1 <!doctype linuxdoc system>
5 <!-- Title information -->
8 <author>Maciej Witkowiak, <htmlurl url="mailto:ytm@elysium.pl" name="ytm@elysium.pl">
9 <date>v1.3, 26.12.1999, 16.03.2000, 19-22.03.2000, 11,29.07.2000, 3-4,15.07.2001, 27.10.2001
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 It is safe to use these standard includes and its contents:
49 <tt/assert.h, conio.h, dio.h, errno.h, geos.h, joystick.h, mouse.h, stdlib.h, string.h, time.h/
51 It was not tested enough, but functions from these includes might work under GEOS:
54 I am an assembler programmer and GEOSLib was designed in such way that cc65 could emit the best
55 available code (well, the best as for machine :). Many of the <tt/void foo (void)/ functions are
56 just raw calls to Kernal (assembled just as <tt/jsr _foo/), look in <tt/gsym.h/, where you
57 will find many definitions of standard GEOS locations. Access to these addresses is optimized by
58 cc65 to simple <tt/lda/ and <tt/sta/. Don't be afraid to use the power of C.
62 You will not need c64 or c128 for development. The only hardware requirement is a PC capable of
63 runing cc65. You will however need c64 or c128 emulator and GEOS image disks (.d64) to test your
68 <item><em/cc65/ Excellent package containing C crosscompiler, crossassembler and linker, you
69 can get it from: <htmlurl url="http://www.von-bassewitz.de/uz/cc65/"
70 name="http://www.von-bassewitz.de/uz/cc65/">
71 <item><em/VICE/ This is portable C64, C128 and few other Commodore computers emulator, you
72 can obtain it from: <htmlurl url="http://www.cs.cmu.edu/~dsladic/vice/vice.html"
73 name="http://www.cs.cmu.edu/~dsladic/vice/vice.html">. VICE package contains
74 c1541 program that is able to convert/unconvert GEOS files to disk images.
75 <item><em/Star Commander/ This tool is only for DOS. You will need it for transferring
76 object files from PC to 1541. There's also one important ability of this
77 tool - it automatically un-converts .cvt files into GEOS native format on
79 <item><em/cbm4linux/ A Linux kernel module that allows for communication with 1541 and
80 other Commodore IEC bus drives. It can be replacement for Star Commander if
81 you want only to transfer files to a disk and uncovert using GEOS program for
82 this purpose. Check out: <htmlurl url="http://www.lb.shuttle.de/puffin/cbm4linux/"
83 name="http://www.lb.shuttle.de/puffin/cbm4linux">
86 VICE and cc65 are portable - they run on variety of platforms - DOS, Win32 and UNIX. GEOSLib only
89 <em/Update:/ starting from v2.5.0 GEOSLib is a part of cc65 package as its GEOS support.
93 I want to thank Uz for his cc65 package, Alexander Boyce for his excellent GEOS Programmer's
94 Reference Guide and BSW for GEOS.
96 GEOSLib is covered by the same license as cc65. You can find the whole text among documentation.
97 I would really appreciate if you would like to send me your comments, suggestions, questions,
98 changes, bug reports etc. I will also appreciate if you will just give me a sign that you are
99 using GEOSLib - not especially something big and important, mail me even if you are just playing
102 You can send postcards with hellos to:
104 Maciej Witkowiak, ul. Slowackiego 6/57, 77-400 ZLOTOW
108 e-mail: <tt/ytm@elysium.pl/
110 <sect>What have you got and what to do with it?
112 This chapter describes some rules you ought to obey, and how to use GEOSLib.
116 Apart from this file, which merely describes only standard GEOS library functions, you should read
117 <tt/grc/ (GEOS resource compiler) documentation. There are informations about necessary resource
118 files (each GEOS application neeeds at least one) and the building process - what should be done
119 and in what order. Please also read cc65's documentation on how to compile C, assembler and link
122 All in all, you just need to place
124 #include <geos.h>
126 on top of your source.
128 As a general rule read the sources of example programs and read the headers. These are the most
129 reliable sources of knowledge ;). You will also find there many C macros representing various
130 arguments passed to functions. Please use them. You will find your sources easier to understand,
131 and it will be easier to find bugs.
133 All types used in GEOSLib are <tt/unsigned/.
135 Screen coordinates are given in pixels unless stated differently.
137 <sect1>Notes on style
139 Contrary to typical GEOS assembly program which has a main function called after loading that
140 setups the screen, menus, icons etc. exiting from <tt/main/ function in C is equivalent to
141 calling <tt/exit()/. These two are the only safe methods of terminating applications. DO NOT
142 USE <tt/EnterDeskTop/! Your data may be lost as library destructors and functions registered
143 with <tt/atexit/ will not be called.
145 For GEOS GUI applications the recommended program structure is to have everything initialized
146 in <tt/main/ function and at the end of it a call to <tt/MainLoop()/ function. WARNING! This
147 function never returns, any code between <tt/MainLoop();/ and the end of <tt/main/ will not
148 be executed. You have to call <tt/exit()/ explicitly somewhere in your code (e.g. in a menu
149 handler or via DialogBox action).
151 Whenever possible use definitions from <tt/gsym.h/. The resulting code is translated by cc65 into
152 series of <tt/lda/ and <tt/sta/, so you can't do it better :-).
154 Don't hesitate to use library functions. Everything was written with size and speed in mind. In
155 fact many calls are just redirections to GEOS kernal which results in simple <tt/jsr/.
157 You might wonder why I have chosen sometimes weird order of arguments in functions. It is because
158 I wanted to avoid unnecessary pushing and popping arguments from stack. cc65 can pass single <tt/int/
159 through CPU registers.
161 Do not try to compile in strict ANSI mode. Library uses cc65 extensions which are not available in
164 <sect>Library Functions
166 Functions here are sorted more or less in the way they appear in header files. This way I am able
167 to keep functions covering similar task near each other. All function names are identical to those
168 from <tt/geosSym/ file provided with GeoProgrammer package. Only my extensions to <tt/geosSym/
169 are covered by new names, but I tried to keep them in the naming convention.
173 This section covers drawing package of GEOS along with text output routines.
177 <tt/void SetPattern (char pattern)/
179 This function sets current pattern to given. There are 32 different patterns in GEOS. You can
180 see them together in the filling box in GeoPaint.
182 <sect2>GraphicsString
184 <tt/void GraphicsString (char *myGString)/
186 One of the more powerfull routines of GEOS. This function calls other graphic functions depending
187 on given command string. See structures chapter for more detailed description of the structure of it.
189 <sect2>Rectangle functions
191 Parameters to those functions are grouped in <tt/struct window drawWindow/. To speed up things and
192 reduce overhead this structure is glued to zero page locations, where all rectangle functions
193 expect their parameters. You can modify data directly (e.g. <tt/drawWindow.top=10/) or via
194 <tt/InitDrawWindow/ function. Contents of <tt/drawWindow/ are guaranteed not to change only when
195 using graphics functions. In other case you should keep your data in separate <tt/struct window/
196 and use <tt/InitDrawWindow/ before first call to rectangle functions.
198 <sect3>InitDrawWindow
200 <tt/void InitDrawWindow (struct window *myWindow)/
202 This function only copies contents of <tt/myWindow/ into system area of <tt/drawWindow/. Use it
203 if for some reason you have to keep window data out of zero page space.
207 <tt/void Rectangle (void)/
209 This draws on screen rectangle filled with current pattern.
211 <sect3>FrameRectangle
213 <tt/void FrameRectangle (char pattern)/
215 This one draws frame with given bit pattern (not a pattern from GEOS palette).
217 <sect3>InvertRectangle
219 <tt/void InvertRectangle (void)/
221 Just as the name says...
223 <sect3>ImprintRectangle and RecoverRectangle
225 <tt/void ImprintRectangle (void)/
227 <tt/void RecoverRectangle (void)/
229 These two functions are for copying parts of the screen to (<tt/Imprint/) and from (<tt/Recover/)
230 backbuffer of the screen. For example when drawing new menu box GEOS first uses
231 <tt/ImprintRectangle/ to save the area under the box, and restores it by <tt/RecoverRectangle/ upon
234 <sect2>Line Functions
236 GEOS drawing package is optimized so there are different functions for drawing vertical and
239 <sect3>HorizontalLine
241 <tt/void HorizontalLine (char pattern, char y, int xStart, int xEnd)/
243 This function draws horizontal line using given pattern - here it is a true bit pattern, not
244 pattern set by <tt/SetPattern/.
248 <tt/void InvertLine (char y, int xStart, int xEnd)/
250 There is only horizontal version.
254 <tt/void RecoverLine (char y, int xStart, int xEnd)/
256 This function recovers only one line. It is utilized by <tt/RecoverRectangle/. See its description
261 <tt/void VerticalLine (char pattern, char yStart, char yEnd, int x)/
263 This function draws vertical line using given pattern. Note that <tt/pattern/ is not a pattern
264 number as set in <tt/SetPattern/ but a true bit pattern.
268 <tt/void DrawLine (struct window *myWindow)/
270 <tt/top/ parameters of <tt/struct window/ describe the starting point of the line, while
271 <tt/bottom/ are for the ending point. Current pattern from <tt/SetPattern/ is used for drawing.
273 <sect2>Point Functions
275 Parameters to these two functions are passed by a pointer to own <tt/struct pixel/ filled with
280 <tt/void DrawPoint (struct pixel *myPixel)/
282 Draws single point on the screen, no matter what the current pattern is.
286 <tt/char TestPoint (struct pixel *myPixel)/
288 This function tests if given pixel is set and returns <tt/true/ (non-zero) or <tt/false/ (zero).
290 <sect2>Character and string output
294 <tt/cpputsxy (char x, char y, char *myString)/
296 <tt/cpputs (char *myString)/
298 Actually this is a part of <tt/conio/, but this function is non-standard. It is
299 a variety of <tt/cputs/ that will output string with proportional spacing, not
300 fixed like <tt/cputs/.
304 <tt/void PutChar (char character, char y, char x)/
306 This function outputs single character using current style and font to screen.
310 <tt/void PutString (char *myString, char y, int x)/
312 Same as <tt/PutChar/ except the fact that you can output whole <tt/NULL/-terminated string.
313 See <tt/ggraph.h/ for list of tokens that you can also place in the string - like <tt/CBOLDON/ or
318 <tt/void PutDecimal (char parameter, int value, char y, int x)/
320 This function converts <tt/value/ to its decimal representation and outputs it to the screen.
321 Depending on given <tt/parameter/ the string can be filled with zeroes (string always 5 characters
322 long) or not, to be left or right justified to given pixel. See <tt/ggraph.h/ for predefined
323 values for <tt/parameter/.
329 <tt/char GetCharWidth (char character)/
331 This function returns real width (in pixels) of given character with current font. It can be used
332 for counting the length of string on screen, allowing for indentation or justification.
336 <tt/void LoadCharSet (struct fontdesc *myFont)/
338 This function forces GEOS to use given font instead of own. <tt/myFont/ should be casted from
339 pointer to the start of area where was loaded record from font file (VLIR structure).
343 <tt/void UseSystemFont (void)/
345 This function forces GEOS to use built-in BSW font.
347 <sect2>Bitmap handling
349 I'm not quite sure how are these functions working (except <tt/BitmapUp/) so you should
350 probably look into library sources and compare it with your knowledge. Please let me know
351 if something is wrong or broken.
355 <tt/void BitmapUp (struct iconpic *myPic)/
357 This function unpacks the bitmap and places it on the screen - just as you set it in the
358 <tt/struct iconpic/ pointer to which you pass. See <tt/gstruct.h/ for description of this
359 structure. Note that you can only use packed GEOS bitmaps - simple Photo Scrap is in this format.
363 <tt/void BitmapClip (char skipLeft, char skipRight, int skipTop, struct iconpic *myPic)/
365 This function acts similar to <tt/BitmapUp/ but you can also define which parts of the bitmap are
366 to be drawn - you give the number of columns (8-pixel) to skip on the right and left of the bitmap,
367 and the number of rows to skip from the top if it.
371 <tt/void BitOtherClip (void *proc1, void *proc2, char skipLeft, char skip Right, int skipTop,
372 struct iconpic *myPic)/
374 Similar to the previous one with some extension. <tt/proc1/ is called before reading a byte (it
375 returns in .A next value), and <tt/proc2/ is called every time the parser reads a byte which is
376 not a piece of pattern (byte of code greater than 219). Both procedures should be written
377 separately in assembler and declared as <tt/__fastcall__/ returning char.
379 <sect1>Menus and Icons
381 Here you will find information about functions related with menus and icons.
385 Menus are essencial for GUI. GEOS can handle only one menu at a time, but each menu can call
386 another one, which results in submenu tree. There can be up to 8 menu levels, each one with up
389 Menus are initialized with <tt/DoMenu/ and then Kernal takes care for everything. Your code
390 (called from event handler) should be a function without parameters, returning void. You should
391 use <tt/DoPreviousMenu/ or <tt/GotoFirstMenu/ at least once in its code to have the screen clean.
395 <tt/void DoMenu (struct menu *myMenu)/
397 This function initializes GEOS menu processor and exits. See <tt/DoMenu structure/ for more
398 information about it. Know that many GEOS application just initializes the screen, menu and
399 exits to main Kernal loop, this proves the power of <tt/DoMenu/.
403 <tt/void ReDoMenu (void)/
405 This simply redraws the menu at lowest level. It works like calling <tt/DoMenu/ again with
410 <tt/void RecoverMenu (void)/
412 This function erases current menu from the screen. It doesn't change the menu level.
414 <sect3>RecoverAllMenus
416 <tt/void RecoverAllMenus (void)/
418 This calls <tt/RecoverMenu/ and erases all menus from the screen. Then the menu level is
421 <sect3>DoPreviousMenu
423 <tt/void DoPreviousMenu (void)/
425 This functions causes menu processor to go back one menu level. You should use it in menu
426 handler code to have the screen clean.
430 <tt/void GotoFirstMenu (void)/
432 This one jumps back to the topmost menu. If there is only menu and submenu it works the
433 same as <tt/DoPreviousMenu/.
435 <sect2>Icon Functions
437 Icons are working similar to menus except the fact that there is only one level. Icons are
438 defined as a screen area filled with a bitmap, but if you would setup icons and erase the
439 screen they are still active and clicking in the place where formerly an icon was will cause
440 an effect. Similary if you would setup icons and then turn them off with <tt/ClearMouseMode/
441 the bitmap will be still on the screen but clicking on it would not cause any action.
442 There is only one, but powerful icon function.
446 <tt/void DoIcons (struct icontab *myIconTab)/
448 This function initializes all icons that are present on the screen at once. For more information
449 look at <tt/Icons/ chapter in this manual.
453 This chapter covers the most powerful GEOS user interface function - <tt/DoDlgBox/.
459 <tt/char DoDlgBox (char *dialogString)/
461 DialogBox returns one byte. It can be the value of one of six standard icons (see <tt/gdlgbox.h/)
462 or whatever closing routine passes. Register <tt/r0L/ also contains this value.
464 Read structures chapter for the specs of the <tt/dialogString/.
466 <sect3>RstrFrmDialogue
468 <tt/char RstrFrmDialogue/
470 This function called from within DialogBox event immediately closes the DialogBox and returns
471 the owner ID (or whatever caller has in the .A register).
473 <sect2>GEOSLib extensions
475 To simplify usage of DoDlgBox from C I've wrote some help functions - wrappers for DoDlgBox,
476 with predefined data. In one word - these are standard DialogBoxes you can see in almost every
479 <sect3>DlgBoxYesNo, DlgBoxOkCancel, DlgBoxOk
481 <tt/char DlgBoxYesNo (char *line1, char *line2)/
483 <tt/char DlgBoxOkCancel (char *line1, char *line2)/
485 <tt/void DlgBoxOk (char *line1, char *line2)/
487 These function show two lines of text in standard-sized DialogBox. You can read the code of
488 pressed icon from return value. E.g. for <tt/DlgBoxYesNo/ it can only be <tt/YES/ or <tt/NO/.
490 <sect3>DlgBoxGetString
492 <tt/char DlgBoxGetString (char *string, char strlen, char *line1, char *line2)/
494 This function prompts user for entering a string of at most <tt/strlen/ characters. It is returned
495 in <tt/string/. The two given lines of text are shown above the input line. Please remember
496 that there is also <tt/CANCEL/ icon in the DialogBox and you should test if user confirmed his
497 input or gave up. The <tt/string/ is also shown so you can place default input there or remember
498 to place <tt/NULL/ at start.
500 <sect3>DlgBoxFileSelect
502 <tt/char DlgBoxFileSelect (char *class, char filetype, char *filename)/
504 This routine is the standard file selector. It can return <tt/OPEN/, <tt/CANCEL/ or disk error
505 on reading the directory or opening the disk.
506 There is also <tt/DISK/ icon shown, but it is handled internally. You pass as input parameters
507 <tt/filetype/ and pointer to string containing the first part of file's class. If this string is
508 empty (<tt/NULL/ at the start), then all files with given filetype will be shown.
510 At present this file selector handles only first 16 files of given type and supports only one
513 <sect1>Mouse, Sprites and Cursors
515 You will find here functions related to sprite and mouse drawing and handling.
517 <sect2>Mouse related functions
519 These cover mouse - as a general pointing device, but expect user to utilize as different devices
520 as digital or analog joystick, mouse, lightpen or koalapad (whatever it is).
522 <sect3>StartMouseMode
524 <tt/void StartMouseMode (void)/
526 This function initializes mouse vectors - <tt/mouseVector/ and <tt/mouseFaultVec/, and then
529 <sect3>ClearMouseMode
531 <tt/void ClearMouseMode (void)/
533 This function disables all mouse actitivies - icons and menus stop to respond to mouse events,
534 but they are not cleared from the screen.
536 <sect3>MouseUp and MouseOff
538 <tt/void MouseUp (void)/
540 <tt/void MouseOff (void)/
542 The first function turns the mouse pointer on. It will appear on next IRQ. The second one does
543 the opposite - it turns off the pointer, but its position is still updated by input driver.
547 <tt/char IsMseInRegion (struct window *myWindow)/
549 This function tests if mouse pointer is actually in given range of screen. See <tt/gsprite.h/ for
550 description of bits in return values - they describe the position in detail.
554 You are free to use any of the eight sprites, but keep in mind that sprite 0 is actually the mouse
555 pointer and sprite 1 can be overwritten when using text prompt. You don't have to worry about
556 40/80 column issues because GEOS128 has pretty good sprite emulator for VDC.
560 <tt/void DrawSprite (char sprite, char *mySprite)/
562 This function initializes the sprite data. <tt/mySprite/ is a 63-byte table with bitmap data, which
563 is copied to system sprite area (at <tt/sprpic/ - see <tt/gsym.h/). Hardware sprite registers are
564 not initialized and sprite is not yet visible.
568 <tt/void PosSprite (char sprite, struct pixel *myPixel)/
570 This function positions the sprite on the screen. Given coordinates are screen ones - they are
571 converted to sprite coordinates by GEOS. Due to this you cannot use this function to position your
572 sprite off the left or top to the screen.
574 <sect3>EnablSprite and DisablSprite
576 <tt/void EnablSprite (char sprite)/
578 <tt/void DisablSprite (char sprite)/
580 These two functions are responsible for making the sprite visible or not.
582 <sect2>Cursors and Console
584 <sect3>InitTextPrompt
586 <tt/void InitTextPrompt (char height)/
588 This function initializes sprite 1 for text prompt with given <tt/height/. This parameter can be in
591 <sect3>PromptOn and PromptOff
593 <tt/void PromptOn (struct pixel *myPixel)/
595 <tt/void PromptOff (void)/
597 The first function places text prompt in given place and enables blinking.
598 The second one is pretty self-explanatory.
602 <tt/char GetNextChar (void)/
604 This function gets next character from the keyboard queue. If the queue is empty it returns
605 <tt/NULL/, otherwise you receive true ASCII code of a character or value of special (function)
606 key. See <tt/gsprite.h/ for list of them.
610 This chapter covers slightly low-level disk routines. You should use them with care, because
611 you may easily corrupt data on disks. Also remember that contemporary GEOS supports many various
612 devices and sticking to 1541 track layout (e.g. expecting the directory on track 18) might be
615 For some purposes you might consider using <tt/dio.h/ interface to disk access. It is native.
617 All GEOS disk functions return error code in X register. In some cases this is returned by
618 GEOSLib function (if its type is <tt/char/), but in all cases last error is saved in <tt/__oserror/
619 location. If it is nonzero - an error occured. See <tt/gdisk.h/ for the list of possible errorcodes.
620 You need to include <tt/errno.h/ to get <tt/__oserror/, together with standard <tt/errno/. The
621 latter gives less verbose, but still usable information and can be used with <tt/strerror/.
622 Probably you will get more information using <tt/_stroserror/ in similar way.
624 For passing parameters use almost always pointer to your data e.g. <tt/ReadBuff (&myTrSe)/.
626 <sect2>Buffer functions
628 These functions are taking single data sector (256 bytes) to read or write on a disk.
630 <sect3>ReadBuff and Writebuff
632 <tt/char ReadBuff (struct tr_se *myTrSe)/
634 <tt/char WriteBuff (struct tr_se *myTrSe)/
636 These functions read and write sector placed at <tt/diskBlkBuf/.
638 <sect3>GetBlock and ReadBlock
640 <tt/char GetBlock (struct tr_se *myTrSe, char *buffer)/
642 <tt/char ReadBlock (struct tr_se *myTrSe, char *buffer)/
644 These two functions are reading a single block directly at 256 byte array placed at <tt/buffer/.
645 The difference between them is that <tt/GetBlock/ will initialize TurboDos in drive if it was not
646 enabled. <tt/ReadBlock/ assumes that it is already enabled thus being slightly faster.
648 <sect3>PutBlock, WriteBlock, VerWriteBlock
650 <tt/char PutBlock (struct tr_se *myTrSe, char *buffer)/
652 <tt/char WriteBlock (struct tr_se *myTrSe, char *buffer)/
654 <tt/char VerWriteBlock (struct tr_se *myTrSe, char *buffer)/
656 Similar to previous but needed for writting the disk. <tt/VerWriteBlock/ verifies the data after
657 writting. In case of error five tries are attempted before error code is returned.
659 <sect2>Directory header
661 Functions described here are operating on <tt/curDirHeader/ where current disk header is stored.
662 On larger capacity drives (than 1541) the second part of directory header in <tt/dir2Head/.
666 <tt/void GetPtrCurDkNm (char *diskName)/
668 This function fills given character string with the name of current disk. It is converted to C
669 standard - string is terminated with <tt/NULL/ character instead of code 160 as in Commodore DOS.
670 Note that passed pointer must point to an array of at least 17 bytes.
672 <sect3>GetDirHead and PutDirHead
674 <tt/char GetDirHead (void)/
676 <tt/char PutDirHead (void)/
678 These functions are reading and writting the directory header. You should use <tt/GetDirHead/ before
679 using any functions described below, and you should use <tt/PutDirHead/ to save the changes on the
680 disk. Otherwise they will be lost. Operating area is the <tt/curDirHead/.
684 <tt/int CalcBlksFree (void)/
686 This function returns the number of free blocks on current disk. It is counted using data in
687 <tt/curDirHead/ so you must initialize the disk before calling it.
691 <tt/char ChkDskGEOS (void)/
693 This functions checks <tt/curDirHead/ for GEOS Format identifier. It returns either true or false,
694 and also sets <tt/isGEOS/ properly. You must initialize the disk before using this.
698 <tt/char SetGEOSDisk (void)/
700 This function initializes disk for use with GEOS. It sets indicator in directory header and
701 allocates a sector for the directory of border files. You don't need to initialize the disk before
706 <tt/char FindBAMBit (struct tr_se *myTrSe)/
708 This function returns the bit value from BAM (Block Allocation Map) for given sector. The bit is
709 set if the sector is free to use. Returned value is always zero if the sector is already allocated.
710 In fact, this function could be used in a following way:
712 #define BlockInUse FindBAMBit
714 if (!BlockInUse(&myTrSe)) {
715 ... block not allocated ...
719 Anyway, I feel that this function is too low-level.
721 <sect3>BlkAlloc and NxtBlkAlloc
723 <tt/char BlkAlloc (struct tr_se output[&rsqb, int length)/
725 <tt/char NxtBlkAlloc (struct tr_se *myTrSe, struct tr_se output[&rsqb, int length)/
727 Both functions are allocating enough disk sectors to fit the number of <tt/length/ in them. You
728 will find output in <tt/output/ which is table of <tt/struct tr_se/. The last entry will have the
729 number of track equal to 0 and sector equal to 255. The simpliest way of using them is to use
730 predefined space in GEOS data space and pass <tt/fileTrScTab/, which is a predefined table.
732 The difference between those two is that <tt/NextBlkAlloc/ will start allocating from given sector,
733 and <tt/BlkAlloc/ starts from the first nonused sector.
735 You need to use <tt/PutDirHead/ later to save any changes in BAM.
739 <tt/char FreeBlock (struct tr_se *myTrSe)/
741 Simply deallocates a block in BAM. You need to update BAM with <tt/PutDirHead/.
745 <tt/struct tr_se SetNextFree (struct tr_se *myTrSe)/
747 This function finds the first free sector starting from given track and sector and allocates it.
748 It might return the same argument if the given block is not allocated. I wanted it to be type
749 clean, but it made usage a bit tricky. To assign a value to own <tt/struct tr_se/ you have to
750 cast both variables to <tt/int/. E.g.
754 (int)myTrSe=(int)SetNextFree(&otherTrSe);
757 In this example <tt/otherTrSe/ can be replaced by <tt/myTrSe/.
759 NOTE that you <em/must/ use casting to have correct values.
761 <sect2>Low-level disk IO
763 Functions described here are more usable in kernal or drivers code, less common in applications,
764 but who knows, maybe someone will need them.
766 <sect3>EnterTurbo, ExitTurbo, PurgeTurbo
768 <tt/void EnterTurbo (void)/
770 <tt/void ExitTurbo (void)/
772 <tt/void PurgeTurbo (void)/
774 These functions are interface to GEOS TurboDos feature which makes slow Commodore drives a bit
775 more usable. <tt/EnterTurbo/ enables TurboDos unless it is already enabled. If not, then you will
776 have to wait a bit to transfer TurboDos code into disk drive RAM. <tt/ExitTurbo/ disables TurboDos.
777 This is useful for sending some DOS commands for drive e.g. for formatting. Note that before any
778 interaction with Kernal in ROM you have to call <tt/InitForIO/. You don't have to worry about speed.
779 <tt/EnterTurbo/ will only enable TurboDos (no code transfer) if TurboDos was disabled with
780 <tt/ExitTurbo/. <tt/PurgeTurbo/ acts different from <tt/ExitTurbo/ - it not only disables TurboDos,
781 but also removes it from drive RAM (not quite true, but it works like that). After using
782 <tt/PurgeTurbo/ the next call to <tt/EnterTurbo/ will reload drive RAM.
784 <sect3>ChangeDiskDevice
786 <tt/char ChangeDiskDevice (char newDevice)/
788 This function changes logical number of current device (in fact drives only) with given one. It is
789 usable for swapping drives. There's no check if given <tt/newDevice/ already exist, so if you want
790 to change the logical number of drive 8 to 9 and you have drive number 9 then GEOS will probably
791 hang on disk access. Use safe, large numbers. Note that safe IEC range is 8-31.
793 <sect2>Disk Initialization
795 GEOS has two functions for initialization ('logging' as they say on CP\M) the disk.
798 <tt/char OpenDisk (void)/
800 This function initializes everything for a new disk. It loads and enables TurboDos if needed.
801 Then the disk is initialized with <tt/NewDisk/. Next, <tt/GetDirHead/ initializes <tt/curDirHead/.
802 Disk names are compared and if they differ then disk cache on REU is cleared. Finally format is
803 checked with <tt/ChkDkGEOS/ and disk name is updated in internal tables.
807 <tt/char NewDisk (void)/
809 This function is similar to DOS command I. It clears REU cache and enables TurboDos if needed.
813 This section cover GEOS file interface.
815 <sect2>Directory handling
817 Functions described here are common for SEQ and VLIR structures.
819 <sect3>Get1stDirEntry and GetNxtDirEntry
821 <tt/struct filehandle *Get1stDirEntry (void)/
823 <tt/struct filehandle *GetNxtDirEntry (void)/
825 These two functions are best suited for scanning whole directory for particular files. Note that
826 returned filehandles describes all file slots in the directory - even those with deleted files.
827 The return value can be obtained by casting both sides to <tt/int/ - as in <tt/SetNextFree/
828 function or read directly after call to those two functions from <tt/r5/. Current sector number
829 is in <tt/r1/ and sector data itself is in <tt/diskBlkBuf/.
833 <tt/char FindFile (char *fName)/
835 This function scans whole directory for the given filename. It returns either 0 (success) or 5
836 (FILE_NOT_FOUND, defined in <tt/gdisk.h/) or any other fatal disk read error. After successful
837 <tt/FindFile/ you will have <tt/struct filehandle/ at <tt/dirEntryBuf/ filled with file's data and
838 other registers set as described in <tt/GetNxtDirEntry/.
842 <tt/char FindFTypes (char *buffer, char fType, char fMaxNum, char *classTxt)/
844 This function scans directory and fills a table at <tt/buffer/ with <tt/char [17]/ entries.
845 <tt/fType/ is GEOS type of searched files and <tt/classTxt/ is a string for Class field in file
846 header. Class will match if given will be equal or shorter than that found in file's header block.
847 If you want just to find all files with given GEOS type you should pass empty string or <tt/NULL/ as
848 <tt/classTxt/. Be warned that for searching <tt/NON_GEOS/ files must pass <tt/NULL/ as <tt/classTxt/.
849 <tt/fMaxNum/ is the maximal number of found files, thus the <tt/buffer/ must
850 provide area of size equal to <tt/17 * fMaxNum/.
851 This function returns the number of found files, ranging from 0 to number passed as <tt/fMaxNum/.
852 Return value can be also restored from <tt/r7H/.
856 <tt/char DeleteFile (char *fName)/
858 This function deletes a file by its name. It works for SEQ and VLIR files.
862 <tt/char RenameFile (char *oldName, char *newName)/
864 I think it is obvious...
868 <tt/char GetFHdrInfo (struct filehandle *myFile)/
870 This function loads the file header into <tt/fileHeader/ buffer. Using after e.g. <tt/FindFile/
871 you can pass address of <tt/dirEntryBuf/.
873 <sect2>Common and SEQ structure
875 Functions described here are common for SEQ and VLIR structures because arguments passed are
876 starting track and sector which may point either to start of a chain for VLIR or data for SEQ.
880 <tt/char ReadFile (struct tr_se *myTrSe, char *buffer, int fLength)/
882 This function reads at most <tt/fLength/ bytes into <tt/buffer/ from chained sectors starting at
887 <tt/char ReadByte (void)/
889 This function returns next byte from a file. Before the first call to it you must load <tt/r5/
890 with <tt/NULL/, <tt/r4/ with sector buffer address and <tt/r1/ with track and sector of the
891 first block of a file.
892 Remember to not modify <tt/r1/, <tt/r4/ and <tt/r5/. These registers must be preserved between
893 calls to <tt/ReadByte/.
895 Returned value is valid only if there was no error. End of file is marked as <tt/BFR_OVERFLOW/
896 in <tt/__oserror/, this is set when trying to read one byte after the end of file, in this case
897 returned value is invalid.
901 <tt/char SaveFile (struct fileheader *myHeader)/
903 <tt/SaveFile/ will take care of everything needed to create a GEOS file, no matter VLIR of SEQ
904 structure. All you need to do is to place data in proper place and prepare a header which will
905 contain all information about a file.
907 You have to declare a <tt/struct fileheader/ and fill it with proper values. There is only one
908 difference - the first two bytes which are link to nonexistant next sector are replaced by a
909 pointer to the DOS filename of the file.
911 When saving files two most important fields in <tt/struct fileheader/ are <tt/fileheader.load_address/
912 and <tt/fileheader.end_address/.
916 <tt/char FreeFile (struct tr_se myTable[])/
918 This function deallocates all sectors contained in passed table.
922 <tt/char FollowChain(struct tr_se *myTrSe, char *buffer)/
924 This function fills a <tt/struct tr_se/ table at <tt/buffer/ with sector numbers for chain of
925 sectors starting with <tt/myTrSe/. You can pass such data (<tt/buffer/) to e.g. <tt/FreeFile/.
927 <sect2>VLIR structure
929 Here are informations about VLIR files (called later as RecordFile) and functions.
931 VLIR is a file which consists of up to 127 SEQ-like files called records. Each record is like one
932 SEQ structure file. Records are grouped together, described by common name - VLIR file name and
933 own number. Each record pointed by its number is described by starting track and sector numbers.
934 VLIR structures allow records to be empty (<tt/tr_se/ of such record is equal to <tt/{NULL,$ff}/),
935 or even non-exist (<tt/{NULL,NULL}/). Any other numbers represent starting track and sector of
938 In GEOS there can be only one file opened at a time. Upon opening VLIR file some information
939 about it are copied into memory. You can retrieve records table at <tt/fileTrScTab/ (table of
940 128 <tt/struct tr_se/) and from <tt/VLIRInfo/ (<tt/struct VLIR_info/.
941 E.g. size of whole VLIR file can be retrieved by reading <tt/VLIRInfo.fileSize/.
943 <sect3>OpenRecordFile
945 <tt/char OpenRecordFile (char *fName)/
947 This function finds and opens given file. An error is returned if file is not found or if it is not
948 in VLIR format. Information in <tt/VLIRInfo/ is initialized. VLIR track and sector table is
949 loaded at <tt/fileTrScTab/ and will be valid until call to <tt/CloseRecordFile/ so don't modify it.
950 You should <tt/PointRecord/ before trying to do something with file.
952 <sect3>CloseRecordFile
954 <tt/char CloseRecordFile (void)/
956 This function calls <tt/UpdateRecordFile/ and clears internal GEOS variables.
958 <sect3>UpdateRecordFile
960 <tt/char UpdateRecordFile (void)/
962 This function will check <tt/VLIRInfo.fileWritten/ flag and if it is set, then <tt/curDirHead/ is
963 updated along with size and date stamps in directory entry.
967 <tt/char PointRecord (char recordNumber)/
969 This function will setup internal variables (and <tt/VLIRInfo.curRecord/) and return the track and
970 sector of given record in <tt/r1/. Note that the data may not be valid (if record is non-existing
971 you will get 0,0 and if it is empty - 255, 0).
973 <sect3>NextRecord and PreviousRecord
975 <tt/char NextRecord (void)/
977 <tt/char PreviousRecord (void)/
979 These two work like <tt/PointRecord/. Names are self-explanatory.
983 <tt/char AppendRecord (void)/
985 This function will append an empty record ( pair of 255,0 ) to current VLIR track and sector
986 table. It will also set <tt/VLIRInfo.curRecord/ to its number.
990 <tt/char DeleteRecord (void)/
992 This function will remove current record from the table, and move all current+1 records one place
993 back (in the table). Note that there's no BAM update and you must call <tt/UpdateRecordFile/ to
998 <tt/char InsertRecord (void)/
1000 This function will insert an empty record in place of <tt/VLIRInfo.curRecord/ and move all following
1001 records in table one place forward (contents of <tt/VLIRInfo.curRecord/ after call to <tt/InsertRecord/
1002 can be found in <tt/VLIRInfo.curRecord + 1/).
1004 <sect3>ReadRecord and WriteRecord
1006 <tt/char ReadRecord (char *buffer, int fLength)/
1008 <tt/char WriteRecord (char *buffer, int fLength)/
1010 This function will load or save at most <tt/fLength/ bytes from currently pointed record into or from
1013 <sect1>Memory and Strings
1015 Functions covered in this section are common for whole C world - copying memory parts and
1016 strings is one of the main computer tasks. GEOS also has interface to do this. These functions
1017 are replacement for those like <tt/memset, memcpy, strcpy/ etc. from standard libraries.
1019 However some of them have slighty different calling convention (order of arguments to be specific),
1020 so please check their syntax here before direct replacing.
1022 Please note that the memory described as <em/strings/ are up to 255 characters (without
1023 counting the terminating <tt/NULL/), and <em/regions/ cover whole 64K of memory.
1027 <tt/void CopyString (char *dest, char *src)/
1029 This function copies string from <tt/src/ to <tt/dest/, until it reaches <tt/NULL/. <tt/NULL/
1034 <tt/char CmpString (char *s1, char *s2)/
1036 This function compares string <tt/s1/ to <tt/s2/ for equality - this is case sensitive, and both
1037 strings have to have the same length. It returns either <tt/true/ (non-zero) or <tt/false/ (zero).
1039 <sect2>CopyFString and CmpFString
1041 <tt/void CopyFString (char length, char *dest, char *src)/
1043 <tt/char CmpFString (char length, char *s1, char *s2)/
1045 These two are similar to <tt/CopyString/ and <tt/CmpString/ except the fact, that you provide
1046 the length of copied or compared strings. The strings can also contain several <tt/NULL/
1047 characters - they are not treated as delimiters.
1051 <tt/int CRC (char *src, int length)/
1053 This function calculates the CRC checksum for given memory range. I don't know if it is
1054 compatible with standard CRC routines.
1056 <sect2>FillRam and ClearRam
1058 <tt/void FillRam (char *dest, char value, int length)/
1060 <tt/void ClearRam (char *dest, int length)/
1062 Both functions are filling given memory range. <tt/ClearRam/ fills with <tt/NULLs/, while
1063 <tt/FillRam/ uses given <tt/value/. Be warned that these functions destroy <tt/r0, r1 and
1064 r2L/ registers. <tt/FillRam/ is an alias for <tt/memset/.
1068 <tt/void MoveData (char *dest, char *src, int length)/
1070 This functions copies one memory region to another. There are checks for overlap and the
1071 non-destructive method is chosen. Be warned that this function destroys contents of
1072 <tt/r0, r1 and r2/ registers. This is also alias for <tt/memcpy/
1076 <tt/void InitRam (char *table)/
1078 This function allows to initialize multiple memory locations with single bytes or strings.
1079 This is done with <tt/table/ where everything is defined. See structures chapter for description of
1080 <tt/InitRam's/ command string.
1082 <sect2>Stash, Fetch, Swap, and VerifyRAM
1084 <tt/void StashRAM (char bank, int length, char *reuAddress, char *cpuAddress)/
1086 <tt/void FetchRAM (char bank, int length, char *reuAddress, char *cpuAddress)/
1088 <tt/void SwapRAM (char bank, int length, char *reuAddress, char *cpuAddress)/
1090 <tt/ char VerifyRAM (char bank, int length, char *reuAddress, char *cpuAddress)/
1092 These functions are interface to REU - Ram Expansion Unit. I think that they are self-explanatory.
1093 You can check for REU presence by taking value of <tt/ramExpSize/.
1095 <sect1>Processes and Multitasking
1097 Weird? Not at all. GEOS has limited multitasking ability. You can set up a chain of functions
1098 called in specified intervals and you can put the main program to sleep without disturbing other
1099 tasks and making user interface unresponsive.
1101 <sect2>InitProcesses
1103 <tt/void InitProcesses (char number, struct process *processTab)/
1105 This is the main initialization routine. After calling it processes are set up, but not
1106 enabled. The parameters for <tt/InitProcesses/ are:
1108 <item><tt/number/ - number of processes
1109 <item><tt/processTab/ - table of <tt/struct process/, with size equal to <tt/number/
1112 Single task is described by entry in <tt/processTab/, it contains two values - <tt/pointer/ to
1113 task function and number of <tt/jiffies/ which describe the delay between calls to task. On PAL
1114 systems there are 50 jiffies per second, while on NTSC there are 60.
1116 The maximum number of tasks is 20. Be warned that GEOS doesn't check if parameters are valid and
1117 if <tt/processTab/ would be too large it would overwrite existing data in GEOS space.
1119 There's one important thing - the last entry in <tt/processTab/ has to be <tt/NULL,NULL/, so the
1120 maximum size of <tt/processTab/ is equal to 21.
1122 See description of <tt/process/ structure for more detailed discussion on this.
1124 <sect2>RestartProcess and EnableProcess
1126 <tt/void RestartProcess (char processNumber)/
1128 <tt/void EnableProcess (char processNumber)/
1130 These two functions start the task counter. <tt/RestartProcess/ for each process should be called
1131 after <tt/InitProcesses/, because it resets all flags and counters and it starts the counters.
1133 <tt/RestartProcess/ enables counters and sets their initial value to that given in <tt/processTab/.
1135 <tt/EnableProcess/ forces given process to execute by simulating the timer running out of time.
1137 <sect2>BlockProcess and UnBlockProcess
1139 <tt/void BlockProcess (char processNumber)/
1141 <tt/void UnBlockProcess (char processNumber)/
1143 <tt/BlockProcess/ disables the execution of given process, but this does not disable the timers.
1145 <tt/UnBlockProcess/ does the opposite.
1147 <sect2>FreezeProcess and UnFreezeProcess
1149 <tt/void FreezeProcess (char processNumber)/
1151 <tt/void UnFreezeProcess (char processNumber)/
1153 <tt/FreezeProcess/ disables timer for given process. <tt/UnFreezeProcess/ does the opposite.
1154 This is not equal to <tt/RestartProcess/ as timers are not filled with initial value.
1158 <tt/void Sleep (int jiffies)/
1160 This function is multitasking sleep - the program is halted, but it doesn't block other functions.
1161 The only argument here is the number of jiffies to wait until app will wake up.
1163 You can force to sleep not only the main application routine, but also processes-tasks. Be warned
1164 that the maximum number of sleeping functions is 20. If it would be larger it will overwrite
1165 parameters of already sleeping functions in GEOS kernal data space, leading to crash.
1167 <sect1>System Functions
1171 <tt/void FirstInit (void)/
1173 This function initializes some GEOS variables and mouse parameters. This is called on GEOS boot
1174 up. You shouldn't use this unless you know what you are doing.
1176 <sect2>InitForIO and DoneWithIO
1178 <tt/void InitForIO (void)/
1180 <tt/void DoneWithIO (void)/
1182 These functions are called by some disk routines. You should call them only if you want to
1183 do something with IO registers or call one of Kernal's routines.
1187 <tt/void MainLoop (void)/
1189 Returns control to the system. Any code between call to <tt/MainLoop/ and the end of current
1190 function will never be executed. When in <tt/MainLoop/ systems waits for your action - using
1191 icons, keyboard or menus to force some specific action from program. You have to define
1192 proper handlers before that.
1196 <tt/void EnterDeskTop (void)/
1198 Calling this function will instantly terminate your program and bring you back to DeskTop.
1199 WARNING! It is not an equivalent of <tt/exit()/, library destructors code and functions
1200 registered with <tt/atexit()/ will not be called. In fact, you should always use
1201 <tt/exit()/ instead.
1205 <tt/void ToBASIC (void)/
1207 This one is another way of finishing application - forcing GEOS to shutdown and exit to BASIC.
1208 I was considering whether to include it or not, but maybe someone will need it. Which is I doubt.
1209 It has the same dangerous features as <tt/EnterDeskTop/.
1213 <tt/void Panic (void)/
1215 This calls system's <tt/Panic/ handler - it shows dialog box with message
1217 System error at:xxxx
1219 where <tt/xxxx/ is last known execution address (caller). By default this is bound to <tt/BRK/
1220 instruction, but it might be usable in debugging as kind of <tt/assert/.
1222 System is halted after call to <tt/Panic/ which means that library destructors will not be
1223 called and some data may be lost (no wonder you're panicking).
1227 <tt/void CallRoutine (void *myFunct)/
1229 This is system caller routine. You need to provide pointer to a function and it will be immediately
1230 called, unless the pointer is equal to <tt/NULL/. This is the main functionality of this function -
1231 you don't need to check if the pointer is valid.
1233 <sect2>GetSerialNumber
1235 <tt/int GetSerialNumber (void)/
1237 This function returns the serial number of system. It might be used for copy-protection.
1238 However, please remember that the Free Software is a true power and you are using it
1243 <tt/char GetRandom (void)/
1245 This function returns a random number. It can be also read from <tt/random/ e.g.
1249 but by calling this function you are sure that the results will be always different.
1250 <tt/random/ is updated once a frame (50Hz PAL) and on every call to <tt/GetRandom/.
1252 Note that it is not the same as <tt/rand/ function from the standard library. <tt/GetRandom/
1253 will give you unpredictable results (if IRQs will occur between calls to it) while
1254 <tt/rand/ conforms to the standard and for given seed (<tt/srand/) it always returns with the
1255 same sequence of values.
1259 <tt/void SetDevice (char device)/
1261 This function sets current device to given. It might be used together with <tt/InitForIO/,
1262 <tt/DoneWithIO/ and some Kernal routines. Unless new device is a disk drive this only sets
1263 new value in <tt/curDevice/, in other case new disk driver is loaded from REU or internal RAM.
1267 <tt/char get_ostype (void)/
1269 This function returns GEOS Kernal version combined (by logical OR) with machine type. Read
1270 <tt/gsys.h/ for definitions of returned values.
1274 <tt/char get_tv (void)/
1276 This function returns PAL/NTSC flag combined (by logical OR) with 40/80 columns flag. This is
1277 not the best way to check if screen has 40 or 80 columns since PAL/NTSC check is always
1278 performed and it can take as long as full raster frame. If you just want to know if
1279 screen has 40 or 80 columns use expression <tt/graphMode & 0x80/ which returns <tt/0/ for
1280 40 columns and <tt/0x80/ for 80 columns. Remember that this parameter can be changed during
1281 runtime. It is unclear if this will work for GEOS 64 so you probably do not want to test
1282 anything if not running under GEOS128. Use <tt/get_ostype/ to check it. Read <tt/gsys.h/ for
1283 definitions of returned values.
1285 <sect>Library Structures
1287 To simplify usage and optimize passing parameters to functions I have declared several structures
1288 which describe most common objects. Some of these structures are bound to static addresses in
1289 GEOS data space ($8000-$8fff), so you can use their fields directly in optimized way.
1290 Please see <tt/gsym.h/ and find them. All structures are defined in <tt/gstruct.h/ and you may
1291 find also some comments there.
1293 <sect1>Graphics Structures
1297 One simple structure describing a point on the screen.
1301 This structure describes a font in one pointsize. There is current font - <tt/struct fontdesc/
1302 bound to <tt/curFontDesc/. You can also force GEOS to use your own fonts by calling
1303 <tt/LoadCharSet/. You just need to open a VLIR font file and load one record - one pointsize
1304 somewhere. At the start of this area you already have all data for <tt/fontdesc/ so you can
1305 pass a pointer to the load adress of that pointsize to <tt/LoadCharSet/.
1309 This widely used structure holds description of a region of the screen. It describes top-left and
1310 bottom-right corners of a window.
1314 Maybe the name isn't the best - it has nothing with <tt/DoIcons/ but with bitmap functions -
1315 <tt/BitmapUp/ for example. This structure holds parameters needed to properly decode and show
1316 a bitmap on the screen. Bitmap has to be encoded - if you have some non-GEOS bitmaps simply
1317 convert them to Photo Scraps - this is the format used by all GEOS bitmap functions - <tt/DoIcons/
1322 These structures describe click boxes (icons) that can be placed on screen or in a dialog box.
1326 This is the definition of a single click box. Please see <tt/gstruct.h/ for description of its fields.
1330 This is toplevel description of icons to be placed and enabled on the screen. This structure
1331 has following fields:
1333 <item><tt/char number/ - total number of icons declared here
1334 <item><tt/struct pixel mousepos/ - after finishing <tt/DoIcons/ mouse pointer will be placed in
1335 this point allowing you to have hint for user what is default action
1336 <item><tt/struct icondef tab[&rsqb/ - this table of size equal to <tt/icontab.number/ contains
1337 descriptions for all icons
1340 <sect1>File and Disk
1344 This simple structure holds track and sector number of something. Do not expect the track to be
1345 in range 1-35, as GEOS can support many various and weird devices. For example my C128 256K
1346 expansion is utilized as RAMDisk with layout of 4 tracks 128 sectors each. However assuming that
1347 track number equal to 0 is illegal might be wise.
1351 This is placeholder for file datestamp. This structure is also present in <tt/struct filehandle/.
1352 GEOS is not Y2K compliant, so if current file has in <tt/filehandle.date.year/ value less than 86
1353 you can safely assume that it is e.g. 2004 and not 1904.
1357 This is main file descriptor. It is either entry in the directory (returned from file functions)
1358 or its copy in <tt/dirEntryBuf/. This is optimized so you can safely get to the file's year e.g.
1359 by testing <tt/dirEntryBuf.date.year/ - it will be compiled to simple <tt/LDA, STA/.
1363 This structure holds fileheader description. You can load file's header into <tt/fileHeader/
1364 fixed area using <tt/GetFHdrInfo/. (note that <tt/fileHeader/ is a place in memory while
1365 <tt/fileheader/ is a structure).
1366 You will also need own fileheader for <tt/SaveFile/.
1368 <sect1>System Structures
1372 This structure is defined only for <tt/system_date/. It is slightly different from <tt/f_date/
1373 so I prepared this one. You can e.g. get or set current time using <tt/system_date.s_hour/ and
1374 <tt/system_date.s_minute/. Accesses to these will be optimized to simple <tt/LDA/ and <tt/STA/
1379 You should declare a table of that type to prepare data for <tt/InitProcesses/. The maximum number
1380 of processes is 20, and the last entry has to be equal to <tt/{NULL,NULL}/, so this table may hold
1381 only 21 entries. The first member of this structure (<tt/pointer/) holds the pointer to called
1382 function (void returning void), you will probably have to cast that pointer into int. The second
1383 field <tt/jiffies/ holds the amount of time between calls to that function. On PAL systems there
1384 are 50 jiffies per second, while NTSC have 60 of them.
1386 <sect1>Few thing in detail...
1388 GEOSLib uses cc65 non-ANSI extensions to easily initialize data in memory. This is done with a
1389 kind of array of unspecified length and unspecified type. Here is how it goes:
1391 void example = {
1392 (char)3, (unsigned)3, (char)0 };
1394 Which will be compiled to following string of bytes:
1401 As you see this way it is possible to define data of any type in any order. You must remember to
1402 cast each member to proper type.
1404 <sect2>DoMenu structure
1406 <tt/DoMenu/ is responsible for everything concerned with menu processing. Many, many GEOS programs
1407 are just initializing screen and menu and exit to <tt/MainLoop/. In GEOSLib it is the same as
1408 returning from <tt/main/ function without using <tt/exit(0)/.
1410 Menu is described by two types of data - menu descriptors and menu items. Descriptor contains
1411 information about following menu items, and items are containing names of entries and either
1412 pointers to functions to execute or, in case of nested menus, pointers to submenu descriptors.
1413 Note that submenu descriptor can be top-level descriptor, there's no difference in structure,
1414 just in the content.
1416 Here is how single descriptor looks like:
1418 void myMenu = {
1419 (char)top, (char)botom, // this is the size of the menubox
1420 (unsigned)left, (unsigned)right, // counting all items in current descriptor
1421 (char)number_of_items | type_of_menu, // number of following items ORed with
1422 // type of this menu, it can be either
1423 // HORIZONTAL or VERTICAL if you will have also bit 6 set then menu won't be closed
1424 // after moving mouse pointer outside the menubox. You can have at most 31 items.
1426 This is followed by <tt/number_of_items/ of following item description.
1429 "menuitemname", (char)item_type, (unsigned)pointer,
1430 "nextitemname", (char)item_type, (unsigned)pointer,
1432 "lastitemname", (char)item_type, (unsigned)pointer };
1433 // Note that there isn't ending <tt/NULL/ or something like that.
1435 <tt/pointer/ is a pointer to something, what it points for depends from <tt/item_type/. This one
1436 can have following values:
1438 <tt/MENU_ACTION/ - a function pointed by <tt/pointer/ will be called after clicking on menu item
1440 <tt/SUB_MENU/ - <tt/pointer/ points to next menu descriptor - a submenu
1442 Both of them can be ORed with <tt/DYN_SUB_MENU/ and then the <tt/pointer/ points to a function
1443 which will return in <tt/r0/ needed pointer (to function to execute or a submenu).
1445 For creating nested menus (you can have at most 8 levels of submenus) you need to declare such
1446 structure for each submenu and top level menu.
1448 <sect2>DoDlgBox command string
1450 <tt/DoDlgBox/ is together with <tt/DoMenu/ one of the most powerful routines in GEOS. It is
1451 responsible for creating dialog boxes, that is windows which task is to interact with user.
1452 Format of the command string is following:
1454 (window size and position)
1455 (commands and parameters)
1458 There is custom type defined for the command string: <tt/dlgBoxStr/.
1460 <sect3>Size and position
1462 The first element can be specified in two ways - by using default size and position or specifying
1463 own. The first case results in
1465 const dlgBoxStr example = {
1466 DB_DEFPOS (pattern_of_shadow),
1470 And the own size and position would be:
1472 const dlgBoxStr example = {
1473 DB_SETPOS (pattern, top, bottom, left, right)
1480 The next element of <tt/DoDlgBox/ command string are commands themselves. First six commands are
1481 default icons and the number of selected icon will be returned from window processor. The icons are
1482 <tt/OK, CANCEL, YES, NO, OPEN/, and <tt/DISK/. You can use predefined macros for use them, e.g.:
1485 DB_ICON(OK, DBI_X_0, DBI_Y_0),
1488 Note that the position is counted from top left corner of window, not entire screen and that the 'x'
1489 position is counted in cards (8-pixel) and not in pixels. This is true also for all following commands.
1490 <tt/DBI_X_0/ and <tt/DBI_Y_0/ are predefined (see <tt/gdlgbox.h/ for more), default positions
1491 which will make icons to appear on default window exactly where you would expect them.
1493 <tt/DB_TXTSTR (x, y, text)/ will cause to show given text in the window.
1495 <tt/DB_VARSTR (x, y, ptr)/ works as above, but here you are passing a pointer to a zero page location
1496 where the address of text is stored. This is useful for information windows where only text content
1497 is variable. Consider following:
1501 r15=(int)text; // in code just before call to DoDlgBox
1503 DB_VARSTR (TXT_LN_X, TXT_LN_1_Y, &r15),
1506 will cause to appear the word ``foo'' in the window, but you may store the pointer to any text in
1507 <tt/r15/ (in this case) before call to DoDlgBox.
1509 <tt/DB_GETSTR(x, y, ptr, length)/ - will add input from keyboard feature. <tt/ptr/ works as in
1510 previous example and points to place where text is to be stored. Note that the contents of this
1511 place will be shown upon creating window. <tt/length/ is the maximum number of characters to input.
1513 <tt/DB_SYSOPV(ptr)/ - this sets <tt/otherPressVec/ to given pointer. It is called on every keypress.
1515 <tt/DB_GRPHSTR(ptr)/ - data for this command is the pointer for <tt/GraphicsString/ commands.
1517 <tt/DB_GETFILES(x, y)/ - for standard window you should pass 4 for both x and y. This function
1518 draws file selection box and searches current drive for files. Before call to <tt/DoDlgBox/ you
1519 must load <tt/r7L/ with GEOS filetype of searched files and <tt/r10/ with class text. In <tt/r5/
1520 you have to load pointer to a <tt/char[17]/ where selected filename will be copied. It works
1521 like <tt/FindFTypes/ but is limited to first 16 files.
1523 <tt/DB_OPVEC(ptr)/ - this sets the new pointer for button press function, if you pass
1524 <tt/RstrFrmDialogue/ here you will cause the window to close after pressing mouse button.
1526 <tt/DB_USRICON(x, y, ptr)/ - places single user icon (click box) on window, <tt/ptr/ points at a
1527 <tt/struct icondef/ but fields <tt/x/ and <tt/y/ are not used here. You can have at most 8 click
1528 boxes in a window, this is internal limit of GEOS Kernal.
1530 <tt/DB_USRROUT(ptr)/ - this command causes to immediately call user routine pointed by <tt/ptr/.
1532 <sect2>GraphicsString command string
1534 <tt/GraphicsString/ is a very powerful routine to initialize whole screen at once. There are
1535 predefined macros for all commands, names are self-explanatory, see them in <tt/ggraph.h/. Last
1536 command have to be <tt/GSTR_END/. There is custom type defined for the command string: <tt/graphicStr/.
1538 Here is an example for clearing the screen:
1540 const graphicStr example = {
1543 RECTANGLETO(319,199)
1547 <sect2>InitRam table
1549 This type of data is used to initialize one or more bytes in many places at once. The format is
1552 void example = {
1553 (unsigned)address_to_store_values_at,
1554 (char)number_of_bytes_that_follow,
1555 (char)data,(char)data (...)
1556 (...) - more such definitions
1557 (unsigned)NULL - address of 0 ends the table