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. Note that
41 unlikely other platforms this implementation does not provide fullscreen capabilities, e.g.
42 you are on your own with checking last row and scrolling screen up etc. Color, line drawing and
43 clearing functions are disabled because color is not supported and line drawing art can be
44 easily done with graphics functions. Please note that a variable width font (to be specific:
45 current font, so you can load any font you like) is used so <tt/wherex, gotox/ family functions
46 will not always return the same values. In fact <tt/gotoxy/ sets current position to the place
47 you would expect on a normal 40x25 screen, not a position that would regard current font's
48 height. Both 40 and 80 columns modes are supported.
50 It is safe to use these standard includes: <tt/conio.h, dio.h, errno.h, geos.h, joystick.h,
51 mouse.h, stdlib.h, string.h/
53 I am an assembler programmer and GEOSLib was designed in such way that cc65 could emit the best
54 available code (well, the best as for machine :). Many of the <tt/void foo (void)/ functions are
55 just raw calls to Kernal (assembled just as <tt/jsr _foo/), look in <tt/gsym.h/, where you
56 will find many definitions of standard GEOS locations. Access to these addresses is optimized by
57 cc65 to simple <tt/lda/ and <tt/sta/. Don't be afraid to use the power of C.
61 You will not need c64 or c128 for development. The only hardware requirement is a PC capable of
62 runing cc65. You will however need c64 or c128 emulator and GEOS image disks (.d64) to test your
67 <item><em/cc65/ Excellent package containing C crosscompiler, crossassembler and linker, you
68 can get it from: <htmlurl url="http://www.von-bassewitz.de/uz/cc65/"
69 name="http://www.von-bassewitz.de/uz/cc65/">
70 <item><em/VICE/ This is portable C64, C128 and few other Commodore computers emulator, you
71 can obtain it from: <htmlurl url="http://www.cs.cmu.edu/~dsladic/vice/vice.html"
72 name="http://www.cs.cmu.edu/~dsladic/vice/vice.html">. VICE package contains
73 c1541 program that is able to convert/unconvert GEOS files to disk images.
74 <item><em/Star Commander/ This tool is only for DOS. You will need it for transferring
75 object files from PC to 1541. There's also one important ability of this
76 tool - it automatically un-converts .cvt files into GEOS native format on
78 <item><em/cbm4linux/ A Linux kernel module that allows for communication with 1541 and
79 other Commodore IEC bus drives. It can be replacement for Star Commander if
80 you want only to transfer files to a disk and uncovert using GEOS program for
81 this purpose. Check out: <htmlurl url="http://www.lb.shuttle.de/puffin/cbm4linux/"
82 name="http://www.lb.shuttle.de/puffin/cbm4linux">
85 VICE and cc65 are portable - they run on variety of platforms - DOS, Win32 and UNIX. GEOSLib only
88 <em/Update:/ starting from v2.5.0 GEOSLib is a part of cc65 package as its GEOS support.
92 I want to thank Uz for his cc65 package, Alexander Boyce for his excellent GEOS Programmer's
93 Reference Guide and BSW for GEOS.
95 GEOSLib is covered by the same license as cc65. You can find the whole text among documentation.
96 I would really appreciate if you would like to send me your comments, suggestions, questions,
97 changes, bug reports etc. I will also appreciate if you will just give me a sign that you are
98 using GEOSLib - not especially something big and important, mail me even if you are just playing
101 You can send postcards with hellos to:
103 Maciej Witkowiak, ul. Slowackiego 6/57, 77-400 ZLOTOW
107 e-mail: <tt/ytm@elysium.pl/
109 <sect>What have you got and what to do with it?
111 This chapter describes some rules you ought to obey, and how to use GEOSLib.
115 Think twice before you use standard C library function. In current implementation almost always
116 you will get better code using only <tt/geos.h/. This is constantly changing as standard
117 functions are becoming wrappers to native GEOS Kernal with the new releases.
119 Apart from this file, which merely describes only standard GEOS library functions, you should read
120 <tt/grc/ (GEOS resource compiler) documentation. There are informations about necessary resource
121 files (each GEOS application neeeds at least one) and the building process - what should be done
126 All in all, you just need to place
128 #include <geos.h>
130 on top of your source.
132 Please read cc65's documentation on how to compile C, assembler and link everything together.
134 GEOSLib building process isn't yet defined stable. Detailed information how to link everything
135 together is in separated file together with resource compiler documentation.
137 As a general rule read the sources of example programs and read the headers. These are the most
138 reliable sources of knowledge ;). You will also find there many C macros representing various
139 arguments passed to functions. Please use them. You will find your sources easier to understand,
140 and it will be easier to find bugs.
142 All types used in GEOSLib are <tt/unsigned/.
144 Screen coordinates are given in pixels unless stated differently.
146 <sect1>Notes on style
148 All programs start their execution on <tt/main/ function. Unlike plain C exiting from this function
149 doesn't mean end of program. GEOS is event-driven environment where applications are only executing
150 events, main loop is in kernal. <tt/main/ function should setup the screen, menus etc. and return.
151 Real end of the program should be called from event call, e.g. from menu item. You can force end of
152 program and return to DeskTop either by standard <tt/exit (0)/ function or by <tt/EnterDeskTop()/.
153 Currently they are almost the same (last minute note: don't use <tt/exit/ ever, it's broken right
156 Whenever possible use definitions from <tt/gsym.h/. The resulting code is translated by cc65 into
157 series of <tt/lda/ and <tt/sta/, so you can't do it better :-).
159 Don't hesitate to use library functions. Everything was written with size and speed in mind. In
160 fact many calls are just redirections to GEOS kernal which results in simple <tt/jsr/.
162 You might wonder why I have chosen sometimes weird order of arguments in functions. It is because
163 I wanted to avoid unnecessary pushing and popping arguments from stack. cc65 can pass single <tt/int/
164 through CPU registers.
166 Do not try to compile in strict ANSI mode. I'm using some cc65 extensions which are not available in
169 <sect>Library Functions
171 Functions here are sorted more or less in the way they appear in header files. This way I am able
172 to keep functions covering similar task near each other. All function names are identical to those
173 from <tt/geosSym/ file provided with GeoProgrammer package. Only my extensions to <tt/geosSym/
174 are covered by new names, but I tried to keep them in the naming convention.
178 This section covers drawing package of GEOS along with text output routines.
182 <tt/void SetPattern (char pattern)/
184 This function sets current pattern to given. There are 32 different patterns in GEOS. You can
185 see them together in the filling box in GeoPaint.
187 <sect2>GraphicsString
189 <tt/void GraphicsString (char *myGString)/
191 One of the more powerfull routines of GEOS. This function calls other graphic functions depending
192 on given command string. See structures chapter for more detailed description of the structure of it.
194 <sect2>Rectangle functions
196 Parameters to those functions are grouped in <tt/struct window drawWindow/. To speed up things and
197 reduce overhead this structure is glued to zero page locations, where all rectangle functions
198 expect their parameters. You can modify data directly (e.g. <tt/drawWindow.top=10/) or via
199 <tt/InitDrawWindow/ function. Contents of <tt/drawWindow/ are guaranteed not to change only when
200 using graphics functions. In other case you should keep your data in separate <tt/struct window/
201 and use <tt/InitDrawWindow/ before first call to rectangle functions.
203 <sect3>InitDrawWindow
205 <tt/void InitDrawWindow (struct window *myWindow)/
207 This function only copies contents of <tt/myWindow/ into system area of <tt/drawWindow/. Use it
208 if for some reason you have to keep window data out of zero page space.
212 <tt/void Rectangle (void)/
214 This draws on screen rectangle filled with current pattern.
216 <sect3>FrameRectangle
218 <tt/void FrameRectangle (char pattern)/
220 This one draws frame with given line pattern.
222 <sect3>InvertRectangle
224 <tt/void InvertRectangle (void)/
226 Just as the name says...
228 <sect3>ImprintRectangle and RecoverRectangle
230 <tt/void ImprintRectangle (void)/
232 <tt/void RecoverRectangle (void)/
234 These two functions are for copying parts of the screen to (<tt/Imprint/) and from (<tt/Recover/)
235 backbuffer of the screen. For example when drawing new menu box GEOS first uses
236 <tt/ImprintRectangle/ to save the area under the box, and restores it by <tt/RecoverRectangle/ upon
239 <sect2>Line Functions
241 GEOS drawing package is optimized so there are different functions for drawing vertical and
244 <sect3>HorizontalLine
246 <tt/void HorizontalLine (char pattern, char y, int xStart, int xEnd)/
248 This function draws horizontal line using given pattern - here it is a true bit pattern, not
249 pattern set by <tt/SetPattern/.
253 <tt/void InvertLine (char y, int xStart, int xEnd)/
255 There is only horizontal version.
259 <tt/void RecoverLine (char y, int xStart, int xEnd)/
261 This function recovers only one line. It is utilized by <tt/RecoverRectangle/. See its description
266 <tt/void VerticalLine (char pattern, char yStart, char yEnd, int x)/
268 This function draws vertical line using given pattern. Note that <tt/pattern/ is not a pattern
269 number as set in <tt/SetPattern/ but a true bit pattern.
273 <tt/void DrawLine (struct window *myWindow)/
275 <tt/top/ parameters of <tt/struct window/ describe the starting point of the line, while
276 <tt/bottom/ are for the ending point. Current pattern is used for drawing.
278 <sect2>Point Functions
280 Parameters to these two functions are passed by a pointer to own <tt/struct pixel/ filled with
285 <tt/void DrawPoint (struct pixel *myPixel)/
287 Draws single point on the screen, no matter what the current pattern is.
291 <tt/char TestPoint (struct pixel *myPixel)/
293 This function tests if given pixel is set and returns true or false.
295 <sect2>Character and string output
299 <tt/void PutChar (char character, char y, char x)/
301 This function outputs single character using current style and font to screen.
305 <tt/void PutString (char *myString, char y, int x)/
307 Same as <tt/PutChar/ except the fact that you can output whole <tt/NULL/-terminated string.
308 See <tt/ggraph.h/ for list of tokens that you can also place in the string - like <tt/CBOLDON/ or
313 <tt/void PutDecimal (char parameter, int value, char y, int x)/
315 This function converts <tt/value/ to its decimal representation and outputs it to the screen.
316 Depending on given <tt/parameter/ the string can be filled with zeroes (string always 5 characters
317 long) or not, to be left or right justified to given pixel. See <tt/ggraph.h/ for predefined
318 values for <tt/parameter/.
324 <tt/char GetCharWidth (char character)/
326 This function returns real width (in pixels) of given character with current font. It can be used
327 for counting the length of string on screen, allowing for indentation or justification.
331 <tt/void LoadCharSet (struct fontdesc *myFont)/
333 This function forces GEOS to use given font instead of own. <tt/myFont/ should be casted from
334 pointer to the start of area where was loaded record from font file (VLIR structure).
338 <tt/void UseSystemFont (void)/
340 This function forces GEOS to use built-in BSW font.
342 <sect2>Bitmap handling
344 I'm not quite sure how are these functions working (except <tt/BitmapUp/) so you should
345 probably look into library sources and compare it with your knowledge. Please let me know
346 if something is wrong or broken.
350 <tt/void BitmapUp (struct iconpic *myPic)/
352 This function unpacks the bitmap and places it on the screen - just as you set it in the
353 <tt/struct iconpic/ pointer to which you pass. See <tt/gstruct.h/ for description of this
354 structure. Note that you can only use packed GEOS bitmaps - simple Photo Scrap is in this format.
358 <tt/void BitmapClip (char skipLeft, char skipRight, int skipTop, struct iconpic *myPic)/
360 This function acts similar to <tt/BitmapUp/ but you can also define which parts of the bitmap are
361 to be drawn - you give the number of columns (8-pixel) to skip on the right and left of the bitmap,
362 and the number of rows to skip from the top if it.
366 <tt/void BitOtherClip (void *proc1, void *proc2, char skipLeft, char skip Right, int skipTop,
367 struct iconpic *myPic)/
369 Similar to the previous one with some extension. <tt/proc1/ is called before reading a byte (it
370 returns in .A next value), and <tt/proc2/ is called every time the parser reads a byte which is
371 not a piece of pattern (byte of code greater than 219). Both procedures should be written
372 separately in assembler and declared as <tt/__fastcall__/ returning char.
374 <sect1>Menus and Icons
376 Here you will find information about functions related with menus and icons.
380 Menus are essencial for GUI. GEOS can handle only one menu at a time, but each menu can call
381 another one, which results in submenu tree. There can be up to 8 menu levels, each one with up
384 Menus are initialized with <tt/DoMenu/ and then Kernal takes care for everything. Your code
385 (called from event handler) should be a function without parameters, returning void. You should
386 use <tt/DoPreviousMenu/ or <tt/GotoFirstMenu/ at least once in its code to have the screen clean.
390 <tt/void DoMenu (struct menu *myMenu)/
392 This function initializes GEOS menu processor and exits. See <tt/DoMenu structure/ for more
393 information about it. Know that many GEOS application just initializes the screen, menu and
394 exits to main Kernal loop, this proves the power of <tt/DoMenu/.
398 <tt/void ReDoMenu (void)/
400 This simply redraws the menu at lowest level. It works like calling <tt/DoMenu/ again with
405 <tt/void RecoverMenu (void)/
407 This function erases current menu from the screen. It doesn't change the menu level.
409 <sect3>RecoverAllMenus
411 <tt/void RecoverAllMenus (void)/
413 This calls <tt/RecoverMenu/ and erases all menus from the screen. Then the menu level is
416 <sect3>DoPreviousMenu
418 <tt/void DoPreviousMenu (void)/
420 This functions causes menu processor to go back one menu level. You should use it in menu
421 handler code to have the screen clean.
425 <tt/void GotoFirstMenu (void)/
427 This one jumps back to the topmost menu. If there is only menu and submenu it works the
428 same as <tt/DoPreviousMenu/.
432 Icons are working similar to menus except the fact that there is only one level. Icons are
433 defined as a screen area filled with a bitmap, but if you would setup icons and erase the
434 screen they are still active and clicking in the place where formerly an icon was will cause
435 an effect. Similary if you would setup icons and then turn them off with <tt/ClearMouseMode/
436 the bitmap will be still on the screen but clicking on it would not cause any action.
437 There is only one, but powerful icon function.
441 <tt/void DoIcons (struct icontab *myIconTab)/
443 This function initializes all icons that are present on the screen at once. For more information
444 look at <tt/Icons/ chapter in this manual.
448 This chapter covers the most powerful GEOS user interface function - <tt/DoDlgBox/.
454 <tt/char DoDlgBox (char *dialogString)/
456 DialogBox returns one byte. It can be the value of one of six standard icons (see <tt/gdlgbox.h/)
457 or whatever closing routine passes. Register <tt/r0L/ also contains this value.
459 Read structures chapter for the specs of the <tt/dialogString/.
461 <sect3>RstrFrmDialogue
463 <tt/char RstrFrmDialogue/
465 This function called from within DialogBox event immediately closes the DialogBox and returns
466 the owner ID (or whatever caller has in the .A register).
468 <sect2>GEOSLib extensions
470 To simplify usage of DoDlgBox from C I've wrote some help functions - wrappers for DoDlgBox,
471 with predefined data. In one word - these are standard DialogBoxes you can see in almost every
474 <sect3>DlgBoxYesNo, DlgBoxOkCancel, DlgBoxOk
476 <tt/char DlgBoxYesNo (char *line1, char *line2)/
478 <tt/char DlgBoxOkCancel (char *line1, char *line2)/
480 <tt/void DlgBoxOk (char *line1, char *line2)/
482 These function show two lines of text in standard-sized DialogBox. You can read the code of
483 pressed icon from return value. E.g. for <tt/DlgBoxYesNo/ it can only be <tt/YES/ or <tt/NO/.
485 <sect3>DlgBoxGetString
487 <tt/char DlgBoxGetString (char *string, char strlen, char *line1, char *line2)/
489 This function prompts user for entering a string of at most <tt/strlen/ characters. It is returned
490 in <tt/string/. The two given lines of text are shown above the input line. Please remember
491 that there is also <tt/CANCEL/ icon in the DialogBox and you should test if user confirmed his
492 input or gave up. The <tt/string/ is also shown so you can place default input there or remember
493 to place <tt/NULL/ at start.
495 <sect3>DlgBoxFileSelect
497 <tt/char DlgBoxFileSelect (char *class, char filetype, char *filename)/
499 This routine is the standard file selector. It can return <tt/OPEN/, <tt/CANCEL/ or disk error
500 on reading the directory or opening the disk.
501 There is also <tt/DISK/ icon shown, but it is handled internally. You pass as input parameters
502 <tt/filetype/ and pointer to string containing the first part of file's class. If this string is
503 empty (<tt/NULL/ at the start), then all files with given filetype will be shown.
505 At present this file selector handles only first 16 files of given type and supports only one
508 <sect1>Mouse, Sprites and Cursors
510 You will find here functions related to sprite and mouse drawing and handling.
512 <sect2>Mouse related functions
514 These cover mouse - as a general pointing device, but expect user to utilize as different devices
515 as digital or analog joystick, mouse, lightpen or koalapad (whatever it is).
517 <sect3>StartMouseMode
519 <tt/void StartMouseMode (void)/
521 This function initializes mouse vectors - <tt/mouseVector/ and <tt/mouseFaultVec/, and then
524 <sect3>ClearMouseMode
526 <tt/void ClearMouseMode (void)/
528 This function disables all mouse actitivies - icons and menus stop to respond to mouse events,
529 but they are not cleared from the screen.
531 <sect3>MouseUp and MouseOff
533 <tt/void MouseUp (void)/
535 <tt/void MouseOff (void)/
537 The first function turns the mouse pointer on. It will appear on next IRQ. The second one does
538 the opposite - it turns off the pointer, but its position is still updated by input driver.
542 <tt/char IsMseInRegion (struct window *myWindow)/
544 This function tests if mouse pointer is actually in given range of screen. See <tt/gsprite.h/ for
545 description of bits in return values - they describe the position in detail.
549 You are free to use any of the eight sprites, but keep in mind that sprite 0 is actually the mouse
550 pointer and sprite 1 can be overwritten when using text prompt. You don't have to worry about
551 40/80 column issues because GEOS128 has pretty good sprite emulator for VDC.
555 <tt/void DrawSprite (char sprite, char *mySprite)/
557 This function initializes the sprite data. <tt/mySprite/ is a 63-byte table with bitmap data, which
558 is copied to system sprite area (at <tt/sprpic/ - see <tt/gsym.h/). Hardware sprite registers are
559 not initialized and sprite is not yet visible.
563 <tt/void PosSprite (char sprite, struct pixel *myPixel)/
565 This function positions the sprite on the screen. Given coordinates are screen ones - they are
566 converted to sprite coordinates by GEOS. Due to this you cannot use this function to position your
567 sprite off the left or top to the screen.
569 <sect3>EnablSprite and DisablSprite
571 <tt/void EnablSprite (char sprite)/
573 <tt/void DisablSprite (char sprite)/
575 These two functions are responsible for making the sprite visible or not.
577 <sect2>Cursors and Console
579 <sect3>InitTextPrompt
581 <tt/void InitTextPrompt (char height)/
583 This function initializes sprite 1 for text prompt with given <tt/height/. This parameter can be in
586 <sect3>PromptOn and PromptOff
588 <tt/void PromptOn (struct pixel *myPixel)/
590 <tt/void PromptOff (void)/
592 The first function places text prompt in given place and enables blinking.
593 The second one is pretty self-explanatory.
597 <tt/char GetNextChar (void)/
599 This function gets next character from the keyboard queue. If the queue is empty it returns
600 <tt/NULL/, otherwise you receive true ASCII code of a character or value of special (function)
601 key. See <tt/gsprite.h/ for list of them.
605 This chapter covers slightly low-level disk routines. You should use them with care, because
606 you may easily corrupt data on disks. Also remember that contemporary GEOS supports many various
607 devices and sticking to 1541 track layout (e.g. expecting the directory on track 18) might be
610 For some purposes you might consider using <tt/dio.h/ interface to disk access. It is native.
612 All GEOS disk functions return error code in X register. In some cases this is returned by
613 GEOSLib function (if its type is <tt/char/), but in all cases last error is saved in <tt/__oserror/
614 location. If it is nonzero - an error occured. See <tt/gdisk.h/ for the list of possible errorcodes.
615 You need to include <tt/errno.h/ to get <tt/__oserror/, together with standard <tt/errno/. The
616 latter gives less verbose, but still usable information and can be used with <tt/strerror/.
618 For passing parameters use almost always pointer to your data e.g. <tt/ReadBuff (&myTrSe)/.
620 <sect2>Buffer functions
622 These functions are taking single data sector (256 bytes) to read or write on a disk.
624 <sect3>ReadBuff and Writebuff
626 <tt/char ReadBuff (struct tr_se *myTrSe)/
628 <tt/char WriteBuff (struct tr_se *myTrSe)/
630 These functions read and write sector placed at <tt/diskBlkBuf/.
632 <sect3>GetBlock and ReadBlock
634 <tt/char GetBlock (struct tr_se *myTrSe, char *buffer)/
636 <tt/char ReadBlock (struct tr_se *myTrSe, char *buffer)/
638 These two functions are reading a single block directly at 256 byte array placed at <tt/buffer/.
639 The difference between them is that <tt/GetBlock/ will initialize TurboDos in drive if it was not
640 enabled. <tt/ReadBlock/ assumes that it is already enabled thus being slightly faster.
642 <sect3>PutBlock, WriteBlock, VerWriteBlock
644 <tt/char PutBlock (struct tr_se *myTrSe, char *buffer)/
646 <tt/char WriteBlock (struct tr_se *myTrSe, char *buffer)/
648 <tt/char VerWriteBlock (struct tr_se *myTrSe, char *buffer)/
650 Similar to previous but needed for writting the disk. <tt/VerWriteBlock/ verifies the data after
651 writting. In case of error five tries are attempted before error code is returned.
653 <sect2>Directory header
655 Functions described here are operating on <tt/curDirHeader/ where current disk header is stored.
656 On larger capacity drives (than 1541) the second part of directory header in <tt/dir2Head/.
660 <tt/void GetPtrCurDkNm (char *diskName)/
662 This function fills given character string with the name of current disk. It is converted to C
663 standard - string is terminated with <tt/NULL/ character instead of code 160 as in Commodore DOS.
664 Note that passed pointer must point to an array of at least 17 bytes.
666 <sect3>GetDirHead and PutDirHead
668 <tt/char GetDirHead (void)/
670 <tt/char PutDirHead (void)/
672 These functions are reading and writting the directory header. You should use <tt/GetDirHead/ before
673 using any functions described below, and you should use <tt/PutDirHead/ to save the changes on the
674 disk. Otherwise they will be lost. Operating area is the <tt/curDirHead/.
678 <tt/int CalcBlksFree (void)/
680 This function returns the number of free blocks on current disk. It is counted using data in
681 <tt/curDirHead/ so you must initialize the disk before calling it.
685 <tt/char ChkDskGEOS (void)/
687 This functions checks <tt/curDirHead/ for GEOS Format identifier. It returns either true or false,
688 and also sets <tt/isGEOS/ properly. You must initialize the disk before using this.
692 <tt/char SetGEOSDisk (void)/
694 This function initializes disk for use with GEOS. It sets indicator in directory header and
695 allocates a sector for the directory of border files. You don't need to initialize the disk before
700 <tt/char FindBAMBit (struct tr_se *myTrSe)/
702 This function returns the bit value from BAM (Block Allocation Map) for given sector. The bit is
703 set if the sector is free to use. Returned value is always zero if the sector is already allocated.
704 In fact, this function could be used in a following way:
706 #define BlockInUse FindBAMBit
708 if (!BlockInUse(&myTrSe)) {
709 ... block not allocated ...
713 Anyway, I feel that this function is too low-level.
715 <sect3>BlkAlloc and NxtBlkAlloc
717 <tt/char BlkAlloc (struct tr_se output[&rsqb, int length)/
719 <tt/char NxtBlkAlloc (struct tr_se *myTrSe, struct tr_se output[&rsqb, int length)/
721 Both functions are allocating enough disk sectors to fit the number of <tt/length/ in them. You
722 will find output in <tt/output/ which is table of <tt/struct tr_se/. The last entry will have the
723 number of track equal to 0 and sector equal to 255. The simpliest way of using them is to use
724 predefined space in GEOS data space and pass <tt/fileTrScTab/, which is a predefined table.
726 The difference between those two is that <tt/NextBlkAlloc/ will start allocating from given sector,
727 and <tt/BlkAlloc/ starts from the first nonused sector.
729 You need to use <tt/PutDirHead/ later to save any changes in BAM.
733 <tt/char FreeBlock (struct tr_se *myTrSe)/
735 Simply deallocates a block in BAM. You need to update BAM with <tt/PutDirHead/.
739 <tt/struct tr_se SetNextFree (struct tr_se *myTrSe)/
741 This function finds the first free sector starting from given track and sector and allocates it.
742 It might return the same argument if the given block is not allocated. I wanted it to be type
743 clean, but it made usage a bit tricky. To assign a value to own <tt/struct tr_se/ you have to
744 cast both variables to <tt/int/. E.g.
748 (int)myTrSe=(int)SetNextFree(&otherTrSe);
751 In this example <tt/otherTrSe/ can be replaced by <tt/myTrSe/.
753 NOTE that you <em/must/ use casting to have correct values.
755 <sect2>Low-level disk IO
757 Functions described here are more usable in kernal or drivers code, less common in applications,
758 but who knows, maybe someone will need them.
760 <sect3>EnterTurbo, ExitTurbo, PurgeTurbo
762 <tt/void EnterTurbo (void)/
764 <tt/void ExitTurbo (void)/
766 <tt/void PurgeTurbo (void)/
768 These functions are interface to GEOS TurboDos feature which makes slow Commodore drives a bit
769 more usable. <tt/EnterTurbo/ enables TurboDos unless it is already enabled. If not, then you will
770 have to wait a bit to transfer TurboDos code into disk drive RAM. <tt/ExitTurbo/ disables TurboDos.
771 This is useful for sending some DOS commands for drive e.g. for formatting. Note that before any
772 interaction with Kernal in ROM you have to call <tt/InitForIO/. You don't have to worry about speed.
773 <tt/EnterTurbo/ will only enable TurboDos (no code transfer) if TurboDos was disabled with
774 <tt/ExitTurbo/. <tt/PurgeTurbo/ acts different from <tt/ExitTurbo/ - it not only disables TurboDos,
775 but also removes it from drive RAM (not quite true, but it works like that). After using
776 <tt/PurgeTurbo/ the next call to <tt/EnterTurbo/ will reload drive RAM.
778 <sect3>ChangeDiskDevice
780 <tt/char ChangeDiskDevice (char newDevice)/
782 This function changes logical number of current device (in fact drives only) with given one. It is
783 usable for swapping drives. There's no check if given <tt/newDevice/ already exist, so if you want
784 to change the logical number of drive 8 to 9 and you have drive number 9 then GEOS will probably
785 hang on disk access. Use safe, large numbers. Note that safe IEC range is 8-31.
787 <sect2>Disk Initialization
789 GEOS has two functions for initialization ('logging' as they say on CP\M) the disk.
792 <tt/char OpenDisk (void)/
794 This function initializes everything for a new disk. It loads and enables TurboDos if needed.
795 Then the disk is initialized with <tt/NewDisk/. Next, <tt/GetDirHead/ initializes <tt/curDirHead/.
796 Disk names are compared and if they differ then disk cache on REU is cleared. Finally format is
797 checked with <tt/ChkDkGEOS/ and disk name is updated in internal tables.
801 <tt/char NewDisk (void)/
803 This function is similar to DOS command I. It clears REU cache and enables TurboDos if needed.
807 This section cover GEOS file interface.
809 <sect2>Directory handling
811 Functions described here are common for SEQ and VLIR structures.
813 <sect3>Get1stDirEntry and GetNxtDirEntry
815 <tt/struct filehandle *Get1stDirEntry (void)/
817 <tt/struct filehandle *GetNxtDirEntry (void)/
819 These two functions are best suited for scanning whole directory for particular files. Note that
820 returned filehandles describes all file slots in the directory - even those with deleted files.
821 The return value can be obtained by casting both sides to <tt/int/ - as in <tt/SetNextFree/
822 function or read directly after call to those two functions from <tt/r5/. Current sector number
823 is in <tt/r1/ and sector data itself is in <tt/diskBlkBuf/.
827 <tt/char FindFile (char *fName)/
829 This function scans whole directory for the given filename. It returns either 0 (success) or 5
830 (FILE_NOT_FOUND, defined in <tt/gdisk.h/) or any other fatal disk read error. After successful
831 <tt/FindFile/ you will have <tt/struct filehandle/ at <tt/dirEntryBuf/ filled with file's data and
832 other registers set as described in <tt/GetNxtDirEntry/.
836 <tt/char FindFTypes (char *buffer, char fType, char fMaxNum, char *classTxt)/
838 This function scans directory and fills a table at <tt/buffer/ with <tt/char [17]/ entries.
839 <tt/fType/ is GEOS type of searched files and <tt/classTxt/ is a string for Class field in file
840 header. Class will match if given will be equal or shorter than that found in file's header block.
841 If you want just to find all files with given GEOS type you should pass empty string or <tt/NULL/ as
842 <tt/classTxt/. Be warned that for searching <tt/NON_GEOS/ files must pass <tt/NULL/ as <tt/classTxt/.
843 <tt/fMaxNum/ is the maximal number of found files, thus the <tt/buffer/ must
844 provide area of size equal to <tt/17 * fMaxNum/.
845 This function returns the number of found files, ranging from 0 to number passed as <tt/fMaxNum/.
846 Return value can be also restored from <tt/r7H/.
850 <tt/char DeleteFile (char *fName)/
852 This function deletes a file by its name. It works for SEQ and VLIR files.
856 <tt/char RenameFile (char *oldName, char *newName)/
858 I think it is obvious...
862 <tt/char GetFHdrInfo (struct filehandle *myFile)/
864 This function loads the file header into <tt/fileHeader/ buffer. Using after e.g. <tt/FindFile/
865 you can pass address of <tt/dirEntryBuf/.
867 <sect2>Common and SEQ structure
869 Functions described here are common for SEQ and VLIR structures because arguments passed are
870 starting track and sector which may point either to start of a chain for VLIR or data for SEQ.
874 <tt/char ReadFile (struct tr_se *myTrSe, char *buffer, int fLength)/
876 This function reads at most <tt/fLength/ bytes into <tt/buffer/ from chained sectors starting at
881 <tt/char ReadByte (void)/
883 This function returns next byte from a file. Before the first call to it you must load <tt/r5/
884 with <tt/NULL/, <tt/r4/ with sector buffer address and <tt/r1/ with track and sector of the
885 first block of a file.
886 Remember to not modify <tt/r1/, <tt/r4/ and <tt/r5/. These registers must be preserved between
887 calls to <tt/ReadByte/.
889 Returned value is valid only if there was no error. End of file is marked as <tt/BFR_OVERFLOW/
890 in <tt/__oserror/, this is set when trying to read one byte after the end of file, in this case
891 returned value is invalid.
895 <tt/char SaveFile (struct fileheader *myHeader)/
897 <tt/SaveFile/ will take care of everything needed to create a GEOS file, no matter VLIR of SEQ
898 structure. All you need to do is to place data in proper place and prepare a header which will
899 contain all information about a file.
901 You have to declare a <tt/struct fileheader/ and fill it with proper values. There is only one
902 difference - the first two bytes which are link to nonexistant next sector are replaced by a
903 pointer to the DOS filename of the file.
905 When saving files two most important fields in <tt/struct fileheader/ are <tt/fileheader.load_address/
906 and <tt/fileheader.end_address/.
910 <tt/char FreeFile (struct tr_se myTable[])/
912 This function deallocates all sectors contained in passed table.
916 <tt/char FollowChain(struct tr_se *myTrSe, char *buffer)/
918 This function fills a <tt/struct tr_se/ table at <tt/buffer/ with sector numbers for chain of
919 sectors starting with <tt/myTrSe/. You can pass such data (<tt/buffer/) to e.g. <tt/FreeFile/.
921 <sect2>VLIR structure
923 Here are informations about VLIR files (called later as RecordFile) and functions.
925 VLIR is a file which consists of up to 127 SEQ-like files called records. Each record is like one
926 SEQ structure file. Records are grouped together, described by common name - VLIR file name and
927 own number. Each record pointed by its number is described by starting track and sector numbers.
928 VLIR structures allow records to be empty (<tt/tr_se/ of such record is equal to <tt/{NULL,$ff}/),
929 or even non-exist (<tt/{NULL,NULL}/). Any other numbers represent starting track and sector of
932 In GEOS there can be only one file opened at a time. Upon opening VLIR file some information
933 about it are copied into memory. You can retrieve records table at <tt/fileTrScTab/ (table of
934 128 <tt/struct tr_se/) and from <tt/VLIRInfo/ (<tt/struct VLIR_info/.
935 E.g. size of whole VLIR file can be retrieved by reading <tt/VLIRInfo.fileSize/.
937 <sect3>OpenRecordFile
939 <tt/char OpenRecordFile (char *fName)/
941 This function finds and opens given file. An error is returned if file is not found or if it is not
942 in VLIR format. Information in <tt/VLIRInfo/ is initialized. VLIR track and sector table is
943 loaded at <tt/fileTrScTab/ and will be valid until call to <tt/CloseRecordFile/ so don't modify it.
944 You should <tt/PointRecord/ before trying to do something with file.
946 <sect3>CloseRecordFile
948 <tt/char CloseRecordFile (void)/
950 This function calls <tt/UpdateRecordFile/ and clears internal GEOS variables.
952 <sect3>UpdateRecordFile
954 <tt/char UpdateRecordFile (void)/
956 This function will check <tt/VLIRInfo.fileWritten/ flag and if it is set, then <tt/curDirHead/ is
957 updated along with size and date stamps in directory entry.
961 <tt/char PointRecord (char recordNumber)/
963 This function will setup internal variables (and <tt/VLIRInfo.curRecord/) and return the track and
964 sector of given record in <tt/r1/. Note that the data may not be valid (if record is non-existing
965 you will get 0,0 and if it is empty - 255, 0).
967 <sect3>NextRecord and PreviousRecord
969 <tt/char NextRecord (void)/
971 <tt/char PreviousRecord (void)/
973 These two work like <tt/PointRecord/. Names are self-explanatory.
977 <tt/char AppendRecord (void)/
979 This function will append an empty record ( pair of 255,0 ) to current VLIR track and sector
980 table. It will also set <tt/VLIRInfo.curRecord/ to its number.
984 <tt/char DeleteRecord (void)/
986 This function will remove current record from the table, and move all current+1 records one place
987 back (in the table). Note that there's no BAM update and you must call <tt/UpdateRecordFile/ to
992 <tt/char InsertRecord (void)/
994 This function will insert an empty record in place of <tt/VLIRInfo.curRecord/ and move all following
995 records in table one place forward (contents of <tt/VLIRInfo.curRecord/ after call to <tt/InsertRecord/
996 can be found in <tt/VLIRInfo.curRecord + 1/).
998 <sect3>ReadRecord and WriteRecord
1000 <tt/char ReadRecord (char *buffer, int fLength)/
1002 <tt/char WriteRecord (char *buffer, int fLength)/
1004 This function will load or save at most <tt/fLength/ bytes from currently pointed record into or from
1007 <sect1>Memory and Strings
1009 Functions covered in this section are common for whole C world - copying memory parts and
1010 strings is one of the main computer tasks. GEOS also has interface to do this. These functions
1011 are replacement for those like <tt/memset, memcpy, strcpy/ etc. from standard libraries.
1013 However some of them have slighty different calling convention (order of arguments to be specific),
1014 so please check their syntax here before direct replacing.
1016 Please note that the memory described as <em/strings/ are up to 255 characters (without
1017 counting the terminating <tt/NULL/), and <em/regions/ cover whole 64K of memory.
1021 <tt/void CopyString (char *dest, char *src)/
1023 This function copies string from <tt/src/ to <tt/dest/, until it reaches <tt/NULL/. <tt/NULL/
1028 <tt/char CmpString (char *s1, char *s2)/
1030 This function compares string <tt/s1/ to <tt/s2/ for equality - this is case sensitive, and both
1031 strings have to have the same length. It returns either <tt/true/ or <tt/false/.
1033 <sect2>CopyFString and CmpFString
1035 <tt/void CopyFString (char length, char *dest, char *src)/
1037 <tt/char CmpFString (char length, char *s1, char *s2)/
1039 These two are similar to <tt/CopyString/ and <tt/CmpString/ except the fact, that you provide
1040 the length of copied or compared strings. The strings can also contain several <tt/NULL/
1041 characters - they are not treated as delimiters.
1045 <tt/int CRC (char *src, int length)/
1047 This function calculates the CRC checksum for given memory range. I don't know if it is
1048 compatible with standard CRC routines.
1050 <sect2>FillRam and ClearRam
1052 <tt/void FillRam (char *dest, char value, int length)/
1054 <tt/void ClearRam (char *dest, int length)/
1056 Both functions are filling given memory range. <tt/ClearRam/ fills with <tt/NULLs/, while
1057 <tt/FillRam/ uses given <tt/value/. Be warned that these functions destroy <tt/r0, r1 and
1058 r2L/ registers. <tt/FillRam/ is an alias for <tt/memset/.
1062 <tt/void MoveData (char *dest, char *src, int length)/
1064 This functions copies one memory region to another. There are checks for overlap and the
1065 non-destructive method is chosen. Be warned that this function destroys contents of
1066 <tt/r0, r1 and r2/ registers. This is also alias for <tt/memcpy/
1070 <tt/void InitRam (char *table)/
1072 This function allows to initialize multiple memory locations with single bytes or strings.
1073 This is done with <tt/table/ where everything is defined. See structures chapter for description of
1074 <tt/InitRam's/ command string.
1076 <sect2>Stash, Fetch, Swap, and VerifyRAM
1078 <tt/void StashRAM (char bank, int length, char *reuAddress, char *cpuAddress)/
1080 <tt/void FetchRAM (char bank, int length, char *reuAddress, char *cpuAddress)/
1082 <tt/void SwapRAM (char bank, int length, char *reuAddress, char *cpuAddress)/
1084 <tt/ char VerifyRAM (char bank, int length, char *reuAddress, char *cpuAddress)/
1086 These functions are interface to REU - Ram Expansion Unit. I think that they are self-explanatory.
1087 You can check for REU presence by taking value of <tt/ramExpSize/.
1089 <sect1>Processes and Multitasking
1091 Weird? Not at all. GEOS has limited multitasking ability. You can set up a chain of functions
1092 called in specified intervals and you can put the main program to sleep without disturbing other
1093 tasks and making user interface unresponsive.
1095 <sect2>InitProcesses
1097 <tt/void InitProcesses (char number, struct process *processTab)/
1099 This is the main initialization routine. After calling it processes are set up, but not
1100 enabled. The parameters for <tt/InitProcesses/ are:
1102 <item><tt/number/ - number of processes
1103 <item><tt/processTab/ - table of <tt/struct process/, with size equal to <tt/number/
1106 Single task is described by entry in <tt/processTab/, it contains two values - <tt/pointer/ to
1107 task function and number of <tt/jiffies/ which describe the delay between calls to task. On PAL
1108 systems there are 50 jiffies per second, while on NTSC there are 60.
1110 The maximum number of tasks is 20. Be warned that GEOS doesn't check if parameters are valid and
1111 if <tt/processTab/ would be too large it would overwrite existing data in GEOS space.
1113 There's one important thing - the last entry in <tt/processTab/ has to be <tt/NULL,NULL/, so the
1114 maximum size of <tt/processTab/ is equal to 21.
1116 See description of <tt/process/ structure for more detailed discussion on this.
1118 <sect2>RestartProcess and EnableProcess
1120 <tt/void RestartProcess (char processNumber)/
1122 <tt/void EnableProcess (char processNumber)/
1124 These two functions start the task counter. <tt/RestartProcess/ for each process should be called
1125 after <tt/InitProcesses/, because it resets all flags and counters and it starts the counters.
1127 <tt/RestartProcess/ enables counters and sets their initial value to that given in <tt/processTab/.
1129 <tt/EnableProcess/ forces given process to execute by simulating the timer running out of time.
1131 <sect2>BlockProcess and UnBlockProcess
1133 <tt/void BlockProcess (char processNumber)/
1135 <tt/void UnBlockProcess (char processNumber)/
1137 <tt/BlockProcess/ disables the execution of given process, but this does not disable the timers.
1139 <tt/UnBlockProcess/ does the opposite.
1141 <sect2>FreezeProcess and UnFreezeProcess
1143 <tt/void FreezeProcess (char processNumber)/
1145 <tt/void UnFreezeProcess (char processNumber)/
1147 <tt/FreezeProcess/ disables timer for given process. <tt/UnFreezeProcess/ does the opposite.
1148 This is not equal to <tt/RestartProcess/ as timers are not filled with initial value.
1152 <tt/void Sleep (int jiffies)/
1154 This function is multitasking sleep - the program is halted, but it doesn't block other functions.
1155 The only argument here is the number of jiffies to wait until app will wake up.
1157 You can force to sleep not only the main application routine, but also processes-tasks. Be warned
1158 that the maximum number of sleeping functions is 20. If it would be larger it will overwrite
1159 parameters of already sleeping functions in GEOS kernal data space, leading to crash.
1165 <tt/void FirstInit (void)/
1167 This function initializes some GEOS variables and mouse parameters. This is called on GEOS boot
1168 up. You shouldn't use this unless you know what you are doing.
1170 <sect2>InitForIO and DoneWithIO
1172 <tt/void InitForIO (void)/
1174 <tt/void DoneWithIO (void)/
1176 These functions are called by some disk routines. You should call them only if you want to
1177 do something with IO registers or call one of Kernal's routines.
1181 <tt/void MainLoop (void)/
1183 Your programs exits to MainLoop upon exiting from <tt/main/, but you might need this function in
1184 menu and icon code. When in <tt/MainLoop/ systems waits for your action - using icons, keyboard
1185 or menus to force some specific action from program.
1189 <tt/void EnterDeskTop (void)/
1191 This is default exit code of your application. It is finish of <tt/exit()/, but you may need it
1192 in other places of application.
1196 <tt/void ToBASIC (void)/
1198 This one is another way of finishing application - forcing GEOS to shutdown and exit to BASIC.
1199 I was considering whether to include it or not, but maybe someone will need it. Which is I doubt.
1203 <tt/void Panic (void)/
1205 This calls system's <tt/Panic/ handler - it shows dialog box with message
1207 System error at:xxxx
1209 where <tt/xxxx/ is last known execution address (caller). By default this is bound to <tt/BRK/
1210 instruction, but it might be usable in debugging as kind of <tt/assert/.
1212 System is halted after call to <tt/Panic/.
1216 <tt/void CallRoutine (void *myFunct)/
1218 This is system caller routine. You need to provide pointer to a function and it will be immediately
1219 called, unless the pointer is equal to <tt/NULL/. This is the main functionality of this function -
1220 you need not to worry if the pointer is valid.
1222 <sect2>GetSerialNumber
1224 <tt/int GetSerialNumber (void)/
1226 This function returns the serial number of system. It might be used for copy-protection, but you
1227 shouldn't do this. Please remember that the Free Software is a true power.
1231 <tt/char GetRandom (void)/
1233 This function returns a random number. It can be also read from <tt/random/ e.g.
1237 but by calling this function you are sure that the results will be always different.
1238 <tt/random/ is updated once a frame (50Hz PAL) and on every call to <tt/GetRandom/
1242 <tt/void SetDevice (char device)/
1244 This function sets current device to given. It might be used together with <tt/InitForIO/,
1245 <tt/DoneWithIO/ and some Kernal routines. Unless new device is a disk drive this only sets
1246 new value in <tt/curDevice/, in other case new disk driver is loaded from REU or internal RAM.
1250 <tt/char get_ostype (void)/
1252 This function returns GEOS Kernal version combined (by logical OR) with machine type. Read
1253 <tt/gsys.h/ for definitions of returned values.
1257 <tt/char get_tv (void)/
1259 This function returns PAL/NTSC flag combined (by logical OR) with 40/80 columns flag. This is
1260 not the best way to check if screen has 40 or 80 columns since PAL/NTSC check is always
1261 performed and it can take as long as full raster frame. If you just want to know if
1262 screen has 40 or 80 columns use expression <tt/graphMode & 0x80/ which returns <tt/0/ for
1263 40 columns and <tt/0x80/ for 80 columns. Remember that this parameter can be changed during
1264 runtime. It is unclear if this will work for GEOS 64 so you probably do not want to test
1265 anything if not running under GEOS128. Use <tt/get_ostype/ to check it. Read <tt/gsys.h/ for
1266 definitions of returned values.
1268 <sect>Library Structures
1270 To simplify usage and optimize passing parameters to functions I have declared several structures
1271 which describe most common objects. Some of these structures are bound to static addresses in
1272 GEOS data space ($8000-$8fff), so you can use their fields directly in optimized way.
1273 Please see <tt/gsym.h/ and find them. All structures are defined in <tt/gstruct.h/ and you may
1274 find also some comments there.
1280 One simple structure describing a point on the screen.
1284 This structure describes a font in one pointsize. There is current font - <tt/struct fontdesc/
1285 bound to <tt/curFontDesc/. You can also force GEOS to use your own fonts by calling
1286 <tt/LoadCharSet/. You just need to open a VLIR font file and load one record - one pointsize
1287 somewhere. At the start of this area you already have all data for <tt/fontdesc/ so you can
1288 pass a pointer to the load adress of that pointsize to <tt/LoadCharSet/.
1292 This widely used structure holds description of a region of the screen. It describes top-left and
1293 bottom-right corners of a window.
1297 Maybe the name isn't the best - it has nothing with <tt/DoIcons/ but with bitmap functions -
1298 <tt/BitmapUp/ for example. This structure holds parameters needed to properly decode and show
1299 a bitmap on the screen. Bitmap has to be encoded - if you have some non-GEOS bitmaps simply
1300 convert them to Photo Scraps - this is the format used by all GEOS bitmap functions - <tt/DoIcons/
1305 These structures describe click boxes (icons) that can be placed on screen or in a dialog box.
1309 This is the definition of a single click box. Please see <tt/gstruct.h/ for description of its fields.
1313 This is toplevel description of icons to be placed and enabled on the screen. This structure
1314 has following fields:
1316 <item><tt/char number/ - total number of icons declared here
1317 <item><tt/struct pixel mousepos/ - after finishing <tt/DoIcons/ mouse pointer will be placed in
1318 this point allowing you to have hint for user what is default action
1319 <item><tt/struct icondef tab[&rsqb/ - this table of size equal to <tt/icontab.number/ contains
1320 descriptions for all icons
1323 <sect1>File and Disk
1327 This simple structure holds track and sector number of something. Do not expect the track to be
1328 in range 1-35, as GEOS can support many various and weird devices. For example my C128 256K
1329 expansion is utilized as RAMDisk with layout of 4 tracks 128 sectors each. However assuming that
1330 track number equal to 0 is illegal might be wise.
1334 This is placeholder for file datestamp. This structure is also present in <tt/struct filehandle/.
1335 GEOS is not Y2K compliant, so if current file has in <tt/filehandle.date.year/ value less than 86
1336 you can safely assume that it is e.g. 2004 and not 1904.
1340 This is main file descriptor. It is either entry in the directory (returned from file functions)
1341 or its copy in <tt/dirEntryBuf/. This is optimized so you can safely get to the file's year e.g.
1342 by testing <tt/dirEntryBuf.date.year/ - it will be compiled to simple <tt/LDA, STA/.
1346 This structure holds fileheader description. You can load file's header into <tt/fileHeader/
1347 fixed area using <tt/GetFHdrInfo/. (note that <tt/fileHeader/ is a place in memory while
1348 <tt/fileheader/ is a structure).
1349 You will also need own fileheader for <tt/SaveFile/.
1355 This structure is defined only for <tt/system_date/. It is slightly different from <tt/f_date/
1356 so I prepared this one. You can e.g. get or set current time using <tt/system_date.s_hour/ and
1357 <tt/system_date.s_minute/. Accesses to these will be optimized to simple <tt/LDA/ and <tt/STA/
1362 You should declare a table of that type to prepare data for <tt/InitProcesses/. The maximum number
1363 of processes is 20, and the last entry has to be equal to <tt/{NULL,NULL}/, so this table may hold
1364 only 21 entries. The first member of this structure (<tt/pointer/) holds the pointer to called
1365 function (void returning void), you will probably have to cast that pointer into int. The second
1366 field <tt/jiffies/ holds the amount of time between calls to that function. On PAL systems there
1367 are 50 jiffies per second, while NTSC have 60 of them.
1369 <sect1>Few thing in detail...
1371 GEOSLib uses cc65 non-ANSI extensions to easily initialize data in memory. This is done with a
1372 kind of array of unspecified length and unspecified type. Here is how it goes:
1374 void example = {
1375 (char)3, (unsigned)3, (char)0 };
1377 Which will be compiled to following string of bytes:
1384 As you see this way it is possible to define data of any type in any order. You must remember to
1385 cast each member to proper type.
1387 <sect2>DoMenu structure
1389 <tt/DoMenu/ is responsible for everything concerned with menu processing. Many, many GEOS programs
1390 are just initializing screen and menu and exit to <tt/MainLoop/. In GEOSLib it is the same as
1391 returning from <tt/main/ function without using <tt/exit(0)/.
1393 Menu is described by two types of data - menu descriptors and menu items. Descriptor contains
1394 information about following menu items, and items are containing names of entries and either
1395 pointers to functions to execute or, in case of nested menus, pointers to submenu descriptors.
1396 Note that submenu descriptor can be top-level descriptor, there's no difference in structure,
1397 just in the content.
1399 Here is how single descriptor looks like:
1401 void myMenu = {
1402 (char)top, (char)botom, // this is the size of the menubox
1403 (unsigned)left, (unsigned)right, // counting all items in current descriptor
1404 (char)number_of_items | type_of_menu, // number of following items ORed with
1405 // type of this menu, it can be either
1406 // HORIZONTAL or VERTICAL if you will have also bit 6 set then menu won't be closed
1407 // after moving mouse pointer outside the menubox. You can have at most 31 items.
1409 This is followed by <tt/number_of_items/ of following item description.
1412 "menuitemname", (char)item_type, (unsigned)pointer,
1413 "nextitemname", (char)item_type, (unsigned)pointer,
1415 "lastitemname", (char)item_type, (unsigned)pointer };
1416 // Note that there isn't ending <tt/NULL/ or something like that.
1418 <tt/pointer/ is a pointer to something, what it points for depends from <tt/item_type/. This one
1419 can have following values:
1421 <tt/MENU_ACTION/ - a function pointed by <tt/pointer/ will be called after clicking on menu item
1423 <tt/SUB_MENU/ - <tt/pointer/ points to next menu descriptor - a submenu
1425 Both of them can be ORed with <tt/DYN_SUB_MENU/ and then the <tt/pointer/ points to a function
1426 which will return in <tt/r0/ needed pointer (to function to execute or a submenu).
1428 For creating nested menus (you can have at most 8 levels of submenus) you need to declare such
1429 structure for each submenu and top level menu.
1431 <sect2>DoDlgBox command string
1433 <tt/DoDlgBox/ is together with <tt/DoMenu/ one of the most powerful routines in GEOS. It is
1434 responsible for creating dialog boxes, that is windows which task is to interact with user.
1435 Format of the command string is following:
1437 (window size and position)
1438 (commands and parameters)
1441 There is custom type defined for the command string: <tt/dlgBoxStr/.
1443 <sect3>Size and position
1445 The first element can be specified in two ways - by using default size and position or specifying
1446 own. The first case results in
1448 const dlgBoxStr example = {
1449 DB_DEFPOS (pattern_of_shadow),
1453 And the own size and position would be:
1455 const dlgBoxStr example = {
1456 DB_SETPOS (pattern, top, bottom, left, right)
1463 The next element of <tt/DoDlgBox/ command string are commands themselves. First six commands are
1464 default icons and the number of selected icon will be returned from window processor. The icons are
1465 <tt/OK, CANCEL, YES, NO, OPEN/, and <tt/DISK/. You can use predefined macros for use them, e.g.:
1468 DB_ICON(OK, DBI_X_0, DBI_Y_0),
1471 Note that the position is counted from top left corner of window, not entire screen and that the 'x'
1472 position is counted in cards (8-pixel) and not in pixels. This is true also for all following commands.
1473 <tt/DBI_X_0/ and <tt/DBI_Y_0/ are predefined (see <tt/gdlgbox.h/ for more), default positions
1474 which will make icons to appear on default window exactly where you would expect them.
1476 <tt/DB_TXTSTR (x, y, text)/ will cause to show given text in the window.
1478 <tt/DB_VARSTR (x, y, ptr)/ works as above, but here you are passing a pointer to a zero page location
1479 where the address of text is stored. This is useful for information windows where only text content
1480 is variable. Consider following:
1484 r15=(int)text; // in code just before call to DoDlgBox
1486 DB_VARSTR (TXT_LN_X, TXT_LN_1_Y, &r15),
1489 will cause to appear the word ``foo'' in the window, but you may store the pointer to any text in
1490 <tt/r15/ (in this case) before call to DoDlgBox.
1492 <tt/DB_GETSTR(x, y, ptr, length)/ - will add input from keyboard feature. <tt/ptr/ works as in
1493 previous example and points to place where text is to be stored. Note that the contents of this
1494 place will be shown upon creating window. <tt/length/ is the maximum number of characters to input.
1496 <tt/DB_SYSOPV(ptr)/ - this sets <tt/otherPressVec/ to given pointer. It is called on every keypress.
1498 <tt/DB_GRPHSTR(ptr)/ - data for this command is the pointer for <tt/GraphicsString/ commands.
1500 <tt/DB_GETFILES(x, y)/ - for standard window you should pass 4 for both x and y. This function
1501 draws file selection box and searches current drive for files. Before call to <tt/DoDlgBox/ you
1502 must load <tt/r7L/ with GEOS filetype of searched files and <tt/r10/ with class text. In <tt/r5/
1503 you have to load pointer to a <tt/char[17]/ where selected filename will be copied. It works
1504 like <tt/FindFTypes/ but is limited to first 16 files.
1506 <tt/DB_OPVEC(ptr)/ - this sets the new pointer for button press function, if you pass
1507 <tt/RstrFrmDialogue/ here you will cause the window to close after pressing mouse button.
1509 <tt/DB_USRICON(x, y, ptr)/ - places single user icon (click box) on window, <tt/ptr/ points at a
1510 <tt/struct icondef/ but fields <tt/x/ and <tt/y/ are not used here. You can have at most 8 click
1511 boxes in a window, this is internal limit of GEOS Kernal.
1513 <tt/DB_USRROUT(ptr)/ - this command causes to immediately call user routine pointed by <tt/ptr/.
1515 <sect2>GraphicsString command string
1517 <tt/GraphicsString/ is a very powerful routine to initialize whole screen at once. There are
1518 predefined macros for all commands, names are self-explanatory, see them in <tt/ggraph.h/. Last
1519 command have to be <tt/GSTR_END/. There is custom type defined for the command string: <tt/graphicStr/.
1521 Here is an example for clearing the screen:
1523 const graphicStr example = {
1526 RECTANGLETO(319,199)
1530 <sect2>InitRam table
1532 This type of data is used to initialize one or more bytes in many places at once. The format is
1535 void example = {
1536 (unsigned)address_to_store_values_at,
1537 (char)number_of_bytes_that_follow,
1538 (char)data,(char)data (...)
1539 (...) - more such definitions
1540 (unsigned)NULL - address of 0 ends the table