number of the specified day.
$0E	TimNameOfDayAbb v3	The buffer is filled with a cstr giving the abbreviated name of that day of the week.
$0F	TimNameOfMonthAbb v3	The buffer is filled with a cstr giving the abbreviated name of that month.

Convert Interrupts

INT $8A AH=#	Name	Description
$00	ConvUnsignedIntToBuffer	The value is converted to a string in the specified radix and written to the buffer.
$01	ConvUnsignedLongIntToBuffer	The value is converted to a string, in the same way as ConvUnsignedIntToBuffer.
$02	ConvIntToBuffer	The value is converted to a string in radix 10 and written to the buffer.
$03	ConvLongIntToBuffer	The value is converted to a string in radix 10, as for ConvIntToBuffer.
$04	ConvArgumentsToBuffer	The format is written to the buffer, with certain sequences of characters
$05	ConvStringToUnsignedInt	The string is converted to an unsigned integer in the specified radix.
$06	ConvStringToUnsignedLongInt	The string is converted, in the same manner as ConvStringToUnsignedInt.
$07	ConvStringToInt	The string is converted to an signed integer in radix 10.
$08	ConvStringToLongInt	The string is converted, in the same manner as ConvStringToInt.
$09	ConvFloatToBuffer	The real value is converted to a cstr and placed in the buffer.
$0A	ConvStringToFloat	Converts a string representing a floating-point value and places it in the variable.

Gen Interrupts

INT $8B AH=#	Name	Description
$00	GenVersion	Gets the version of the operating system.
$01	GenLcdType	Gets the display type
$02	GenStartReason	Gets the reason for the last cold start
$03	GenParse	Parse filenames according to certain basic rules. Unlike FilParse, this does not invoke any device drivers.
$04	LongUnsignedIntRandom	Generates a 32 bit unsigned random number from a seed; the number also replaces the seed
$05	GenGetCountryData	Fills the buffer with country-specific data
$06	GenGetErrorText	The buffer will be filled with a cstr giving an error message corresponding to the error number
$07	GenGetOsData	Copy a number of bytes from the kernel workspace to the current process. Within assembler code, this can also be done via GenDataSegment
$09	GenNotify	Sends a message to the notifier process and waits for a reply. The call fails if there is no notifier process running.
$0A	GenNotifyError	This call is equivalent to GenNotify with the second message derived from the error number via GenGetErrorText.
$0D	GenGetRamSizeInParas	Gets the amount of system RAM fitted, in units of 16 bytes.
$0E	GenGetCommandLine	Gets a pointer to the command line if the program was started with program information (see FilExecute).
$0F	GenGetSoundFlags	Gets the sound flags
$10	GenSetSoundFlags	Sets the sound flags to new values (see GenGetSoundFlags).
$11	GenSound	Makes a simple single-frequency note. Access to this call is sequenced
$12	GenMarkActive	These two calls alter the state of the current process to "active" (the default when the process starts) or "non-active".
$13	GenMarkNonActive	These two calls alter the state of the current process to "active" (the default when the process starts) or "non-active".
$14	GenGetText	Copies a message (a cstr) from the kernel message table to the buffer.
$15	GenGetNotifyState	Gets the notify state for the process.
$16	GenSetNotifyState	Sets the notify state for the process. See GenGetNotifyState for details.
$17	GenGetAutoSwitchOffValue	Gets the auto-off time.
$18	GenSetAutoSwitchOffValue	Sets the auto-off time. Times of less than 15 are adjusted to 15.
$1B	GenGetLanguageCode	Gets the current locale code. Locale codes are listed in the Psionics file LOCALES.
$1C	GenGetSuffixes	The buffer is filled with 31 cstrs giving the correct suffix for each of the 31 days of the month.
$1D	GenGetAmPmText	The buffer is filled with a cstr giving the correct suffix for "a.m." or "p.m." times.
$1E	GenSetCountryData	Sets the country-specific data to that in the buffer. See GenGetCountryData for the format of the buffer.
$1F	GenGetBatteryType	The battery type is used to control the warning thresholds.
$20	GenSetBatteryType	Sets the battery type (see GenGetBatteryType).
$21	GenEnvBufferGet	Searches for an environment variable whose name matches the pattern (if there is more than one, which one is chosen is unspecified).
$22	GenEnvBufferSet	Changes the value of the specified enviromment variable, creating it first if necessary. The name may not contain wildcards.
$23	GenEnvBufferDelete	Searches for an environment variable whose name matches the pattern and deletes it
$24	GenEnvBufferFind	Searches for each environment variable whose name matches the pattern.
$25	GenEnvStringGet	Searches for an environment variable whose name matches the pattern
$26	GenEnvStringSet	Changes the value of the specified enviromment variable, creating it first if necessary.
$27	GenEnvStringDelete	Searches for an environment variable whose name matches the pattern and deletes it
$28	GenEnvStringFind	Searches for each environment variable whose name matches the pattern.
$29	GenCrc	Calculates the CCITT Cyclic Redundancy Checksum using the X^16+X^12+X^5+1 polynomial
$2A	GenRomVersion	Gets the version of the system ROM (which includes both the operating system and many files).
$2D	GenAlarmId	Gets the process ID of the alarm server process, or 0 if none is running.
$2E	GenPasswordSet	Sets a new system password. The call will fail and take no action if the current password is incorrect.
$2F	GenPasswordTest	Succeeds if the system password is that provided.
$30	GenPasswordControl	Turns the system password on and off. The call will fail and take no action if the current password is not provided.
$31	GenPasswordQuery	Get the status of the system password.
$32	GenTickle	Resets the auto-off timer. A non-active process (see GenMarkNonActive) can use this to prevent auto-off.
$33	GenSetConfig
$34	GenMaskInit	Initializes an encryption control block according to the password given.
$35	GenMaskEncrypt	Encrypts a block of data according to the encryption control block, which will be updated.
$36	GenMaskDecrypt	Decrypts a block of data according to the encryption control block, which will be updated.
$37	GenSetOnEvents v2.28	Enables or disables reporting of power-on events. By default this is enabled on the Series 3 and disabled on other systems.
$38	GenGetAutoMains v3	Gets the setting of the external power auto-off flag.
$39	GenSetAutoMains v3	Sets the external power auto-off flag.

Float Interrupts

INT $8C AH=#	Name	Description
$00	FloatSin	sine
$01	FloatCos	cosine
$02	FloatTan	tangent
$03	FloatASin	arc sine
$04	FloatACos	arc cosine
$05	FloatATan	arc tangent
$06	FloatExp	exponentiation (base e)
$07	FloatLn	natural logarithm (base e)
$08	FloatLog	decimal logarithm (base 10)
$09	FloatSqrt	Calculates the specified function of the argument.
$0A	FloatPow	Calculates the result of raising the base to the indicated power.
$0B	FloatRand	Generates a random real number based on the unsigned long integer seed, which is unaltered
$0C	FloatMod	Calculates the dividend modulo the divisor, using the formula
$0D	FloatInt	Rounds the argument to the closest integer towards zero (i.e. zeros the fractional part of the argument).

HardW Interrupts

INT $8E AH=#	Name	Description
$11	HwGetSupplyStatus	Gets information about the power supply. The buffer is filled with the following data
$12	HwLcdContrastDelta	Alters the LCD contrast by one step, upwards if AL is between 0 and 127, and downwards if it is between 128 and 255 (all inclusive).
$13	HwReadLcdContrast	Gets the current LCD contrast setting. On a Series 3, only the bottom 4 bits are significant.
$14	HwSwitchOff	Switches the machine off for the specified time, then back on again ($FFFF means never turn back on).
$16	HwExit	Exits the emulation on PC systems; has no effect on actual Psion machines.
$1B	HwGetPsuType	Gets the PSU type: 0 = old MC, 1 = MC "Maxim", 2 = Series 3t, 3 = Series 3a
$1C	HwSupplyWarnings	Gets information about the power supply.
$1D	HwForceSupplyReading
$1E	HwGetBackLight	On systems fitted with a backlight, this value indicates control of the backlight function.
$1F	HwSetBackLight	Sets the backlight control value (see HwGetBackLight).
$20	HwBackLight	Turn Backlight ON/OFF
$22	HwSupplyInfo v3	Fills the buffer with additional information about the power supply
$28	HwGetScanCodes v3	The buffer is filled with information describing the state of each key on the keyboard.
$29	HwGetSsdData
$2A	HwResetBatteryStatus v3.9	The battery status is reset, exactly as if the main batteries had been removed and then replaced.
$2B	HwEnableAutoBatReset v3.9	Enables, disables, or queries the current setting of the automatic reset of the battery status.
$2C	HwGetBatData v3.9	The data is described in the KERNEL file.
$2E	HwReLogPacks v3.9	This has the same effect as opening and then closing the SSD doors.
$2F	HwSetIRPowerLevel v3.9	Sets the IR power level, returning the previous level.
$30	HwReturnTickCount v3.9	Returns a tick count that is incremented 32 times per second.
$31	HwReturnExpansionPortState v3.9	Returns the type and state of the expansion port