GEMDOS Functions
----------------

0x12	WORD	Cauxis()			Check status of standard AUX: input
0x03	WORD	Cauxin()			Read character from standard AUX: input

0x13	WORD	Cauxos()			Check status of standard AUX: output
0x04	void	Cauxout(c)			Write character to standard AUX: output

0x0B	WORD	Cconis()			Check status of standard input
0x01	LONG	Cconin()			Read character from standard input
0x08	LONG	Cnecin()			Read character from standard input, no echo
0x07	LONG	Crawcin()			Raw input from standard input
0x0A	void	Cconrs(buf)			Read edited string from standard input

0x10	WORD	Cconos()			Check status of standard output
0x02	void	Cconout(c)			Write character to standard output
0x09	void	Cconws(str)			Write string to standard output

0x06	LONG	Crawio(w)			Raw I/O to standard input/output

0x11	WORD	Cprnos()			Check status of standard PRN:
0x05	void	Cprnout(c)			Write character to standard PRN:

0x19	WORD	Dgetdrv()			Get default drive
0x0E	LONG	Dsetdrv(drv)			Set default drive
0x36	void	Dfree(buf, drv)			Get drive free space

0x47	void	Dgetpath(buf, drv)		Get current directory
0x3B	WORD	Dsetpath(path)			Set current directory
0x39	WORD	Dcreate(pathname)		Create directory
0x3A	WORD	Ddelete(pathname)		Delete directory
0x43	WORD	Fattrib(fname, wf, atr)		Get / set file attributes
0x57	void	Fdatime(handle, time, wf)	Get / set file timestamp

0x3C	WORD	Fcreate(fname, atr)		Create file
0x41	WORD	Fdelete(fname)			Delete file
0x3D	WORD	Fopen(fname, mode)		Open file
0x3E	WORD	Fclose(handle)			Close file
0x56	WORD	Frename(0, old, new)		Rename file

0x45	WORD	Fdup(handle)			Duplicate file handle
0x46	WORD	Fforce(stdh, nostdh)		Force file handle

0x2F	LONG	Fgetdta()			Get disk transfer address
0x1A	void	Fsetdta(addr)			Set disk transfer address
0x4E	WORD	Fsfirst(fspec, atr)		Search first
0x4F	WORD	Fsnext()			Search next

0x42	LONG	Fseek(offset, handle, mode)	Seek file pointer
0x3F	LONG	Fread(handle, count, buffer)	Read from file
0x40	LONG	Fwrite(handle, count, buffer)	Write to file

0x48	LONG	Malloc(amount)			Allocate memory
0x49	WORD	Mfree(saddr)			Release memory
0x4A	WORD	Mshrink(0, block, newsize)	Shrink size of allocated block

0x4B	WORD	Pexec(mode, ptr1, ptr2, ptr3)	Load / execute process
0x4C	void	Pterm(retcode)			Terminate process with specified exit code
0x00	void	Pterm0()			Terminate process with exit code of 0
0x31	void	Ptermres(keepcnt, retcode)	Terminate and stay resident

0x20	LONG	Super(stack)			Get / set / inquire supervisor mode

0x30	WORD	Sversion()			Get version number

0x2A	WORD	Tgetdate()			Get date
0x2B	WORD	Tsetdate(date)			Set date

0x2C	WORD	Tgettime()			Get time
0x2D	WORD	Tsettime()			Set time

BIOS Error Codes  (-1 .. -31)
-----------------------------

	E_OK		0	No error

	ERROR		-1	Error
	EDRVNR		-2	Drive not ready
	EUNCMD		-3	Unknown command
	E_CRC		-4	CRC error
	EBADRQ		-5	Bad request
	E_SEEK		-6	Seek error
	EMEDIA		-7	Unknown media
	ESECNF		-8	Sector not found
	EPAPER		-9	Out of paper
	EWRITF		-10	Write fault
	EREADF		-11	Read fault
			-12	-unused-
	EWRPRO		-13	Write protect error
	E_CHNG		-14	Media change detected
	EUNDEV		-15	Unknown device
	EBADSF		-16	Bad sectors on format
	EOTHER		-17	Insert other disk (request)

GEMDOS Error Codes  (-32 .. -127)
---------------------------------

	EINVFN		-32	Invalid function number
	EFILNF		-33	File not found
	EPTHNF		-34	Path not found
	ENHNDL		-35	Handle pool exhausted
	EACCDN		-36	Access denied
	EIHNDL		-37	Invalid handle

	ENSMEM		-39	Insufficient memory
	EIMBA		-40	Invalid memory block address

	EDRIVE		-46	Invalid drive specification
	ENMFIL		-47	No more files

	ERANGE		-64	Range error
	EINTRN		-65	GEMDOS internal error
	EPLFMT		-66	Invalid executable file format
	EGSBF		-67	Memory block growth failure

GEMDOS Date Format
------------------

	15:9	years since 1980
	8:5	month  (1..12)
	4:0	day  (1..31)

GEMDOS Time Format
------------------

	15:11	hour  (0..23)
	10:5	minute  (0..59)
	4..0	second / 2  (0..29)

GEMDOS Drive Free Space Format
------------------------------

	+0	number of free clusters
	+4	total number of clusters
	+8	sector size  (in bytes)
	+12	cluster size  (in sectors)

GEMDOS File Attributes
----------------------

	0x01	read only
	0x02	hidden
	0x04	system
	0x08	volume label
	0x10	subdirectory
	0x20	archive

GEMDOS File Search DTA Format
-----------------------------

	+0 .. +20	BYTE	reserved
	+21		BYTE	attribute byte
	+22 .. +23	WORD	time stamp
	+24 .. +25	WORD	date stamp
	+26 .. +29	LONG	file size
	+30 .. +43	BYTE	file name + extension  (null terminated)

GEMDOS File Open Modes
----------------------

	0	read only
	1	write only
	2	read / write

GEMDOS Seek Modes
-----------------

	0	from beginning of file
	1	from current position
	2	from end of file