1 <!doctype linuxdoc system>
5 <!-- Title information -->
8 <author>Maciej Witkowiak, <htmlurl url="mailto:ytm@elysium.pl" name="ytm@elysium.pl">
9 <date>v1.5, 26.12.1999, 2000, 2001, 2002, 2003
11 This is the documentation of cc65's GEOSLib, but information contained here may be also
12 useful for writting GEOS applications in general.
15 <!-- Table of contents -->
18 <!-- Begin the document -->
22 As we all know that the best computers in the world are c64 and c128. They have their GUI too -
23 excellent GEOS. GEOS seems very difficult and cryptic for many people, from programmer's point
24 of view. That's not true. The designers of GEOS created flexible and powerful system, which
25 is easy to use and program.
27 Coding GEOS in C? That's something new. It is possible now - with Ulrich von Bassewitz's cc65
28 package and my GEOSLib you are able to create GEOS applications in no-time.
30 GEOSLib supports a subset of standard cc65 libraries. Whenever possible native Kernal functions
31 are used (e.g. <tt/memset/ is an alias for <tt/FillRam/), however not all are supported. E.g.
32 string functions like <tt/strcmp/, <tt/strcpy/ are doubled with native <tt/CmpString/,
33 <tt/CopyString/ because the latter can handle only 256 byte strings. Keep this in mind when
34 you will write your program. If you don't need long strings simply use functions from Kernal,
35 resulting code will be smaller.
37 <tt/dio/ - direct disk access is available, but you might have problems with devices other
38 than 1541, 1571 or 1581. RAM drives emulating these should work.
40 <tt/conio/ - simple console input-output is available for command line applications.
41 This implementation assumes that one character will fit in 8x8 cell, so output with
42 default BSW font, which is has 9 points, might be a bit messy.
43 <tt/cputs/ will output characters with fixed width, for proportional spacing use
44 <tt/cpputs/ but this function does not update cursor. There is no color support in
45 GEOS 2.0 so color functions are disabled. Both 40 and 80 columns modes are supported
46 and automatically detected.
48 <tt/tgi/ - TGI driver for GEOS that supports both 40 and 80 columns modes but mode can not be
49 changed between <tt/tgi_init/ and <tt/tgi_done/.
51 <tt/joy/ - JOY driver for GEOS supports only joystick, not current pointing device.
53 It is safe to use these standard includes and their contents:
54 <tt/assert.h, conio.h, dio.h, errno.h, em.h, geos.h, joystick.h, modload.h, mouse.h, stdlib.h, string.h, tgi.h, time.h/
56 It was not tested enough, but functions from these includes might work under GEOS:
59 Functions from the headers above are either standard C library functions or cc65-specific, in
60 either case they are not GEOS specific and so they are not described here.
62 I am an assembler programmer and GEOSLib was designed in such way that cc65 could emit the best
63 available code (well, the best as for machine :). Many of the <tt/void foo (void)/ functions are
64 just raw calls to Kernal (assembled just as <tt/jsr _foo/), look in <tt/gsym.h/, where you
65 will find many definitions of standard GEOS locations. Access to these addresses is optimized by
66 cc65 to simple <tt/lda/ and <tt/sta/. Don't be afraid to use C syntax.
70 You will not need c64 or c128 for development. The only hardware requirement is a PC capable of
71 runing cc65. You will however need c64 or c128 emulator and GEOS image disks (.d64) to test your
76 <item><em/cc65/ Excellent package containing C crosscompiler, crossassembler and linker, you
77 can get it from: <htmlurl url="http://www.von-bassewitz.de/uz/cc65/"
78 name="http://www.von-bassewitz.de/uz/cc65/">
79 <item><em/VICE/ This is portable C64, C128 and few other Commodore computers emulator, you
80 can obtain it from: <htmlurl url="http://www.cs.cmu.edu/~dsladic/vice/vice.html"
81 name="http://www.cs.cmu.edu/~dsladic/vice/vice.html">. VICE package contains
82 c1541 program that is able to convert/unconvert GEOS files to disk images.
83 <item><em/Star Commander/ This tool is only for DOS. You will need it for transferring
84 object files from PC to 1541. There's also one important ability of this
85 tool - it automatically un-converts .cvt files into GEOS native format on
87 <item><em/cbm4linux/ A Linux kernel module that allows for communication with 1541 and
88 other Commodore IEC bus drives. It can be replacement for Star Commander if
89 you want only to transfer files to a disk and uncovert using GEOS program for
90 this purpose. Check out: <htmlurl url="http://www.lb.shuttle.de/puffin/cbm4linux/"
91 name="http://www.lb.shuttle.de/puffin/cbm4linux">
94 VICE and cc65 are portable - they run on variety of platforms - DOS, Win32 and UNIX. GEOSLib only
97 <em/Update:/ starting from v2.5.0 GEOSLib is a part of cc65 package as its GEOS support library.
101 I want to thank Uz for his cc65 package, Alexander Boyce for his excellent GEOS Programmer's
102 Reference Guide and BSW for GEOS.
104 GEOSLib is covered by the same license as cc65. You can find the whole text among documentation.
105 I would really appreciate if you would like to send me your comments, suggestions, questions,
106 changes, bug reports etc. I will also appreciate if you will just give me a sign that you are
107 using GEOSLib - not especially something big and important, mail me even if you are just playing
110 You can send postcards with hellos to:
112 Maciej Witkowiak, ul. Slowackiego 6/57, 77-400 ZLOTOW
116 e-mail: <tt/ytm@elysium.pl/
118 <sect>What have you got and what to do with it?
120 This chapter describes some rules you ought to obey, and how to use GEOSLib.
124 Apart from this file, which merely describes only standard GEOS library functions, you should read
125 <tt/grc/ (GEOS resource compiler) documentation. There are informations about necessary resource
126 files (each GEOS application neeeds at least one) and the building process - what should be done
127 and in what order. Please also read cc65's documentation on how to compile C, assembler and link
130 All in all, you just need to place
132 #include <geos.h>
134 on top of your source.
136 As a general rule read the sources of example programs and read the headers. These are the most
137 reliable sources of knowledge ;). You will also find there many C macros representing various
138 arguments passed to functions. Please use them. You will find your sources easier to understand,
139 and it will be easier to find bugs.
141 All types used in GEOSLib are <tt/unsigned/.
143 Screen coordinates are given in pixels unless stated differently.
145 <sect1>Notes on style
147 Contrary to typical GEOS assembly program which has a main function called after loading that
148 setups the screen, menus, icons etc. exiting from <tt/main/ function in C is equivalent to
149 calling <tt/exit()/. These two are the only safe methods of terminating applications. DO NOT
150 USE <tt/EnterDeskTop/! Your data may be lost as library destructors and functions registered
151 with <tt/atexit/ will not be called.
153 For GEOS GUI applications the recommended program structure is to have everything initialized
154 in <tt/main/ function and at the end of it a call to <tt/MainLoop()/ function. WARNING! This
155 function never returns, any code between <tt/MainLoop();/ and the end of <tt/main/ will not
156 be executed. You have to call <tt/exit()/ explicitly somewhere in your code (e.g. in a menu
157 handler or via DialogBox action).
159 Whenever possible use definitions from <tt/gsym.h/. The resulting code is translated by cc65 into
160 series of <tt/lda/ and <tt/sta/, so you can't do it better :-).
162 Don't hesitate to use library functions. Everything was written with size and speed in mind. In
163 fact many calls are just redirections to GEOS kernal which results in simple <tt/jsr/.
165 You might wonder why I have chosen sometimes weird order of arguments in functions. I just
166 wanted to avoid unnecessary pushing and popping arguments from stack because cc65 can pass single
167 <tt/unsigned int/ through CPU registers.
169 Do not try to compile in strict ANSI mode. Library uses cc65 extensions which are not available in
172 It is possible to use dynamicaly loaded modules, three such modules are provided:
173 GEOS TGI driver, GEOS EMD driver (for VDC extended memory) and GEOS JOY driver.
174 Just make sure that their filenames appear UPPERCASE in DeskTop. There are no more special
175 recommendations, read cc65 documentation about modules and demo programs source code.
177 <sect>Library Functions
179 Functions here are sorted more or less in the way they appear in header files. This way I am able
180 to keep functions covering similar task near each other. All function names are identical to those
181 from <tt/geosSym/ file provided with GeoProgrammer package. Only my extensions to <tt/geosSym/
182 are covered by new names, but I tried to keep them in the naming convention.
186 This section covers drawing package of GEOS along with text output routines.
190 <tt/void SetPattern (char pattern)/
192 This function sets current pattern to given. There are 32 different patterns in GEOS. You can
193 see them together in the filling box in GeoPaint.
195 <sect2>GraphicsString
197 <tt/void GraphicsString (char *myGString)/
199 One of the more powerfull routines of GEOS. This function calls other graphic functions depending
200 on given command string. See structures chapter for more detailed description of the structure of it.
202 <sect2>Rectangle functions
204 Parameters to those functions are grouped in <tt/struct window drawWindow/. To speed up things and
205 reduce overhead this structure is glued to zero page locations, where all rectangle functions
206 expect their parameters. You can modify data directly (e.g. <tt/drawWindow.top=10/) or via
207 <tt/InitDrawWindow/ function. Contents of <tt/drawWindow/ are guaranteed not to change only when
208 using graphics functions. In other case you should keep your data in separate <tt/struct window/
209 and use <tt/InitDrawWindow/ before first call to rectangle functions.
211 <sect3>InitDrawWindow
213 <tt/void InitDrawWindow (struct window *myWindow)/
215 This function only copies contents of <tt/myWindow/ into system area of <tt/drawWindow/. Use it
216 if for some reason you have to keep window data out of zero page space.
220 <tt/void Rectangle (void)/
222 This draws on screen rectangle filled with current pattern.
224 <sect3>FrameRectangle
226 <tt/void FrameRectangle (char pattern)/
228 This one draws frame with given bit pattern (not a pattern from GEOS palette).
230 <sect3>InvertRectangle
232 <tt/void InvertRectangle (void)/
234 Just as the name says...
236 <sect3>ImprintRectangle and RecoverRectangle
238 <tt/void ImprintRectangle (void)/
240 <tt/void RecoverRectangle (void)/
242 These two functions are for copying parts of the screen to (<tt/Imprint/) and from (<tt/Recover/)
243 backbuffer of the screen. For example when drawing new menu box GEOS first uses
244 <tt/ImprintRectangle/ to save the area under the box, and restores it by <tt/RecoverRectangle/ upon
247 <sect2>Line Functions
249 GEOS drawing package is optimized so there are different functions for drawing vertical and
252 <sect3>HorizontalLine
254 <tt/void HorizontalLine (char pattern, char y, unsigned xStart, unsigned xEnd)/
256 This function draws horizontal line using given pattern - here it is a true bit pattern, not
257 pattern set by <tt/SetPattern/.
261 <tt/void InvertLine (char y, unsigned xStart, unsigned xEnd)/
263 There is only horizontal version.
267 <tt/void RecoverLine (char y, unsigned xStart, unsigned xEnd)/
269 This function recovers only one line. It is utilized by <tt/RecoverRectangle/. See its description
274 <tt/void VerticalLine (char pattern, char yStart, char yEnd, unsigned x)/
276 This function draws vertical line using given pattern. Note that <tt/pattern/ is not a pattern
277 number as set in <tt/SetPattern/ but a true bit pattern.
281 <tt/void DrawLine (struct window *myWindow)/
283 <tt/top/ parameters of <tt/struct window/ describe the starting point of the line, while
284 <tt/bottom/ are for the ending point. Current pattern from <tt/SetPattern/ is used for drawing.
286 <sect2>Point Functions
288 Parameters to these two functions are passed by a pointer to own <tt/struct pixel/ filled with
293 <tt/void DrawPoint (struct pixel *myPixel)/
295 Draws single point on the screen, no matter what the current pattern is.
299 <tt/char TestPoint (struct pixel *myPixel)/
301 This function tests if given pixel is set and returns <tt/true/ (non-zero) or <tt/false/ (zero).
303 <sect2>Character and string output
307 <tt/cpputsxy (char x, char y, char *myString)/
309 <tt/cpputs (char *myString)/
311 Actually this is a part of <tt/conio/, but this function is non-standard. It is
312 a variety of <tt/cputs/ that will output string with proportional spacing, not
313 fixed like <tt/cputs/.
317 <tt/void PutChar (char character, char y, char x)/
319 This function outputs single character using current style and font to screen.
323 <tt/void PutString (char *myString, char y, unsigned x)/
325 Same as <tt/PutChar/ except the fact that you can output whole <tt/NULL/-terminated string.
326 See <tt/ggraph.h/ for list of tokens that you can also place in the string - like <tt/CBOLDON/ or
331 <tt/void PutDecimal (char parameter, int value, char y, unsigned x)/
333 This function converts <tt/value/ to its decimal representation and outputs it to the screen.
334 Depending on given <tt/parameter/ the string can be filled with zeroes (string always 5 characters
335 long) or not, to be left or right justified to given pixel. See <tt/ggraph.h/ for predefined
336 values for <tt/parameter/.
342 <tt/char GetCharWidth (char character)/
344 This function returns real width (in pixels) of given character with current font. It can be used
345 for counting the length of string on screen, allowing for indentation or justification.
349 <tt/void LoadCharSet (struct fontdesc *myFont)/
351 This function forces GEOS to use given font instead of own. <tt/myFont/ should be casted from
352 pointer to the start of area where was loaded record from font file (VLIR structure).
356 <tt/void UseSystemFont (void)/
358 This function forces GEOS to use built-in BSW font.
360 <sect2>Bitmap handling
362 I'm not quite sure how are these functions working (except <tt/BitmapUp/) so you should
363 probably look into library sources and compare it with your knowledge. Please let me know
364 if something is wrong or broken.
368 <tt/void BitmapUp (struct iconpic *myPic)/
370 This function unpacks the bitmap and places it on the screen - just as you set it in the
371 <tt/struct iconpic/ pointer to which you pass. See <tt/gstruct.h/ for description of this
372 structure. Note that you can only use packed GEOS bitmaps - simple Photo Scrap is in this format.
376 <tt/void BitmapClip (char skipLeft, char skipRight, unsigned skipTop, struct iconpic *myPic)/
378 This function acts similar to <tt/BitmapUp/ but you can also define which parts of the bitmap are
379 to be drawn - you give the number of columns (8-pixel) to skip on the right and left of the bitmap,
380 and the number of rows to skip from the top if it.
384 <tt/void BitOtherClip (void *proc1, void *proc2, char skipLeft, char skip Right, unsigned skipTop,
385 struct iconpic *myPic)/
387 Similar to the previous one with some extension. <tt/proc1/ is called before reading a byte (it
388 returns in .A next value), and <tt/proc2/ is called every time the parser reads a byte which is
389 not a piece of pattern (byte of code greater than 219). Both procedures should be written
390 separately in assembler and declared as <tt/__fastcall__/ returning char.
392 <sect1>Menus and Icons
394 Here you will find information about functions related with menus and icons.
398 Menus are essencial for GUI. GEOS can handle only one menu at a time, but each menu can call
399 another one, which results in submenu tree. There can be up to 8 menu levels, each one with up
402 Menus are initialized with <tt/DoMenu/ and then Kernal takes care for everything. Your code
403 (called from event handler) should be a function without parameters, returning void. You should
404 use <tt/DoPreviousMenu/ or <tt/GotoFirstMenu/ at least once in its code to have the screen clean.
408 <tt/void DoMenu (struct menu *myMenu)/
410 This function initializes GEOS menu processor and exits. See <tt/DoMenu structure/ for more
411 information about it. Know that many GEOS application just initializes the screen, menu and
412 exits to main Kernal loop, this proves the power of <tt/DoMenu/.
416 <tt/void ReDoMenu (void)/
418 This simply redraws the menu at lowest level. It works like calling <tt/DoMenu/ again with
423 <tt/void RecoverMenu (void)/
425 This function erases current menu from the screen. It doesn't change the menu level.
427 <sect3>RecoverAllMenus
429 <tt/void RecoverAllMenus (void)/
431 This calls <tt/RecoverMenu/ and erases all menus from the screen. Then the menu level is
434 <sect3>DoPreviousMenu
436 <tt/void DoPreviousMenu (void)/
438 This functions causes menu processor to go back one menu level. You should use it in menu
439 handler code to have the screen clean.
443 <tt/void GotoFirstMenu (void)/
445 This one jumps back to the topmost menu. If there is only menu and submenu it works the
446 same as <tt/DoPreviousMenu/.
448 <sect2>Icon Functions
450 Icons are working similar to menus except the fact that there is only one level. Icons are
451 defined as a screen area filled with a bitmap, but if you would setup icons and erase the
452 screen they are still active and clicking in the place where formerly an icon was will cause
453 an effect. Similary if you would setup icons and then turn them off with <tt/ClearMouseMode/
454 the bitmap will be still on the screen but clicking on it would not cause any action.
455 There is only one, but powerful icon function.
459 <tt/void DoIcons (struct icontab *myIconTab)/
461 This function initializes all icons that are present on the screen at once. For more information
462 look at <tt/Icons/ chapter in this manual.
466 This chapter covers the most powerful GEOS user interface function - <tt/DoDlgBox/.
472 <tt/char DoDlgBox (char *dialogString)/
474 DialogBox returns one byte. It can be the value of one of six standard icons (see <tt/gdlgbox.h/)
475 or whatever closing routine passes. Register <tt/r0L/ also contains this value.
477 Read structures chapter for the specs of the <tt/dialogString/.
479 <sect3>RstrFrmDialogue
481 <tt/char RstrFrmDialogue/
483 This function called from within DialogBox event immediately closes the DialogBox and returns
484 the owner ID (or whatever caller has in the .A register).
486 <sect2>GEOSLib extensions
488 To simplify usage of DoDlgBox from C I've wrote some help functions - wrappers for DoDlgBox,
489 with predefined data. In one word - these are standard DialogBoxes you can see in almost every
492 <sect3>DlgBoxYesNo, DlgBoxOkCancel, DlgBoxOk
494 <tt/char DlgBoxYesNo (char *line1, char *line2)/
496 <tt/char DlgBoxOkCancel (char *line1, char *line2)/
498 <tt/void DlgBoxOk (char *line1, char *line2)/
500 These function show two lines of text in standard-sized DialogBox. You can read the code of
501 pressed icon from return value. E.g. for <tt/DlgBoxYesNo/ it can only be <tt/YES/ or <tt/NO/.
502 You can pass an empty string or NULL to get a blank line.
504 <sect3>DlgBoxGetString
506 <tt/char DlgBoxGetString (char *string, char strlen, char *line1, char *line2)/
508 This function prompts user for entering a string of at most <tt/strlen/ characters. It is returned
509 in <tt/string/. The two given lines of text are shown above the input line. Please remember
510 that there is also <tt/CANCEL/ icon in the DialogBox and you should test if user confirmed his
511 input or gave up. The <tt/string/ is also shown so you can place default input there or remember
512 to place <tt/NULL/ at start.
514 <sect3>DlgBoxFileSelect
516 <tt/char DlgBoxFileSelect (char *class, char filetype, char *filename)/
518 This routine is the standard file selector. It can return <tt/OPEN/, <tt/CANCEL/ or disk error
519 on reading the directory or opening the disk.
520 There is also <tt/DISK/ icon shown, but it is handled internally. You pass as input parameters
521 <tt/filetype/ and pointer to string containing the first part of file's class. If this string is
522 empty (<tt/NULL/ at the start), then all files with given filetype will be shown.
524 At present this file selector handles only first 16 files of given type and supports only one
527 <sect1>Mouse, Sprites and Cursors
529 You will find here functions related to sprite and mouse drawing and handling.
531 <sect2>Mouse related functions
533 These cover mouse - as a general pointing device, but expect user to utilize as different devices
534 as digital or analog joystick, mouse, lightpen or koalapad (whatever it is).
536 <sect3>StartMouseMode
538 <tt/void StartMouseMode (void)/
540 This function initializes mouse vectors - <tt/mouseVector/ and <tt/mouseFaultVec/, and then
543 <sect3>ClearMouseMode
545 <tt/void ClearMouseMode (void)/
547 This function disables all mouse actitivies - icons and menus stop to respond to mouse events,
548 but they are not cleared from the screen.
550 <sect3>MouseUp and MouseOff
552 <tt/void MouseUp (void)/
554 <tt/void MouseOff (void)/
556 The first function turns the mouse pointer on. It will appear on next IRQ. The second one does
557 the opposite - it turns off the pointer, but its position is still updated by input driver.
561 <tt/char IsMseInRegion (struct window *myWindow)/
563 This function tests if mouse pointer is actually in given range of screen. See <tt/gsprite.h/ for
564 description of bits in return values - they describe the position in detail.
568 You are free to use any of the eight sprites, but keep in mind that sprite 0 is actually the mouse
569 pointer and sprite 1 can be overwritten when using text prompt. You don't have to worry about
570 40/80 column issues because GEOS128 has pretty good sprite emulator for VDC.
574 <tt/void DrawSprite (char sprite, char *mySprite)/
576 This function initializes the sprite data. <tt/mySprite/ is a 63-byte table with bitmap data, which
577 is copied to system sprite area (at <tt/sprpic/ - see <tt/gsym.h/). Hardware sprite registers are
578 not initialized and sprite is not yet visible.
582 <tt/void PosSprite (char sprite, struct pixel *myPixel)/
584 This function positions the sprite on the screen. Given coordinates are screen ones - they are
585 converted to sprite coordinates by GEOS. Due to this you cannot use this function to position your
586 sprite off the left or top to the screen.
588 <sect3>EnablSprite and DisablSprite
590 <tt/void EnablSprite (char sprite)/
592 <tt/void DisablSprite (char sprite)/
594 These two functions are responsible for making the sprite visible or not.
596 <sect2>Cursors and Console
598 <sect3>InitTextPrompt
600 <tt/void InitTextPrompt (char height)/
602 This function initializes sprite 1 for text prompt with given <tt/height/. This parameter can be in
605 <sect3>PromptOn and PromptOff
607 <tt/void PromptOn (struct pixel *myPixel)/
609 <tt/void PromptOff (void)/
611 The first function places text prompt in given place and enables blinking.
612 The second one is pretty self-explanatory.
616 <tt/char GetNextChar (void)/
618 This function gets next character from the keyboard queue. If the queue is empty it returns
619 <tt/NULL/, otherwise you receive true ASCII code of a character or value of special (function)
620 key. See <tt/gsprite.h/ for list of them.
624 This chapter covers slightly low-level disk routines. You should use them with care, because
625 you may easily corrupt data on disks. Also remember that contemporary GEOS supports many various
626 devices and sticking to 1541 track layout (e.g. expecting the directory on track 18) might be
629 For some purposes you might consider using <tt/dio.h/ interface to disk access. It is native.
631 All GEOS disk functions return error code in X register. In some cases this is returned by
632 GEOSLib function (if its type is <tt/char/), but in all cases last error is saved in <tt/__oserror/
633 location. If it is nonzero - an error occured. See <tt/gdisk.h/ for the list of possible errorcodes.
634 You need to include <tt/errno.h/ to get <tt/__oserror/, together with standard <tt/errno/. The
635 latter gives less verbose, but still usable information and can be used with <tt/strerror/.
636 Probably you will get more information using <tt/_stroserror/ in similar way.
638 For passing parameters use almost always pointer to your data e.g. <tt/ReadBuff (&myTrSe)/.
640 <sect2>Buffer functions
642 These functions are taking single data sector (256 bytes) to read or write on a disk.
644 <sect3>ReadBuff and Writebuff
646 <tt/char ReadBuff (struct tr_se *myTrSe)/
648 <tt/char WriteBuff (struct tr_se *myTrSe)/
650 These functions read and write sector placed at <tt/diskBlkBuf/.
652 <sect3>GetBlock and ReadBlock
654 <tt/char GetBlock (struct tr_se *myTrSe, char *buffer)/
656 <tt/char ReadBlock (struct tr_se *myTrSe, char *buffer)/
658 These two functions are reading a single block directly at 256 byte array placed at <tt/buffer/.
659 The difference between them is that <tt/GetBlock/ will initialize TurboDos in drive if it was not
660 enabled. <tt/ReadBlock/ assumes that it is already enabled thus being slightly faster.
662 <sect3>PutBlock, WriteBlock, VerWriteBlock
664 <tt/char PutBlock (struct tr_se *myTrSe, char *buffer)/
666 <tt/char WriteBlock (struct tr_se *myTrSe, char *buffer)/
668 <tt/char VerWriteBlock (struct tr_se *myTrSe, char *buffer)/
670 Similar to previous but needed for writting the disk. <tt/VerWriteBlock/ verifies the data after
671 writting. In case of error five tries are attempted before error code is returned.
673 <sect2>Directory header
675 Functions described here are operating on <tt/curDirHeader/ where current disk header is stored.
676 On larger capacity drives (than 1541) the second part of directory header in <tt/dir2Head/.
680 <tt/void GetPtrCurDkNm (char *diskName)/
682 This function fills given character string with the name of current disk. It is converted to C
683 standard - string is terminated with <tt/NULL/ character instead of code 160 as in Commodore DOS.
684 Note that passed pointer must point to an array of at least 17 bytes.
686 <sect3>GetDirHead and PutDirHead
688 <tt/char GetDirHead (void)/
690 <tt/char PutDirHead (void)/
692 These functions are reading and writting the directory header. You should use <tt/GetDirHead/ before
693 using any functions described below, and you should use <tt/PutDirHead/ to save the changes on the
694 disk. Otherwise they will be lost. Operating area is the <tt/curDirHead/.
698 <tt/unsigned CalcBlksFree (void)/
700 This function returns the number of free blocks on current disk. It is counted using data in
701 <tt/curDirHead/ so you must initialize the disk before calling it.
705 <tt/char ChkDskGEOS (void)/
707 This functions checks <tt/curDirHead/ for GEOS Format identifier. It returns either true or false,
708 and also sets <tt/isGEOS/ properly. You must initialize the disk before using this.
712 <tt/char SetGEOSDisk (void)/
714 This function initializes disk for use with GEOS. It sets indicator in directory header and
715 allocates a sector for the directory of border files. You don't need to initialize the disk before
720 <tt/char FindBAMBit (struct tr_se *myTrSe)/
722 This function returns the bit value from BAM (Block Allocation Map) for given sector. The bit is
723 set if the sector is free to use. Returned value is always zero if the sector is already allocated.
724 In fact, this function could be used in a following way:
726 #define BlockInUse FindBAMBit
728 if (!BlockInUse(&myTrSe)) {
729 ... block not allocated ...
733 Anyway, I feel that this function is too low-level.
735 <sect3>BlkAlloc and NxtBlkAlloc
737 <tt/char BlkAlloc (struct tr_se output[&rsqb, unsigned length)/
739 <tt/char NxtBlkAlloc (struct tr_se *myTrSe, struct tr_se output[&rsqb, unsigned length)/
741 Both functions are allocating enough disk sectors to fit the number of <tt/length/ in them. You
742 will find output in <tt/output/ which is table of <tt/struct tr_se/. The last entry will have the
743 number of track equal to 0 and sector equal to 255. The simpliest way of using them is to use
744 predefined space in GEOS data space and pass <tt/fileTrScTab/, which is a predefined table.
746 The difference between those two is that <tt/NextBlkAlloc/ will start allocating from given sector,
747 and <tt/BlkAlloc/ starts from the first nonused sector.
749 You need to use <tt/PutDirHead/ later to save any changes in BAM.
753 <tt/char FreeBlock (struct tr_se *myTrSe)/
755 Simply deallocates a block in BAM. You need to update BAM with <tt/PutDirHead/.
759 <tt/struct tr_se SetNextFree (struct tr_se *myTrSe)/
761 This function finds the first free sector starting from given track and sector and allocates it.
762 It might return the same argument if the given block is not allocated. I wanted it to be type
763 clean, but it made usage a bit tricky. To assign a value to own <tt/struct tr_se/ you have to
764 cast both variables to <tt/unsigned/. E.g.
768 (unsigned)myTrSe=(unsigned)SetNextFree(&otherTrSe);
771 In this example <tt/otherTrSe/ can be replaced by <tt/myTrSe/.
773 NOTE that you <em/must/ use casting to have correct values.
775 <sect2>Low-level disk IO
777 Functions described here are more usable in kernal or drivers code, less common in applications,
778 but who knows, maybe someone will need them.
780 <sect3>EnterTurbo, ExitTurbo, PurgeTurbo
782 <tt/void EnterTurbo (void)/
784 <tt/void ExitTurbo (void)/
786 <tt/void PurgeTurbo (void)/
788 These functions are interface to GEOS TurboDos feature which makes slow Commodore drives a bit
789 more usable. <tt/EnterTurbo/ enables TurboDos unless it is already enabled. If not, then you will
790 have to wait a bit to transfer TurboDos code into disk drive RAM. <tt/ExitTurbo/ disables TurboDos.
791 This is useful for sending some DOS commands for drive e.g. for formatting. Note that before any
792 interaction with Kernal in ROM you have to call <tt/InitForIO/. You don't have to worry about speed.
793 <tt/EnterTurbo/ will only enable TurboDos (no code transfer) if TurboDos was disabled with
794 <tt/ExitTurbo/. <tt/PurgeTurbo/ acts different from <tt/ExitTurbo/ - it not only disables TurboDos,
795 but also removes it from drive RAM (not quite true, but it works like that). After using
796 <tt/PurgeTurbo/ the next call to <tt/EnterTurbo/ will reload drive RAM.
798 <sect3>ChangeDiskDevice
800 <tt/char ChangeDiskDevice (char newDevice)/
802 This function changes logical number of current device (in fact drives only) with given one. It is
803 usable for swapping drives. There's no check if given <tt/newDevice/ already exist, so if you want
804 to change the logical number of drive 8 to 9 and you have drive number 9 then GEOS will probably
805 hang on disk access. Use safe, large numbers. Note that safe IEC range is 8-31.
807 <sect2>Disk Initialization
809 GEOS has two functions for initialization ('logging in' as they say on CP\M) the disk.
812 <tt/char OpenDisk (void)/
814 This function initializes everything for a new disk. It loads and enables TurboDos if needed.
815 Then the disk is initialized with <tt/NewDisk/. Next, <tt/GetDirHead/ initializes <tt/curDirHead/.
816 Disk names are compared and if they differ then disk cache on REU is cleared. Finally format is
817 checked with <tt/ChkDkGEOS/ and disk name is updated in internal tables.
821 <tt/char NewDisk (void)/
823 This function is similar to DOS command I. It clears REU cache and enables TurboDos if needed.
827 This section cover GEOS file interface.
829 <sect2>Directory handling
831 Functions described here are common for SEQ and VLIR structures.
833 <sect3>Get1stDirEntry and GetNxtDirEntry
835 <tt/struct filehandle *Get1stDirEntry (void)/
837 <tt/struct filehandle *GetNxtDirEntry (void)/
839 These two functions are best suited for scanning whole directory for particular files. Note that
840 returned filehandles describes all file slots in the directory - even those with deleted files.
841 The return value can be obtained by casting both sides to <tt/unsigned/ - as in <tt/SetNextFree/
842 function or read directly after call to those two functions from <tt/r5/. Current sector number
843 is in <tt/r1/ and sector data itself is in <tt/diskBlkBuf/.
847 <tt/char FindFile (char *fName)/
849 This function scans whole directory for the given filename. It returns either 0 (success) or 5
850 (FILE_NOT_FOUND, defined in <tt/gdisk.h/) or any other fatal disk read error. After successful
851 <tt/FindFile/ you will have <tt/struct filehandle/ at <tt/dirEntryBuf/ filled with file's data and
852 other registers set as described in <tt/GetNxtDirEntry/.
856 <tt/char FindFTypes (char *buffer, char fType, char fMaxNum, char *classTxt)/
858 This function scans directory and fills a table at <tt/buffer/ with <tt/char [17]/ entries.
859 <tt/fType/ is GEOS type of searched files and <tt/classTxt/ is a string for Class field in file
860 header. Class will match if given will be equal or shorter than that found in file's header block.
861 If you want just to find all files with given GEOS type you should pass empty string or <tt/NULL/ as
862 <tt/classTxt/. Be warned that for searching <tt/NON_GEOS/ files must pass <tt/NULL/ as <tt/classTxt/.
863 <tt/fMaxNum/ is the maximal number of found files, thus the <tt/buffer/ must
864 provide area of size equal to <tt/17 * fMaxNum/.
865 This function returns the number of found files, ranging from 0 to number passed as <tt/fMaxNum/.
866 Return value can be also restored from <tt/r7H/.
870 <tt/char DeleteFile (char *fName)/
872 This function deletes a file by its name. It works for SEQ and VLIR files.
876 <tt/char RenameFile (char *oldName, char *newName)/
878 I think it is obvious...
882 <tt/char GetFHdrInfo (struct filehandle *myFile)/
884 This function loads the file header into <tt/fileHeader/ buffer. Using after e.g. <tt/FindFile/
885 you can pass address of <tt/dirEntryBuf/.
887 <sect2>Common and SEQ structure
889 Functions described here are common for SEQ and VLIR structures because arguments passed are
890 starting track and sector which may point either to start of a chain for VLIR or data for SEQ.
894 <tt/char __fastcall__ GetFile(char flag, const char *fname, const char *loadaddr, const char *datadname, const char *datafname)/
896 This routine loads and runs a given file <tt/fname/. The file must be one of following types:
897 <tt/SYSTEM, DESK_ACC, APPLICATION, APPL_DATA, PRINTER,/ or <tt/INPUT_DEVICE/. The execution
898 address is taken from file header. If it is zero, then file is only loaded. Only the first chain
899 from VLIR files is loaded. If <tt/flag/ has bit 0 set then load address is taken from <tt/loadaddr/
900 and not from file header. In this case <tt/APPLICATION/ files will be only loaded, not executed.
901 This does not apply to <tt/DESK_ACC/. If either bit 6 or 7 of <tt/flag/ are set, then 16 bytes from
902 <tt/datadname/ is copied to <tt/dataDiskName/ and 16 bytes from <tt/datafname/ goes to <tt/dataFileName/
903 thus becoming parameters for the new application. Pass <tt/NULL/ as any unused parameter.
908 <tt/char ReadFile (struct tr_se *myTrSe, char *buffer, unsigned fLength)/
910 This function reads at most <tt/fLength/ bytes into <tt/buffer/ from chained sectors starting at
915 <tt/char ReadByte (void)/
917 This function returns next byte from a file. Before the first call to it you must load <tt/r5/
918 with <tt/NULL/, <tt/r4/ with sector buffer address and <tt/r1/ with track and sector of the
919 first block of a file.
920 Remember to not modify <tt/r1/, <tt/r4/ and <tt/r5/. These registers must be preserved between
921 calls to <tt/ReadByte/.
923 Returned value is valid only if there was no error. End of file is marked as <tt/BFR_OVERFLOW/
924 in <tt/__oserror/, this is set when trying to read one byte after the end of file, in this case
925 returned value is invalid.
929 <tt/char SaveFile (char skip, struct fileheader *myHeader)/
931 <tt/SaveFile/ will take care of everything needed to create a GEOS file, no matter VLIR of SEQ
932 structure. All you need to do is to place data in proper place and prepare a header which will
933 contain all information about a file. The <tt/skip/ parameter says how many directory pages you
934 want to skip before searching for a free slot for directory entry. In most cases you will put
937 You have to declare a <tt/struct fileheader/ and fill it with proper values. There is only one
938 difference - the first two bytes which are link to nonexistant next sector are replaced by a
939 pointer to the DOS filename of the file.
941 When saving sequential files two most important fields in <tt/struct fileheader/ are <tt/fileheader.load_address/
942 and <tt/fileheader.end_address/.
946 <tt/char FreeFile (struct tr_se myTable[])/
948 This function deallocates all sectors contained in passed table.
952 <tt/char FollowChain(struct tr_se *myTrSe, char *buffer)/
954 This function fills a <tt/struct tr_se/ table at <tt/buffer/ with sector numbers for chain of
955 sectors starting with <tt/myTrSe/. You can pass such data (<tt/buffer/) to e.g. <tt/FreeFile/.
957 <sect2>VLIR structure
959 Here are informations about VLIR files (called later as RecordFile) and functions.
961 VLIR is a file which consists of up to 127 SEQ-like files called records. Each record is like one
962 SEQ structure file. Records are grouped together, described by common name - VLIR file name and
963 own number. Each record pointed by its number is described by starting track and sector numbers.
964 VLIR structures allow records to be empty (<tt/tr_se/ of such record is equal to <tt/{NULL,$ff}/),
965 or even non-exist (<tt/{NULL,NULL}/). Any other numbers represent starting track and sector of
968 In GEOS there can be only one file opened at a time. Upon opening VLIR file some information
969 about it are copied into memory. You can retrieve records table at <tt/fileTrScTab/ (table of
970 128 <tt/struct tr_se/) and from <tt/VLIRInfo/ (<tt/struct VLIR_info/.
971 E.g. size of whole VLIR file can be retrieved by reading <tt/VLIRInfo.fileSize/.
973 <sect3>OpenRecordFile
975 <tt/char OpenRecordFile (char *fName)/
977 This function finds and opens given file. An error is returned if file is not found or if it is not
978 in VLIR format. Information in <tt/VLIRInfo/ is initialized. VLIR track and sector table is
979 loaded at <tt/fileTrScTab/ and will be valid until call to <tt/CloseRecordFile/ so don't modify it.
980 You should <tt/PointRecord/ before trying to do something with file.
982 <sect3>CloseRecordFile
984 <tt/char CloseRecordFile (void)/
986 This function calls <tt/UpdateRecordFile/ and clears internal GEOS variables.
988 <sect3>UpdateRecordFile
990 <tt/char UpdateRecordFile (void)/
992 This function will check <tt/VLIRInfo.fileWritten/ flag and if it is set, then <tt/curDirHead/ is
993 updated along with size and date stamps in directory entry.
997 <tt/char PointRecord (char recordNumber)/
999 This function will setup internal variables (and <tt/VLIRInfo.curRecord/) and return the track and
1000 sector of given record in <tt/r1/. Note that the data may not be valid (if record is non-existing
1001 you will get 0,0 and if it is empty - 255, 0).
1003 <sect3>NextRecord and PreviousRecord
1005 <tt/char NextRecord (void)/
1007 <tt/char PreviousRecord (void)/
1009 These two work like <tt/PointRecord/. Names are self-explanatory.
1013 <tt/char AppendRecord (void)/
1015 This function will append an empty record ( pair of 255,0 ) to current VLIR track and sector
1016 table. It will also set <tt/VLIRInfo.curRecord/ to its number.
1020 <tt/char DeleteRecord (void)/
1022 This function will remove current record from the table, and move all current+1 records one place
1023 back (in the table). Note that there's no BAM update and you must call <tt/UpdateRecordFile/ to
1028 <tt/char InsertRecord (void)/
1030 This function will insert an empty record in place of <tt/VLIRInfo.curRecord/ and move all following
1031 records in table one place forward (contents of <tt/VLIRInfo.curRecord/ after call to <tt/InsertRecord/
1032 can be found in <tt/VLIRInfo.curRecord + 1/).
1034 <sect3>ReadRecord and WriteRecord
1036 <tt/char ReadRecord (char *buffer, unsigned fLength)/
1038 <tt/char WriteRecord (char *buffer, unsigned fLength)/
1040 This function will load or save at most <tt/fLength/ bytes from currently pointed record into or from
1043 <sect1>Memory and Strings
1045 Functions covered in this section are common for whole C world - copying memory parts and
1046 strings is one of the main computer tasks. GEOS also has interface to do this. These functions
1047 are replacement for those like <tt/memset, memcpy, strcpy/ etc. from standard libraries.
1049 However some of them have slighty different calling convention (order of arguments to be specific),
1050 so please check their syntax here before direct replacing.
1052 Please note that the memory described as <em/strings/ are up to 255 characters (without
1053 counting the terminating <tt/NULL/), and <em/regions/ cover whole 64K of memory.
1057 <tt/void CopyString (char *dest, char *src)/
1059 This function copies string from <tt/src/ to <tt/dest/, until it reaches <tt/NULL/. <tt/NULL/
1064 <tt/char CmpString (char *s1, char *s2)/
1066 This function compares string <tt/s1/ to <tt/s2/ for equality - this is case sensitive, and both
1067 strings have to have the same length. It returns either <tt/true/ (non-zero) or <tt/false/ (zero).
1069 <sect2>CopyFString and CmpFString
1071 <tt/void CopyFString (char length, char *dest, char *src)/
1073 <tt/char CmpFString (char length, char *s1, char *s2)/
1075 These two are similar to <tt/CopyString/ and <tt/CmpString/ except the fact, that you provide
1076 the length of copied or compared strings. The strings can also contain several <tt/NULL/
1077 characters - they are not treated as delimiters.
1081 <tt/unsigned CRC (char *src, unsigned length)/
1083 This function calculates the CRC checksum for given memory range. I don't know if it is
1084 compatible with standard CRC routines.
1086 <sect2>FillRam and ClearRam
1088 <tt/void FillRam (char *dest, char value, unsigned length)/
1090 <tt/void ClearRam (char *dest, unsigned length)/
1092 Both functions are filling given memory range. <tt/ClearRam/ fills with <tt/NULLs/, while
1093 <tt/FillRam/ uses given <tt/value/. Be warned that these functions destroy <tt/r0, r1 and
1094 r2L/ registers. <tt/FillRam/ is an alias for <tt/memset/.
1098 <tt/void MoveData (char *dest, char *src, unsigned length)/
1100 This functions copies one memory region to another. There are checks for overlap and the
1101 non-destructive method is chosen. Be warned that this function destroys contents of
1102 <tt/r0, r1 and r2/ registers. This is also alias for <tt/memcpy/
1106 <tt/void InitRam (char *table)/
1108 This function allows to initialize multiple memory locations with single bytes or strings.
1109 This is done with <tt/table/ where everything is defined. See structures chapter for description of
1110 <tt/InitRam's/ command string.
1112 <sect2>Stash, Fetch, Swap, and VerifyRAM
1114 <tt/void StashRAM (char bank, unsigned length, char *reuAddress, char *cpuAddress)/
1116 <tt/void FetchRAM (char bank, unsigned length, char *reuAddress, char *cpuAddress)/
1118 <tt/void SwapRAM (char bank, unsigned length, char *reuAddress, char *cpuAddress)/
1120 <tt/ char VerifyRAM (char bank, unsigned length, char *reuAddress, char *cpuAddress)/
1122 These functions are interface to REU - Ram Expansion Unit. I think that they are self-explanatory.
1123 You can check for REU presence by taking value of <tt/ramExpSize/.
1125 <sect1>Processes and Multitasking
1127 Weird? Not at all. GEOS has limited multitasking ability. You can set up a chain of functions
1128 called in specified intervals and you can put the main program to sleep without disturbing other
1129 tasks and making user interface unresponsive.
1131 <sect2>InitProcesses
1133 <tt/void InitProcesses (char number, struct process *processTab)/
1135 This is the main initialization routine. After calling it processes are set up, but not
1136 enabled. The parameters for <tt/InitProcesses/ are:
1138 <item><tt/number/ - number of processes
1139 <item><tt/processTab/ - table of <tt/struct process/, with size equal to <tt/number/
1142 Single task is described by entry in <tt/processTab/, it contains two values - <tt/pointer/ to
1143 task function and number of <tt/jiffies/ which describe the delay between calls to task. On PAL
1144 systems there are 50 jiffies per second, while on NTSC there are 60.
1146 The maximum number of tasks is 20. Be warned that GEOS doesn't check if parameters are valid and
1147 if <tt/processTab/ would be too large it would overwrite existing data in GEOS space.
1149 There's one important thing - the last entry in <tt/processTab/ has to be <tt/NULL,NULL/, so the
1150 maximum size of <tt/processTab/ is equal to 21.
1152 See description of <tt/process/ structure for more detailed discussion on this.
1154 <sect2>RestartProcess and EnableProcess
1156 <tt/void RestartProcess (char processNumber)/
1158 <tt/void EnableProcess (char processNumber)/
1160 These two functions start the task counter. <tt/RestartProcess/ for each process should be called
1161 after <tt/InitProcesses/, because it resets all flags and counters and it starts the counters.
1163 <tt/RestartProcess/ enables counters and sets their initial value to that given in <tt/processTab/.
1165 <tt/EnableProcess/ forces given process to execute by simulating the timer running out of time.
1167 <sect2>BlockProcess and UnBlockProcess
1169 <tt/void BlockProcess (char processNumber)/
1171 <tt/void UnBlockProcess (char processNumber)/
1173 <tt/BlockProcess/ disables the execution of given process, but this does not disable the timers.
1175 <tt/UnBlockProcess/ does the opposite.
1177 <sect2>FreezeProcess and UnFreezeProcess
1179 <tt/void FreezeProcess (char processNumber)/
1181 <tt/void UnFreezeProcess (char processNumber)/
1183 <tt/FreezeProcess/ disables timer for given process. <tt/UnFreezeProcess/ does the opposite.
1184 This is not equal to <tt/RestartProcess/ as timers are not filled with initial value.
1188 <tt/void Sleep (unsigned jiffies)/
1190 This function is multitasking sleep - the program is halted, but it doesn't block other functions.
1191 The only argument here is the number of jiffies to wait until app will wake up.
1193 You can force to sleep not only the main application routine, but also processes-tasks. Be warned
1194 that the maximum number of sleeping functions is 20. If it would be larger it will overwrite
1195 parameters of already sleeping functions in GEOS kernal data space, leading to crash.
1197 <sect1>System Functions
1201 <tt/void FirstInit (void)/
1203 This function initializes some GEOS variables and mouse parameters. This is called on GEOS boot
1204 up. You shouldn't use this unless you know what you are doing.
1206 <sect2>InitForIO and DoneWithIO
1208 <tt/void InitForIO (void)/
1210 <tt/void DoneWithIO (void)/
1212 These functions are called by some disk routines. You should call them only if you want to
1213 do something with IO registers or call one of Kernal's routines.
1217 <tt/void MainLoop (void)/
1219 Returns control to the system. Any code between call to <tt/MainLoop/ and the end of current
1220 function will never be executed. When in <tt/MainLoop/ systems waits for your action - using
1221 icons, keyboard or menus to force some specific action from program. You have to define
1222 proper handlers before that.
1226 <tt/void EnterDeskTop (void)/
1228 Calling this function will instantly terminate your program and bring you back to DeskTop.
1229 WARNING! It is not an equivalent of <tt/exit()/, library destructors code and functions
1230 registered with <tt/atexit()/ will not be called. In fact, you should always use
1231 <tt/exit()/ instead.
1235 <tt/void ToBASIC (void)/
1237 This one is another way of finishing application - forcing GEOS to shutdown and exit to BASIC.
1238 I was considering whether to include it or not, but maybe someone will need it. Which is I doubt.
1239 It has the same dangerous features as <tt/EnterDeskTop/.
1243 <tt/void Panic (void)/
1245 This calls system's <tt/Panic/ handler - it shows dialog box with message
1247 System error at:xxxx
1249 where <tt/xxxx/ is last known execution address (caller). By default this is bound to <tt/BRK/
1250 instruction, but it might be usable in debugging as kind of <tt/assert/. (Note that <tt/assert/
1251 is available as a separate function and will give you more information than that).
1253 System is halted after call to <tt/Panic/ which means that library destructors will not be
1254 called and some data may be lost (no wonder you're panicking).
1258 <tt/void CallRoutine (void *myFunct)/
1260 This is system caller routine. You need to provide pointer to a function and it will be immediately
1261 called, unless the pointer is equal to <tt/NULL/. This is the main functionality of this function -
1262 you don't need to check if the pointer is valid.
1264 <sect2>GetSerialNumber
1266 <tt/unsigned GetSerialNumber (void)/
1268 This function returns the serial number of system. It might be used for copy-protection.
1269 However, please remember that the Free Software is a true power and you are using it
1274 <tt/char GetRandom (void)/
1276 This function returns a random number. It can be also read from <tt/random/ e.g.
1280 but by calling this function you are sure that the results will be always different.
1281 <tt/random/ is updated once a frame (50Hz PAL) and on every call to <tt/GetRandom/.
1283 Note that it is not the same as <tt/rand/ function from the standard library. <tt/GetRandom/
1284 will give you unpredictable results (if IRQs would occur between calls to it) while
1285 <tt/rand/ conforms to the standard and for given seed (<tt/srand/) it always returns with the
1286 same sequence of values.
1290 <tt/void SetDevice (char device)/
1292 This function sets current device to given. It might be used together with <tt/InitForIO/,
1293 <tt/DoneWithIO/ and some Kernal routines. Unless new device is a disk drive this only sets
1294 new value in <tt/curDevice/, in other case new disk driver is loaded from REU or internal RAM.
1298 <tt/char get_ostype (void)/
1300 This function returns GEOS Kernal version combined (by logical OR) with machine type. Read
1301 <tt/gsys.h/ for definitions of returned values.
1305 <tt/char get_tv (void)/
1307 This function returns PAL/NTSC flag combined (by logical OR) with 40/80 columns flag. This is
1308 not the best way to check if screen has 40 or 80 columns since PAL/NTSC check is always
1309 performed and it can take as long as full raster frame. If you just want to know if
1310 screen has 40 or 80 columns use expression <tt/graphMode & 0x80/ which returns <tt/0/ for
1311 40 columns and <tt/0x80/ for 80 columns. Remember that this parameter can be changed during
1312 runtime. It is unclear if this will work for GEOS 64 so you probably do not want to test
1313 anything if not running under GEOS128. Use <tt/get_ostype/ to check it. Read <tt/gsys.h/ for
1314 definitions of returned values.
1316 <sect>Library Structures
1318 To simplify usage and optimize passing parameters to functions I have declared several structures
1319 which describe most common objects. Some of these structures are bound to static addresses in
1320 GEOS data space ($8000-$8fff), so you can use their fields directly in optimized way.
1321 Please see <tt/gsym.h/ and find them. All structures are defined in <tt/gstruct.h/ and you may
1322 find also some comments there.
1324 <sect1>Graphics Structures
1328 One simple structure describing a point on the screen.
1332 This structure describes a font in one pointsize. There is current font - <tt/struct fontdesc/
1333 bound to <tt/curFontDesc/. You can also force GEOS to use your own fonts by calling
1334 <tt/LoadCharSet/. You just need to open a VLIR font file and load one record - one pointsize
1335 somewhere. At the start of this area you already have all data for <tt/fontdesc/ so you can
1336 pass a pointer to the load adress of that pointsize to <tt/LoadCharSet/. (Note that although
1337 it has 'Load' in the name, that function loads only GEOS internal data structures, not data
1342 This widely used structure holds description of a region of the screen. It describes top-left and
1343 bottom-right corners of a window.
1347 Maybe the name isn't the best - it has nothing with <tt/DoIcons/ but with bitmap functions -
1348 <tt/BitmapUp/ for example. This structure holds parameters needed to properly decode and show
1349 a bitmap on the screen. Bitmap has to be encoded - if you have some non-GEOS bitmaps simply
1350 convert them to Photo Scraps - this is the format used by all GEOS bitmap functions - <tt/DoIcons/
1355 These structures describe click boxes (icons) that can be placed on screen or in a dialog box.
1359 This is the definition of a single click box. Please see <tt/gstruct.h/ for description of its fields.
1363 This is toplevel description of icons to be placed and enabled on the screen. This structure
1364 has following fields:
1366 <item><tt/char number/ - total number of icons declared here
1367 <item><tt/struct pixel mousepos/ - after finishing <tt/DoIcons/ mouse pointer will be placed in
1368 this point allowing you to have hint for user what is default action
1369 <item><tt/struct icondef tab[&rsqb/ - this table of size equal to <tt/icontab.number/ contains
1370 descriptions for all icons
1373 <sect1>File and Disk
1377 This simple structure holds track and sector number of something. Do not expect the track to be
1378 in range 1-35, as GEOS can support many various and weird devices. For example my C128 256K
1379 expansion is utilized as RAMDisk with layout of 4 tracks 128 sectors each. However assuming that
1380 track number equal to 0 is illegal might be wise.
1384 This is placeholder for file datestamp. This structure is also present in <tt/struct filehandle/.
1385 GEOS is not Y2K compliant, so if current file has in <tt/filehandle.date.year/ value less than 86
1386 you can safely assume that it is e.g. 2004 and not 1904.
1390 This is main file descriptor. It is either entry in the directory (returned from file functions)
1391 or its copy in <tt/dirEntryBuf/. This is optimized so you can safely get to the file's year e.g.
1392 by testing <tt/dirEntryBuf.date.year/ - it will be compiled to simple <tt/LDA, STA/.
1396 This structure holds fileheader description. You can load file's header into <tt/fileHeader/
1397 fixed area using <tt/GetFHdrInfo/. (note that <tt/fileHeader/ is a place in memory while
1398 <tt/fileheader/ is a structure).
1399 You will also need own fileheader for <tt/SaveFile/.
1401 <sect1>System Structures
1405 This structure is defined only for <tt/system_date/. It is slightly different from <tt/f_date/
1406 so I prepared this one. You can e.g. get or set current time using <tt/system_date.s_hour/ and
1407 <tt/system_date.s_minute/. Accesses to these will be optimized to simple <tt/LDA/ and <tt/STA/
1412 You should declare a table of that type to prepare data for <tt/InitProcesses/. The maximum number
1413 of processes is 20, and the last entry has to be equal to <tt/{NULL,NULL}/, so this table may hold
1414 only 21 entries. The first member of this structure (<tt/pointer/) holds the pointer to called
1415 function (void returning void), you will probably have to cast that pointer into <tt/unsigned int/.
1416 The second field <tt/jiffies/ holds the amount of time between calls to that function.
1417 On PAL systems there are 50 jiffies per second, while NTSC have 60 of them.
1419 <sect1>Few thing in detail...
1421 GEOSLib uses cc65 non-ANSI extensions to easily initialize data in memory. This is done with a
1422 kind of array of unspecified length and unspecified type. Here is how it goes:
1424 void example = {
1425 (char)3, (unsigned)3, (char)0 };
1427 Which will be compiled to following string of bytes:
1434 As you see this way it is possible to define data of any type in any order. You must remember to
1435 cast each member to proper type.
1437 <sect2>DoMenu structure
1439 <tt/DoMenu/ is responsible for everything concerned with menu processing. Many, many GEOS programs
1440 are just initializing screen and menu and exit to <tt/MainLoop/. In GEOSLib it is the same as
1441 returning from <tt/main/ function without using <tt/exit(0)/.
1443 Menu is described by two types of data - menu descriptors and menu items. Descriptor contains
1444 information about following menu items, and items are containing names of entries and either
1445 pointers to functions to execute or, in case of nested menus, pointers to submenu descriptors.
1446 Note that submenu descriptor can be top-level descriptor, there's no difference in structure,
1447 just in the content.
1449 Here is how single descriptor looks like:
1451 void myMenu = {
1452 (char)top, (char)bottom, // this is the size of the menubox
1453 (unsigned)left, (unsigned)right, // counting all items in current descriptor
1454 (char)number_of_items | type_of_menu, // number of following items ORed with
1455 // type of this menu, it can be either
1456 // HORIZONTAL or VERTICAL if you will have also bit 6 set then menu won't be closed
1457 // after moving mouse pointer outside the menubox. You can have at most 31 items.
1459 This is followed by <tt/number_of_items/ of following item description.
1462 "menuitemname", (char)item_type, (unsigned)pointer,
1463 "nextitemname", (char)item_type, (unsigned)pointer,
1465 "lastitemname", (char)item_type, (unsigned)pointer };
1466 // Note that there isn't ending <tt/NULL/ or something like that.
1468 <tt/pointer/ is a pointer to something, what it points for depends from <tt/item_type/. This one
1469 can have following values:
1471 <tt/MENU_ACTION/ - a function pointed by <tt/pointer/ will be called after clicking on menu item
1473 <tt/SUB_MENU/ - <tt/pointer/ points to next menu descriptor - a submenu
1475 Both of them can be ORed with <tt/DYN_SUB_MENU/ and then the <tt/pointer/ points to a function
1476 which will return in <tt/r0/ needed pointer (to function to execute or a submenu).
1478 For creating nested menus (you can have at most 8 levels of submenus) you need to declare such
1479 structure for each submenu and top level menu.
1481 <sect2>DoDlgBox command string
1483 <tt/DoDlgBox/ is together with <tt/DoMenu/ one of the most powerful routines in GEOS. It is
1484 responsible for creating dialog boxes, that is windows which task is to interact with user.
1485 Format of the command string is following:
1487 (window size and position)
1488 (commands and parameters)
1491 There is custom type defined for the command string: <tt/dlgBoxStr/.
1493 <sect3>Size and position
1495 The first element can be specified in two ways - by using default size and position or specifying
1496 own. The first case results in
1498 const dlgBoxStr example = {
1499 DB_DEFPOS (pattern_of_shadow),
1503 And the own size and position would be:
1505 const dlgBoxStr example = {
1506 DB_SETPOS (pattern, top, bottom, left, right)
1513 The next element of <tt/DoDlgBox/ command string are commands themselves. First six commands are
1514 default icons and the number of selected icon will be returned from window processor. The icons are
1515 <tt/OK, CANCEL, YES, NO, OPEN/, and <tt/DISK/. You can use predefined macros for use them, e.g.:
1518 DB_ICON(OK, DBI_X_0, DBI_Y_0),
1521 Note that the position is counted from top left corner of window, not entire screen and that the 'x'
1522 position is counted in cards (8-pixel) and not in pixels. This is true also for all following commands.
1523 <tt/DBI_X_0/ and <tt/DBI_Y_0/ are predefined (see <tt/gdlgbox.h/ for more), default positions
1524 which will make icons to appear on default window exactly where you would expect them.
1526 <tt/DB_TXTSTR (x, y, text)/ will cause to show given text in the window.
1528 <tt/DB_VARSTR (x, y, ptr)/ works as above, but here you are passing a pointer to a zero page location
1529 where the address of text is stored. This is useful for information windows where only text content
1530 is variable. Consider following:
1534 r15=(unsigned)text; // in code just before call to DoDlgBox
1536 DB_VARSTR (TXT_LN_X, TXT_LN_1_Y, &r15),
1539 will cause to appear the word ``foo'' in the window, but you may store the pointer to any text in
1540 <tt/r15/ (in this case) before call to DoDlgBox.
1542 <tt/DB_GETSTR(x, y, ptr, length)/ - will add input from keyboard feature. <tt/ptr/ works as in
1543 previous example and points to place where text is to be stored. Note that the contents of this
1544 place will be shown upon creating window. <tt/length/ is the maximum number of characters to input.
1546 <tt/DB_SYSOPV(ptr)/ - this sets <tt/otherPressVec/ to given pointer. It is called on every keypress.
1548 <tt/DB_GRPHSTR(ptr)/ - data for this command is the pointer for <tt/GraphicsString/ commands.
1550 <tt/DB_GETFILES(x, y)/ - for standard window you should pass 4 for both x and y. This function
1551 draws file selection box and searches current drive for files. Before call to <tt/DoDlgBox/ you
1552 must load <tt/r7L/ with GEOS filetype of searched files and <tt/r10/ with class text. In <tt/r5/
1553 you have to load pointer to a <tt/char[17]/ where selected filename will be copied. It works
1554 like <tt/FindFTypes/ but is limited to first 16 files.
1556 <tt/DB_OPVEC(ptr)/ - this sets the new pointer for button press function, if you pass
1557 <tt/RstrFrmDialogue/ here you will cause the window to close after pressing mouse button.
1559 <tt/DB_USRICON(x, y, ptr)/ - places single user icon (click box) on window, <tt/ptr/ points at a
1560 <tt/struct icondef/ but fields <tt/x/ and <tt/y/ are not used here. You can have at most 8 click
1561 boxes in a window, this is internal limit of GEOS Kernal.
1563 <tt/DB_USRROUT(ptr)/ - this command causes to immediately call user routine pointed by <tt/ptr/.
1565 <sect2>GraphicsString command string
1567 <tt/GraphicsString/ is a very powerful routine to initialize whole screen at once. There are
1568 predefined macros for all commands, names are self-explanatory, see them in <tt/ggraph.h/. Last
1569 command have to be <tt/GSTR_END/. There is custom type defined for the command string: <tt/graphicStr/.
1571 Here is an example for clearing the screen:
1573 const graphicStr example = {
1576 RECTANGLETO(319,199)
1580 <sect2>InitRam table
1582 This type of data is used to initialize one or more bytes in many places at once. The format is
1585 void example = {
1586 (unsigned)address_to_store_values_at,
1587 (char)number_of_bytes_that_follow,
1588 (char)data,(char)data (...)
1589 // more such definitions
1590 (unsigned)NULL // address of 0 ends the table
1594 <sect2>Intercepting system vectors
1596 It is possible to intercept and hook in the GEOS Kernal using vectors. Here is a little example:
1598 void (*oldVector)(void);
1600 void NewVectorHandler(void) {
1601 // do something and at the end call the old vector routine
1605 void hook_into_system(void) {
1606 oldVector = mouseVector;
1607 mouseVector = NewVectorHandler;
1610 void remove_hook(void) {
1611 mouseVector = oldVector;
1615 In your <tt/main/ function you should call <tt/hook_into_system()/ but <em/after/ all calls to GEOS
1616 kernal (like <tt/DoMenu/, <tt/DoIcons/, etc.) - right before passing control to the <tt/MainLoop()/.
1617 It is critical to restore old vector values before exiting the program. If you have more than one
1618 place where you call <tt/exit()/ then it might be worth to register <tt/remove_hook/ function to
1619 be called upon exiting with <tt/atexit(&remove_hook);/ call. This way you will ensure that
1620 such destructor will be always called.
1622 That little example above intercepts <tt/mouseVector/. The <tt/NewVectorHandler/ function will be
1623 called every time the mouse button changes status. Other important vectors you should know about
1626 <item><tt/appMain/ - this is called from within <tt/MainLoop/ system loop
1627 <item><tt/keyVector/ - called whenever a keypress occurs
1628 <item><tt/intTopVector/ - called at the start of IRQ routine
1629 <item><tt/intBotVector/ - called at the end of IRQ routine