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 Think twice before you use standard C library function. In current implementation almost always
117 you will get better code using only <tt/geos.h/. This is constantly changing as standard
118 functions are becoming wrappers to native GEOS Kernal with the new releases.
120 Apart from this file, which merely describes only standard GEOS library functions, you should read
121 <tt/grc/ (GEOS resource compiler) documentation. There are informations about necessary resource
122 files (each GEOS application neeeds at least one) and the building process - what should be done
127 All in all, you just need to place
129 #include <geos.h>
131 on top of your source.
133 Please read cc65's documentation on how to compile C, assembler and link everything together.
135 GEOSLib building process isn't yet defined stable. Detailed information how to link everything
136 together is in separated file together with resource compiler documentation.
138 As a general rule read the sources of example programs and read the headers. These are the most
139 reliable sources of knowledge ;). You will also find there many C macros representing various
140 arguments passed to functions. Please use them. You will find your sources easier to understand,
141 and it will be easier to find bugs.
143 All types used in GEOSLib are <tt/unsigned/.
145 Screen coordinates are given in pixels unless stated differently.
147 <sect1>Notes on style
149 All programs start their execution on <tt/main/ function. Unlike plain C exiting from this function
150 doesn't mean end of program. GEOS is event-driven environment where applications are only executing
151 events, main loop is in kernal. <tt/main/ function should setup the screen, menus etc. and return.
152 Real end of the program should be called from event call, e.g. from menu item. You can force end of
153 program and return to DeskTop either by standard <tt/exit (0)/ function or by <tt/EnterDeskTop()/.
154 Currently they are almost the same.
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 bit pattern (not a pattern from GEOS palette).
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 from <tt/SetPattern/ 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 <tt/true/ (non-zero) or <tt/false/ (zero).
295 <sect2>Character and string output
299 <tt/cpputsxy (char x, char y, char *myString)/
301 <tt/cpputs (char *myString)/
303 Actually this is a part of <tt/conio/, but this function is non-standard. It is
304 a variety of <tt/cputs/ that will output string with proportional spacing, not
305 fixed like <tt/cputs/.
309 <tt/void PutChar (char character, char y, char x)/
311 This function outputs single character using current style and font to screen.
315 <tt/void PutString (char *myString, char y, int x)/
317 Same as <tt/PutChar/ except the fact that you can output whole <tt/NULL/-terminated string.
318 See <tt/ggraph.h/ for list of tokens that you can also place in the string - like <tt/CBOLDON/ or
323 <tt/void PutDecimal (char parameter, int value, char y, int x)/
325 This function converts <tt/value/ to its decimal representation and outputs it to the screen.
326 Depending on given <tt/parameter/ the string can be filled with zeroes (string always 5 characters
327 long) or not, to be left or right justified to given pixel. See <tt/ggraph.h/ for predefined
328 values for <tt/parameter/.
334 <tt/char GetCharWidth (char character)/
336 This function returns real width (in pixels) of given character with current font. It can be used
337 for counting the length of string on screen, allowing for indentation or justification.
341 <tt/void LoadCharSet (struct fontdesc *myFont)/
343 This function forces GEOS to use given font instead of own. <tt/myFont/ should be casted from
344 pointer to the start of area where was loaded record from font file (VLIR structure).
348 <tt/void UseSystemFont (void)/
350 This function forces GEOS to use built-in BSW font.
352 <sect2>Bitmap handling
354 I'm not quite sure how are these functions working (except <tt/BitmapUp/) so you should
355 probably look into library sources and compare it with your knowledge. Please let me know
356 if something is wrong or broken.
360 <tt/void BitmapUp (struct iconpic *myPic)/
362 This function unpacks the bitmap and places it on the screen - just as you set it in the
363 <tt/struct iconpic/ pointer to which you pass. See <tt/gstruct.h/ for description of this
364 structure. Note that you can only use packed GEOS bitmaps - simple Photo Scrap is in this format.
368 <tt/void BitmapClip (char skipLeft, char skipRight, int skipTop, struct iconpic *myPic)/
370 This function acts similar to <tt/BitmapUp/ but you can also define which parts of the bitmap are
371 to be drawn - you give the number of columns (8-pixel) to skip on the right and left of the bitmap,
372 and the number of rows to skip from the top if it.
376 <tt/void BitOtherClip (void *proc1, void *proc2, char skipLeft, char skip Right, int skipTop,
377 struct iconpic *myPic)/
379 Similar to the previous one with some extension. <tt/proc1/ is called before reading a byte (it
380 returns in .A next value), and <tt/proc2/ is called every time the parser reads a byte which is
381 not a piece of pattern (byte of code greater than 219). Both procedures should be written
382 separately in assembler and declared as <tt/__fastcall__/ returning char.
384 <sect1>Menus and Icons
386 Here you will find information about functions related with menus and icons.
390 Menus are essencial for GUI. GEOS can handle only one menu at a time, but each menu can call
391 another one, which results in submenu tree. There can be up to 8 menu levels, each one with up
394 Menus are initialized with <tt/DoMenu/ and then Kernal takes care for everything. Your code
395 (called from event handler) should be a function without parameters, returning void. You should
396 use <tt/DoPreviousMenu/ or <tt/GotoFirstMenu/ at least once in its code to have the screen clean.
400 <tt/void DoMenu (struct menu *myMenu)/
402 This function initializes GEOS menu processor and exits. See <tt/DoMenu structure/ for more
403 information about it. Know that many GEOS application just initializes the screen, menu and
404 exits to main Kernal loop, this proves the power of <tt/DoMenu/.
408 <tt/void ReDoMenu (void)/
410 This simply redraws the menu at lowest level. It works like calling <tt/DoMenu/ again with
415 <tt/void RecoverMenu (void)/
417 This function erases current menu from the screen. It doesn't change the menu level.
419 <sect3>RecoverAllMenus
421 <tt/void RecoverAllMenus (void)/
423 This calls <tt/RecoverMenu/ and erases all menus from the screen. Then the menu level is
426 <sect3>DoPreviousMenu
428 <tt/void DoPreviousMenu (void)/
430 This functions causes menu processor to go back one menu level. You should use it in menu
431 handler code to have the screen clean.
435 <tt/void GotoFirstMenu (void)/
437 This one jumps back to the topmost menu. If there is only menu and submenu it works the
438 same as <tt/DoPreviousMenu/.
440 <sect2>Icon Functions
442 Icons are working similar to menus except the fact that there is only one level. Icons are
443 defined as a screen area filled with a bitmap, but if you would setup icons and erase the
444 screen they are still active and clicking in the place where formerly an icon was will cause
445 an effect. Similary if you would setup icons and then turn them off with <tt/ClearMouseMode/
446 the bitmap will be still on the screen but clicking on it would not cause any action.
447 There is only one, but powerful icon function.
451 <tt/void DoIcons (struct icontab *myIconTab)/
453 This function initializes all icons that are present on the screen at once. For more information
454 look at <tt/Icons/ chapter in this manual.
458 This chapter covers the most powerful GEOS user interface function - <tt/DoDlgBox/.
464 <tt/char DoDlgBox (char *dialogString)/
466 DialogBox returns one byte. It can be the value of one of six standard icons (see <tt/gdlgbox.h/)
467 or whatever closing routine passes. Register <tt/r0L/ also contains this value.
469 Read structures chapter for the specs of the <tt/dialogString/.
471 <sect3>RstrFrmDialogue
473 <tt/char RstrFrmDialogue/
475 This function called from within DialogBox event immediately closes the DialogBox and returns
476 the owner ID (or whatever caller has in the .A register).
478 <sect2>GEOSLib extensions
480 To simplify usage of DoDlgBox from C I've wrote some help functions - wrappers for DoDlgBox,
481 with predefined data. In one word - these are standard DialogBoxes you can see in almost every
484 <sect3>DlgBoxYesNo, DlgBoxOkCancel, DlgBoxOk
486 <tt/char DlgBoxYesNo (char *line1, char *line2)/
488 <tt/char DlgBoxOkCancel (char *line1, char *line2)/
490 <tt/void DlgBoxOk (char *line1, char *line2)/
492 These function show two lines of text in standard-sized DialogBox. You can read the code of
493 pressed icon from return value. E.g. for <tt/DlgBoxYesNo/ it can only be <tt/YES/ or <tt/NO/.
495 <sect3>DlgBoxGetString
497 <tt/char DlgBoxGetString (char *string, char strlen, char *line1, char *line2)/
499 This function prompts user for entering a string of at most <tt/strlen/ characters. It is returned
500 in <tt/string/. The two given lines of text are shown above the input line. Please remember
501 that there is also <tt/CANCEL/ icon in the DialogBox and you should test if user confirmed his
502 input or gave up. The <tt/string/ is also shown so you can place default input there or remember
503 to place <tt/NULL/ at start.
505 <sect3>DlgBoxFileSelect
507 <tt/char DlgBoxFileSelect (char *class, char filetype, char *filename)/
509 This routine is the standard file selector. It can return <tt/OPEN/, <tt/CANCEL/ or disk error
510 on reading the directory or opening the disk.
511 There is also <tt/DISK/ icon shown, but it is handled internally. You pass as input parameters
512 <tt/filetype/ and pointer to string containing the first part of file's class. If this string is
513 empty (<tt/NULL/ at the start), then all files with given filetype will be shown.
515 At present this file selector handles only first 16 files of given type and supports only one
518 <sect1>Mouse, Sprites and Cursors
520 You will find here functions related to sprite and mouse drawing and handling.
522 <sect2>Mouse related functions
524 These cover mouse - as a general pointing device, but expect user to utilize as different devices
525 as digital or analog joystick, mouse, lightpen or koalapad (whatever it is).
527 <sect3>StartMouseMode
529 <tt/void StartMouseMode (void)/
531 This function initializes mouse vectors - <tt/mouseVector/ and <tt/mouseFaultVec/, and then
534 <sect3>ClearMouseMode
536 <tt/void ClearMouseMode (void)/
538 This function disables all mouse actitivies - icons and menus stop to respond to mouse events,
539 but they are not cleared from the screen.
541 <sect3>MouseUp and MouseOff
543 <tt/void MouseUp (void)/
545 <tt/void MouseOff (void)/
547 The first function turns the mouse pointer on. It will appear on next IRQ. The second one does
548 the opposite - it turns off the pointer, but its position is still updated by input driver.
552 <tt/char IsMseInRegion (struct window *myWindow)/
554 This function tests if mouse pointer is actually in given range of screen. See <tt/gsprite.h/ for
555 description of bits in return values - they describe the position in detail.
559 You are free to use any of the eight sprites, but keep in mind that sprite 0 is actually the mouse
560 pointer and sprite 1 can be overwritten when using text prompt. You don't have to worry about
561 40/80 column issues because GEOS128 has pretty good sprite emulator for VDC.
565 <tt/void DrawSprite (char sprite, char *mySprite)/
567 This function initializes the sprite data. <tt/mySprite/ is a 63-byte table with bitmap data, which
568 is copied to system sprite area (at <tt/sprpic/ - see <tt/gsym.h/). Hardware sprite registers are
569 not initialized and sprite is not yet visible.
573 <tt/void PosSprite (char sprite, struct pixel *myPixel)/
575 This function positions the sprite on the screen. Given coordinates are screen ones - they are
576 converted to sprite coordinates by GEOS. Due to this you cannot use this function to position your
577 sprite off the left or top to the screen.
579 <sect3>EnablSprite and DisablSprite
581 <tt/void EnablSprite (char sprite)/
583 <tt/void DisablSprite (char sprite)/
585 These two functions are responsible for making the sprite visible or not.
587 <sect2>Cursors and Console
589 <sect3>InitTextPrompt
591 <tt/void InitTextPrompt (char height)/
593 This function initializes sprite 1 for text prompt with given <tt/height/. This parameter can be in
596 <sect3>PromptOn and PromptOff
598 <tt/void PromptOn (struct pixel *myPixel)/
600 <tt/void PromptOff (void)/
602 The first function places text prompt in given place and enables blinking.
603 The second one is pretty self-explanatory.
607 <tt/char GetNextChar (void)/
609 This function gets next character from the keyboard queue. If the queue is empty it returns
610 <tt/NULL/, otherwise you receive true ASCII code of a character or value of special (function)
611 key. See <tt/gsprite.h/ for list of them.
615 This chapter covers slightly low-level disk routines. You should use them with care, because
616 you may easily corrupt data on disks. Also remember that contemporary GEOS supports many various
617 devices and sticking to 1541 track layout (e.g. expecting the directory on track 18) might be
620 For some purposes you might consider using <tt/dio.h/ interface to disk access. It is native.
622 All GEOS disk functions return error code in X register. In some cases this is returned by
623 GEOSLib function (if its type is <tt/char/), but in all cases last error is saved in <tt/__oserror/
624 location. If it is nonzero - an error occured. See <tt/gdisk.h/ for the list of possible errorcodes.
625 You need to include <tt/errno.h/ to get <tt/__oserror/, together with standard <tt/errno/. The
626 latter gives less verbose, but still usable information and can be used with <tt/strerror/.
627 Probably you will get more information using <tt/_stroserror/ in similar way.
629 For passing parameters use almost always pointer to your data e.g. <tt/ReadBuff (&myTrSe)/.
631 <sect2>Buffer functions
633 These functions are taking single data sector (256 bytes) to read or write on a disk.
635 <sect3>ReadBuff and Writebuff
637 <tt/char ReadBuff (struct tr_se *myTrSe)/
639 <tt/char WriteBuff (struct tr_se *myTrSe)/
641 These functions read and write sector placed at <tt/diskBlkBuf/.
643 <sect3>GetBlock and ReadBlock
645 <tt/char GetBlock (struct tr_se *myTrSe, char *buffer)/
647 <tt/char ReadBlock (struct tr_se *myTrSe, char *buffer)/
649 These two functions are reading a single block directly at 256 byte array placed at <tt/buffer/.
650 The difference between them is that <tt/GetBlock/ will initialize TurboDos in drive if it was not
651 enabled. <tt/ReadBlock/ assumes that it is already enabled thus being slightly faster.
653 <sect3>PutBlock, WriteBlock, VerWriteBlock
655 <tt/char PutBlock (struct tr_se *myTrSe, char *buffer)/
657 <tt/char WriteBlock (struct tr_se *myTrSe, char *buffer)/
659 <tt/char VerWriteBlock (struct tr_se *myTrSe, char *buffer)/
661 Similar to previous but needed for writting the disk. <tt/VerWriteBlock/ verifies the data after
662 writting. In case of error five tries are attempted before error code is returned.
664 <sect2>Directory header
666 Functions described here are operating on <tt/curDirHeader/ where current disk header is stored.
667 On larger capacity drives (than 1541) the second part of directory header in <tt/dir2Head/.
671 <tt/void GetPtrCurDkNm (char *diskName)/
673 This function fills given character string with the name of current disk. It is converted to C
674 standard - string is terminated with <tt/NULL/ character instead of code 160 as in Commodore DOS.
675 Note that passed pointer must point to an array of at least 17 bytes.
677 <sect3>GetDirHead and PutDirHead
679 <tt/char GetDirHead (void)/
681 <tt/char PutDirHead (void)/
683 These functions are reading and writting the directory header. You should use <tt/GetDirHead/ before
684 using any functions described below, and you should use <tt/PutDirHead/ to save the changes on the
685 disk. Otherwise they will be lost. Operating area is the <tt/curDirHead/.
689 <tt/int CalcBlksFree (void)/
691 This function returns the number of free blocks on current disk. It is counted using data in
692 <tt/curDirHead/ so you must initialize the disk before calling it.
696 <tt/char ChkDskGEOS (void)/
698 This functions checks <tt/curDirHead/ for GEOS Format identifier. It returns either true or false,
699 and also sets <tt/isGEOS/ properly. You must initialize the disk before using this.
703 <tt/char SetGEOSDisk (void)/
705 This function initializes disk for use with GEOS. It sets indicator in directory header and
706 allocates a sector for the directory of border files. You don't need to initialize the disk before
711 <tt/char FindBAMBit (struct tr_se *myTrSe)/
713 This function returns the bit value from BAM (Block Allocation Map) for given sector. The bit is
714 set if the sector is free to use. Returned value is always zero if the sector is already allocated.
715 In fact, this function could be used in a following way:
717 #define BlockInUse FindBAMBit
719 if (!BlockInUse(&myTrSe)) {
720 ... block not allocated ...
724 Anyway, I feel that this function is too low-level.
726 <sect3>BlkAlloc and NxtBlkAlloc
728 <tt/char BlkAlloc (struct tr_se output[&rsqb, int length)/
730 <tt/char NxtBlkAlloc (struct tr_se *myTrSe, struct tr_se output[&rsqb, int length)/
732 Both functions are allocating enough disk sectors to fit the number of <tt/length/ in them. You
733 will find output in <tt/output/ which is table of <tt/struct tr_se/. The last entry will have the
734 number of track equal to 0 and sector equal to 255. The simpliest way of using them is to use
735 predefined space in GEOS data space and pass <tt/fileTrScTab/, which is a predefined table.
737 The difference between those two is that <tt/NextBlkAlloc/ will start allocating from given sector,
738 and <tt/BlkAlloc/ starts from the first nonused sector.
740 You need to use <tt/PutDirHead/ later to save any changes in BAM.
744 <tt/char FreeBlock (struct tr_se *myTrSe)/
746 Simply deallocates a block in BAM. You need to update BAM with <tt/PutDirHead/.
750 <tt/struct tr_se SetNextFree (struct tr_se *myTrSe)/
752 This function finds the first free sector starting from given track and sector and allocates it.
753 It might return the same argument if the given block is not allocated. I wanted it to be type
754 clean, but it made usage a bit tricky. To assign a value to own <tt/struct tr_se/ you have to
755 cast both variables to <tt/int/. E.g.
759 (int)myTrSe=(int)SetNextFree(&otherTrSe);
762 In this example <tt/otherTrSe/ can be replaced by <tt/myTrSe/.
764 NOTE that you <em/must/ use casting to have correct values.
766 <sect2>Low-level disk IO
768 Functions described here are more usable in kernal or drivers code, less common in applications,
769 but who knows, maybe someone will need them.
771 <sect3>EnterTurbo, ExitTurbo, PurgeTurbo
773 <tt/void EnterTurbo (void)/
775 <tt/void ExitTurbo (void)/
777 <tt/void PurgeTurbo (void)/
779 These functions are interface to GEOS TurboDos feature which makes slow Commodore drives a bit
780 more usable. <tt/EnterTurbo/ enables TurboDos unless it is already enabled. If not, then you will
781 have to wait a bit to transfer TurboDos code into disk drive RAM. <tt/ExitTurbo/ disables TurboDos.
782 This is useful for sending some DOS commands for drive e.g. for formatting. Note that before any
783 interaction with Kernal in ROM you have to call <tt/InitForIO/. You don't have to worry about speed.
784 <tt/EnterTurbo/ will only enable TurboDos (no code transfer) if TurboDos was disabled with
785 <tt/ExitTurbo/. <tt/PurgeTurbo/ acts different from <tt/ExitTurbo/ - it not only disables TurboDos,
786 but also removes it from drive RAM (not quite true, but it works like that). After using
787 <tt/PurgeTurbo/ the next call to <tt/EnterTurbo/ will reload drive RAM.
789 <sect3>ChangeDiskDevice
791 <tt/char ChangeDiskDevice (char newDevice)/
793 This function changes logical number of current device (in fact drives only) with given one. It is
794 usable for swapping drives. There's no check if given <tt/newDevice/ already exist, so if you want
795 to change the logical number of drive 8 to 9 and you have drive number 9 then GEOS will probably
796 hang on disk access. Use safe, large numbers. Note that safe IEC range is 8-31.
798 <sect2>Disk Initialization
800 GEOS has two functions for initialization ('logging' as they say on CP\M) the disk.
803 <tt/char OpenDisk (void)/
805 This function initializes everything for a new disk. It loads and enables TurboDos if needed.
806 Then the disk is initialized with <tt/NewDisk/. Next, <tt/GetDirHead/ initializes <tt/curDirHead/.
807 Disk names are compared and if they differ then disk cache on REU is cleared. Finally format is
808 checked with <tt/ChkDkGEOS/ and disk name is updated in internal tables.
812 <tt/char NewDisk (void)/
814 This function is similar to DOS command I. It clears REU cache and enables TurboDos if needed.
818 This section cover GEOS file interface.
820 <sect2>Directory handling
822 Functions described here are common for SEQ and VLIR structures.
824 <sect3>Get1stDirEntry and GetNxtDirEntry
826 <tt/struct filehandle *Get1stDirEntry (void)/
828 <tt/struct filehandle *GetNxtDirEntry (void)/
830 These two functions are best suited for scanning whole directory for particular files. Note that
831 returned filehandles describes all file slots in the directory - even those with deleted files.
832 The return value can be obtained by casting both sides to <tt/int/ - as in <tt/SetNextFree/
833 function or read directly after call to those two functions from <tt/r5/. Current sector number
834 is in <tt/r1/ and sector data itself is in <tt/diskBlkBuf/.
838 <tt/char FindFile (char *fName)/
840 This function scans whole directory for the given filename. It returns either 0 (success) or 5
841 (FILE_NOT_FOUND, defined in <tt/gdisk.h/) or any other fatal disk read error. After successful
842 <tt/FindFile/ you will have <tt/struct filehandle/ at <tt/dirEntryBuf/ filled with file's data and
843 other registers set as described in <tt/GetNxtDirEntry/.
847 <tt/char FindFTypes (char *buffer, char fType, char fMaxNum, char *classTxt)/
849 This function scans directory and fills a table at <tt/buffer/ with <tt/char [17]/ entries.
850 <tt/fType/ is GEOS type of searched files and <tt/classTxt/ is a string for Class field in file
851 header. Class will match if given will be equal or shorter than that found in file's header block.
852 If you want just to find all files with given GEOS type you should pass empty string or <tt/NULL/ as
853 <tt/classTxt/. Be warned that for searching <tt/NON_GEOS/ files must pass <tt/NULL/ as <tt/classTxt/.
854 <tt/fMaxNum/ is the maximal number of found files, thus the <tt/buffer/ must
855 provide area of size equal to <tt/17 * fMaxNum/.
856 This function returns the number of found files, ranging from 0 to number passed as <tt/fMaxNum/.
857 Return value can be also restored from <tt/r7H/.
861 <tt/char DeleteFile (char *fName)/
863 This function deletes a file by its name. It works for SEQ and VLIR files.
867 <tt/char RenameFile (char *oldName, char *newName)/
869 I think it is obvious...
873 <tt/char GetFHdrInfo (struct filehandle *myFile)/
875 This function loads the file header into <tt/fileHeader/ buffer. Using after e.g. <tt/FindFile/
876 you can pass address of <tt/dirEntryBuf/.
878 <sect2>Common and SEQ structure
880 Functions described here are common for SEQ and VLIR structures because arguments passed are
881 starting track and sector which may point either to start of a chain for VLIR or data for SEQ.
885 <tt/char ReadFile (struct tr_se *myTrSe, char *buffer, int fLength)/
887 This function reads at most <tt/fLength/ bytes into <tt/buffer/ from chained sectors starting at
892 <tt/char ReadByte (void)/
894 This function returns next byte from a file. Before the first call to it you must load <tt/r5/
895 with <tt/NULL/, <tt/r4/ with sector buffer address and <tt/r1/ with track and sector of the
896 first block of a file.
897 Remember to not modify <tt/r1/, <tt/r4/ and <tt/r5/. These registers must be preserved between
898 calls to <tt/ReadByte/.
900 Returned value is valid only if there was no error. End of file is marked as <tt/BFR_OVERFLOW/
901 in <tt/__oserror/, this is set when trying to read one byte after the end of file, in this case
902 returned value is invalid.
906 <tt/char SaveFile (struct fileheader *myHeader)/
908 <tt/SaveFile/ will take care of everything needed to create a GEOS file, no matter VLIR of SEQ
909 structure. All you need to do is to place data in proper place and prepare a header which will
910 contain all information about a file.
912 You have to declare a <tt/struct fileheader/ and fill it with proper values. There is only one
913 difference - the first two bytes which are link to nonexistant next sector are replaced by a
914 pointer to the DOS filename of the file.
916 When saving files two most important fields in <tt/struct fileheader/ are <tt/fileheader.load_address/
917 and <tt/fileheader.end_address/.
921 <tt/char FreeFile (struct tr_se myTable[])/
923 This function deallocates all sectors contained in passed table.
927 <tt/char FollowChain(struct tr_se *myTrSe, char *buffer)/
929 This function fills a <tt/struct tr_se/ table at <tt/buffer/ with sector numbers for chain of
930 sectors starting with <tt/myTrSe/. You can pass such data (<tt/buffer/) to e.g. <tt/FreeFile/.
932 <sect2>VLIR structure
934 Here are informations about VLIR files (called later as RecordFile) and functions.
936 VLIR is a file which consists of up to 127 SEQ-like files called records. Each record is like one
937 SEQ structure file. Records are grouped together, described by common name - VLIR file name and
938 own number. Each record pointed by its number is described by starting track and sector numbers.
939 VLIR structures allow records to be empty (<tt/tr_se/ of such record is equal to <tt/{NULL,$ff}/),
940 or even non-exist (<tt/{NULL,NULL}/). Any other numbers represent starting track and sector of
943 In GEOS there can be only one file opened at a time. Upon opening VLIR file some information
944 about it are copied into memory. You can retrieve records table at <tt/fileTrScTab/ (table of
945 128 <tt/struct tr_se/) and from <tt/VLIRInfo/ (<tt/struct VLIR_info/.
946 E.g. size of whole VLIR file can be retrieved by reading <tt/VLIRInfo.fileSize/.
948 <sect3>OpenRecordFile
950 <tt/char OpenRecordFile (char *fName)/
952 This function finds and opens given file. An error is returned if file is not found or if it is not
953 in VLIR format. Information in <tt/VLIRInfo/ is initialized. VLIR track and sector table is
954 loaded at <tt/fileTrScTab/ and will be valid until call to <tt/CloseRecordFile/ so don't modify it.
955 You should <tt/PointRecord/ before trying to do something with file.
957 <sect3>CloseRecordFile
959 <tt/char CloseRecordFile (void)/
961 This function calls <tt/UpdateRecordFile/ and clears internal GEOS variables.
963 <sect3>UpdateRecordFile
965 <tt/char UpdateRecordFile (void)/
967 This function will check <tt/VLIRInfo.fileWritten/ flag and if it is set, then <tt/curDirHead/ is
968 updated along with size and date stamps in directory entry.
972 <tt/char PointRecord (char recordNumber)/
974 This function will setup internal variables (and <tt/VLIRInfo.curRecord/) and return the track and
975 sector of given record in <tt/r1/. Note that the data may not be valid (if record is non-existing
976 you will get 0,0 and if it is empty - 255, 0).
978 <sect3>NextRecord and PreviousRecord
980 <tt/char NextRecord (void)/
982 <tt/char PreviousRecord (void)/
984 These two work like <tt/PointRecord/. Names are self-explanatory.
988 <tt/char AppendRecord (void)/
990 This function will append an empty record ( pair of 255,0 ) to current VLIR track and sector
991 table. It will also set <tt/VLIRInfo.curRecord/ to its number.
995 <tt/char DeleteRecord (void)/
997 This function will remove current record from the table, and move all current+1 records one place
998 back (in the table). Note that there's no BAM update and you must call <tt/UpdateRecordFile/ to
1003 <tt/char InsertRecord (void)/
1005 This function will insert an empty record in place of <tt/VLIRInfo.curRecord/ and move all following
1006 records in table one place forward (contents of <tt/VLIRInfo.curRecord/ after call to <tt/InsertRecord/
1007 can be found in <tt/VLIRInfo.curRecord + 1/).
1009 <sect3>ReadRecord and WriteRecord
1011 <tt/char ReadRecord (char *buffer, int fLength)/
1013 <tt/char WriteRecord (char *buffer, int fLength)/
1015 This function will load or save at most <tt/fLength/ bytes from currently pointed record into or from
1018 <sect1>Memory and Strings
1020 Functions covered in this section are common for whole C world - copying memory parts and
1021 strings is one of the main computer tasks. GEOS also has interface to do this. These functions
1022 are replacement for those like <tt/memset, memcpy, strcpy/ etc. from standard libraries.
1024 However some of them have slighty different calling convention (order of arguments to be specific),
1025 so please check their syntax here before direct replacing.
1027 Please note that the memory described as <em/strings/ are up to 255 characters (without
1028 counting the terminating <tt/NULL/), and <em/regions/ cover whole 64K of memory.
1032 <tt/void CopyString (char *dest, char *src)/
1034 This function copies string from <tt/src/ to <tt/dest/, until it reaches <tt/NULL/. <tt/NULL/
1039 <tt/char CmpString (char *s1, char *s2)/
1041 This function compares string <tt/s1/ to <tt/s2/ for equality - this is case sensitive, and both
1042 strings have to have the same length. It returns either <tt/true/ (non-zero) or <tt/false/ (zero).
1044 <sect2>CopyFString and CmpFString
1046 <tt/void CopyFString (char length, char *dest, char *src)/
1048 <tt/char CmpFString (char length, char *s1, char *s2)/
1050 These two are similar to <tt/CopyString/ and <tt/CmpString/ except the fact, that you provide
1051 the length of copied or compared strings. The strings can also contain several <tt/NULL/
1052 characters - they are not treated as delimiters.
1056 <tt/int CRC (char *src, int length)/
1058 This function calculates the CRC checksum for given memory range. I don't know if it is
1059 compatible with standard CRC routines.
1061 <sect2>FillRam and ClearRam
1063 <tt/void FillRam (char *dest, char value, int length)/
1065 <tt/void ClearRam (char *dest, int length)/
1067 Both functions are filling given memory range. <tt/ClearRam/ fills with <tt/NULLs/, while
1068 <tt/FillRam/ uses given <tt/value/. Be warned that these functions destroy <tt/r0, r1 and
1069 r2L/ registers. <tt/FillRam/ is an alias for <tt/memset/.
1073 <tt/void MoveData (char *dest, char *src, int length)/
1075 This functions copies one memory region to another. There are checks for overlap and the
1076 non-destructive method is chosen. Be warned that this function destroys contents of
1077 <tt/r0, r1 and r2/ registers. This is also alias for <tt/memcpy/
1081 <tt/void InitRam (char *table)/
1083 This function allows to initialize multiple memory locations with single bytes or strings.
1084 This is done with <tt/table/ where everything is defined. See structures chapter for description of
1085 <tt/InitRam's/ command string.
1087 <sect2>Stash, Fetch, Swap, and VerifyRAM
1089 <tt/void StashRAM (char bank, int length, char *reuAddress, char *cpuAddress)/
1091 <tt/void FetchRAM (char bank, int length, char *reuAddress, char *cpuAddress)/
1093 <tt/void SwapRAM (char bank, int length, char *reuAddress, char *cpuAddress)/
1095 <tt/ char VerifyRAM (char bank, int length, char *reuAddress, char *cpuAddress)/
1097 These functions are interface to REU - Ram Expansion Unit. I think that they are self-explanatory.
1098 You can check for REU presence by taking value of <tt/ramExpSize/.
1100 <sect1>Processes and Multitasking
1102 Weird? Not at all. GEOS has limited multitasking ability. You can set up a chain of functions
1103 called in specified intervals and you can put the main program to sleep without disturbing other
1104 tasks and making user interface unresponsive.
1106 <sect2>InitProcesses
1108 <tt/void InitProcesses (char number, struct process *processTab)/
1110 This is the main initialization routine. After calling it processes are set up, but not
1111 enabled. The parameters for <tt/InitProcesses/ are:
1113 <item><tt/number/ - number of processes
1114 <item><tt/processTab/ - table of <tt/struct process/, with size equal to <tt/number/
1117 Single task is described by entry in <tt/processTab/, it contains two values - <tt/pointer/ to
1118 task function and number of <tt/jiffies/ which describe the delay between calls to task. On PAL
1119 systems there are 50 jiffies per second, while on NTSC there are 60.
1121 The maximum number of tasks is 20. Be warned that GEOS doesn't check if parameters are valid and
1122 if <tt/processTab/ would be too large it would overwrite existing data in GEOS space.
1124 There's one important thing - the last entry in <tt/processTab/ has to be <tt/NULL,NULL/, so the
1125 maximum size of <tt/processTab/ is equal to 21.
1127 See description of <tt/process/ structure for more detailed discussion on this.
1129 <sect2>RestartProcess and EnableProcess
1131 <tt/void RestartProcess (char processNumber)/
1133 <tt/void EnableProcess (char processNumber)/
1135 These two functions start the task counter. <tt/RestartProcess/ for each process should be called
1136 after <tt/InitProcesses/, because it resets all flags and counters and it starts the counters.
1138 <tt/RestartProcess/ enables counters and sets their initial value to that given in <tt/processTab/.
1140 <tt/EnableProcess/ forces given process to execute by simulating the timer running out of time.
1142 <sect2>BlockProcess and UnBlockProcess
1144 <tt/void BlockProcess (char processNumber)/
1146 <tt/void UnBlockProcess (char processNumber)/
1148 <tt/BlockProcess/ disables the execution of given process, but this does not disable the timers.
1150 <tt/UnBlockProcess/ does the opposite.
1152 <sect2>FreezeProcess and UnFreezeProcess
1154 <tt/void FreezeProcess (char processNumber)/
1156 <tt/void UnFreezeProcess (char processNumber)/
1158 <tt/FreezeProcess/ disables timer for given process. <tt/UnFreezeProcess/ does the opposite.
1159 This is not equal to <tt/RestartProcess/ as timers are not filled with initial value.
1163 <tt/void Sleep (int jiffies)/
1165 This function is multitasking sleep - the program is halted, but it doesn't block other functions.
1166 The only argument here is the number of jiffies to wait until app will wake up.
1168 You can force to sleep not only the main application routine, but also processes-tasks. Be warned
1169 that the maximum number of sleeping functions is 20. If it would be larger it will overwrite
1170 parameters of already sleeping functions in GEOS kernal data space, leading to crash.
1172 <sect1>System Functions
1176 <tt/void FirstInit (void)/
1178 This function initializes some GEOS variables and mouse parameters. This is called on GEOS boot
1179 up. You shouldn't use this unless you know what you are doing.
1181 <sect2>InitForIO and DoneWithIO
1183 <tt/void InitForIO (void)/
1185 <tt/void DoneWithIO (void)/
1187 These functions are called by some disk routines. You should call them only if you want to
1188 do something with IO registers or call one of Kernal's routines.
1192 <tt/void MainLoop (void)/
1194 Your programs exits to MainLoop upon exiting from <tt/main/, but you might need this function in
1195 menu and icon code. When in <tt/MainLoop/ systems waits for your action - using icons, keyboard
1196 or menus to force some specific action from program.
1200 <tt/void EnterDeskTop (void)/
1202 This is default exit code of your application. It is finish of <tt/exit()/, but you may need it
1203 in other places of application.
1207 <tt/void ToBASIC (void)/
1209 This one is another way of finishing application - forcing GEOS to shutdown and exit to BASIC.
1210 I was considering whether to include it or not, but maybe someone will need it. Which is I doubt.
1214 <tt/void Panic (void)/
1216 This calls system's <tt/Panic/ handler - it shows dialog box with message
1218 System error at:xxxx
1220 where <tt/xxxx/ is last known execution address (caller). By default this is bound to <tt/BRK/
1221 instruction, but it might be usable in debugging as kind of <tt/assert/.
1223 System is halted after call to <tt/Panic/.
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 need not to worry 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, but you
1238 shouldn't do this. Please remember that the Free Software is a true power.
1242 <tt/char GetRandom (void)/
1244 This function returns a random number. It can be also read from <tt/random/ e.g.
1248 but by calling this function you are sure that the results will be always different.
1249 <tt/random/ is updated once a frame (50Hz PAL) and on every call to <tt/GetRandom/.
1251 Note that it is not the same as <tt/rand/ function from the standard library. <tt/GetRandom/
1252 will give you unpredictable results (if IRQs will occur between calls to it) while
1253 <tt/rand/ conforms to the standard and for given seed (<tt/srand/) it always returns with the
1254 same sequence of values.
1258 <tt/void SetDevice (char device)/
1260 This function sets current device to given. It might be used together with <tt/InitForIO/,
1261 <tt/DoneWithIO/ and some Kernal routines. Unless new device is a disk drive this only sets
1262 new value in <tt/curDevice/, in other case new disk driver is loaded from REU or internal RAM.
1266 <tt/char get_ostype (void)/
1268 This function returns GEOS Kernal version combined (by logical OR) with machine type. Read
1269 <tt/gsys.h/ for definitions of returned values.
1273 <tt/char get_tv (void)/
1275 This function returns PAL/NTSC flag combined (by logical OR) with 40/80 columns flag. This is
1276 not the best way to check if screen has 40 or 80 columns since PAL/NTSC check is always
1277 performed and it can take as long as full raster frame. If you just want to know if
1278 screen has 40 or 80 columns use expression <tt/graphMode & 0x80/ which returns <tt/0/ for
1279 40 columns and <tt/0x80/ for 80 columns. Remember that this parameter can be changed during
1280 runtime. It is unclear if this will work for GEOS 64 so you probably do not want to test
1281 anything if not running under GEOS128. Use <tt/get_ostype/ to check it. Read <tt/gsys.h/ for
1282 definitions of returned values.
1284 <sect>Library Structures
1286 To simplify usage and optimize passing parameters to functions I have declared several structures
1287 which describe most common objects. Some of these structures are bound to static addresses in
1288 GEOS data space ($8000-$8fff), so you can use their fields directly in optimized way.
1289 Please see <tt/gsym.h/ and find them. All structures are defined in <tt/gstruct.h/ and you may
1290 find also some comments there.
1292 <sect1>Graphics Structures
1296 One simple structure describing a point on the screen.
1300 This structure describes a font in one pointsize. There is current font - <tt/struct fontdesc/
1301 bound to <tt/curFontDesc/. You can also force GEOS to use your own fonts by calling
1302 <tt/LoadCharSet/. You just need to open a VLIR font file and load one record - one pointsize
1303 somewhere. At the start of this area you already have all data for <tt/fontdesc/ so you can
1304 pass a pointer to the load adress of that pointsize to <tt/LoadCharSet/.
1308 This widely used structure holds description of a region of the screen. It describes top-left and
1309 bottom-right corners of a window.
1313 Maybe the name isn't the best - it has nothing with <tt/DoIcons/ but with bitmap functions -
1314 <tt/BitmapUp/ for example. This structure holds parameters needed to properly decode and show
1315 a bitmap on the screen. Bitmap has to be encoded - if you have some non-GEOS bitmaps simply
1316 convert them to Photo Scraps - this is the format used by all GEOS bitmap functions - <tt/DoIcons/
1321 These structures describe click boxes (icons) that can be placed on screen or in a dialog box.
1325 This is the definition of a single click box. Please see <tt/gstruct.h/ for description of its fields.
1329 This is toplevel description of icons to be placed and enabled on the screen. This structure
1330 has following fields:
1332 <item><tt/char number/ - total number of icons declared here
1333 <item><tt/struct pixel mousepos/ - after finishing <tt/DoIcons/ mouse pointer will be placed in
1334 this point allowing you to have hint for user what is default action
1335 <item><tt/struct icondef tab[&rsqb/ - this table of size equal to <tt/icontab.number/ contains
1336 descriptions for all icons
1339 <sect1>File and Disk
1343 This simple structure holds track and sector number of something. Do not expect the track to be
1344 in range 1-35, as GEOS can support many various and weird devices. For example my C128 256K
1345 expansion is utilized as RAMDisk with layout of 4 tracks 128 sectors each. However assuming that
1346 track number equal to 0 is illegal might be wise.
1350 This is placeholder for file datestamp. This structure is also present in <tt/struct filehandle/.
1351 GEOS is not Y2K compliant, so if current file has in <tt/filehandle.date.year/ value less than 86
1352 you can safely assume that it is e.g. 2004 and not 1904.
1356 This is main file descriptor. It is either entry in the directory (returned from file functions)
1357 or its copy in <tt/dirEntryBuf/. This is optimized so you can safely get to the file's year e.g.
1358 by testing <tt/dirEntryBuf.date.year/ - it will be compiled to simple <tt/LDA, STA/.
1362 This structure holds fileheader description. You can load file's header into <tt/fileHeader/
1363 fixed area using <tt/GetFHdrInfo/. (note that <tt/fileHeader/ is a place in memory while
1364 <tt/fileheader/ is a structure).
1365 You will also need own fileheader for <tt/SaveFile/.
1367 <sect1>System Structures
1371 This structure is defined only for <tt/system_date/. It is slightly different from <tt/f_date/
1372 so I prepared this one. You can e.g. get or set current time using <tt/system_date.s_hour/ and
1373 <tt/system_date.s_minute/. Accesses to these will be optimized to simple <tt/LDA/ and <tt/STA/
1378 You should declare a table of that type to prepare data for <tt/InitProcesses/. The maximum number
1379 of processes is 20, and the last entry has to be equal to <tt/{NULL,NULL}/, so this table may hold
1380 only 21 entries. The first member of this structure (<tt/pointer/) holds the pointer to called
1381 function (void returning void), you will probably have to cast that pointer into int. The second
1382 field <tt/jiffies/ holds the amount of time between calls to that function. On PAL systems there
1383 are 50 jiffies per second, while NTSC have 60 of them.
1385 <sect1>Few thing in detail...
1387 GEOSLib uses cc65 non-ANSI extensions to easily initialize data in memory. This is done with a
1388 kind of array of unspecified length and unspecified type. Here is how it goes:
1390 void example = {
1391 (char)3, (unsigned)3, (char)0 };
1393 Which will be compiled to following string of bytes:
1400 As you see this way it is possible to define data of any type in any order. You must remember to
1401 cast each member to proper type.
1403 <sect2>DoMenu structure
1405 <tt/DoMenu/ is responsible for everything concerned with menu processing. Many, many GEOS programs
1406 are just initializing screen and menu and exit to <tt/MainLoop/. In GEOSLib it is the same as
1407 returning from <tt/main/ function without using <tt/exit(0)/.
1409 Menu is described by two types of data - menu descriptors and menu items. Descriptor contains
1410 information about following menu items, and items are containing names of entries and either
1411 pointers to functions to execute or, in case of nested menus, pointers to submenu descriptors.
1412 Note that submenu descriptor can be top-level descriptor, there's no difference in structure,
1413 just in the content.
1415 Here is how single descriptor looks like:
1417 void myMenu = {
1418 (char)top, (char)botom, // this is the size of the menubox
1419 (unsigned)left, (unsigned)right, // counting all items in current descriptor
1420 (char)number_of_items | type_of_menu, // number of following items ORed with
1421 // type of this menu, it can be either
1422 // HORIZONTAL or VERTICAL if you will have also bit 6 set then menu won't be closed
1423 // after moving mouse pointer outside the menubox. You can have at most 31 items.
1425 This is followed by <tt/number_of_items/ of following item description.
1428 "menuitemname", (char)item_type, (unsigned)pointer,
1429 "nextitemname", (char)item_type, (unsigned)pointer,
1431 "lastitemname", (char)item_type, (unsigned)pointer };
1432 // Note that there isn't ending <tt/NULL/ or something like that.
1434 <tt/pointer/ is a pointer to something, what it points for depends from <tt/item_type/. This one
1435 can have following values:
1437 <tt/MENU_ACTION/ - a function pointed by <tt/pointer/ will be called after clicking on menu item
1439 <tt/SUB_MENU/ - <tt/pointer/ points to next menu descriptor - a submenu
1441 Both of them can be ORed with <tt/DYN_SUB_MENU/ and then the <tt/pointer/ points to a function
1442 which will return in <tt/r0/ needed pointer (to function to execute or a submenu).
1444 For creating nested menus (you can have at most 8 levels of submenus) you need to declare such
1445 structure for each submenu and top level menu.
1447 <sect2>DoDlgBox command string
1449 <tt/DoDlgBox/ is together with <tt/DoMenu/ one of the most powerful routines in GEOS. It is
1450 responsible for creating dialog boxes, that is windows which task is to interact with user.
1451 Format of the command string is following:
1453 (window size and position)
1454 (commands and parameters)
1457 There is custom type defined for the command string: <tt/dlgBoxStr/.
1459 <sect3>Size and position
1461 The first element can be specified in two ways - by using default size and position or specifying
1462 own. The first case results in
1464 const dlgBoxStr example = {
1465 DB_DEFPOS (pattern_of_shadow),
1469 And the own size and position would be:
1471 const dlgBoxStr example = {
1472 DB_SETPOS (pattern, top, bottom, left, right)
1479 The next element of <tt/DoDlgBox/ command string are commands themselves. First six commands are
1480 default icons and the number of selected icon will be returned from window processor. The icons are
1481 <tt/OK, CANCEL, YES, NO, OPEN/, and <tt/DISK/. You can use predefined macros for use them, e.g.:
1484 DB_ICON(OK, DBI_X_0, DBI_Y_0),
1487 Note that the position is counted from top left corner of window, not entire screen and that the 'x'
1488 position is counted in cards (8-pixel) and not in pixels. This is true also for all following commands.
1489 <tt/DBI_X_0/ and <tt/DBI_Y_0/ are predefined (see <tt/gdlgbox.h/ for more), default positions
1490 which will make icons to appear on default window exactly where you would expect them.
1492 <tt/DB_TXTSTR (x, y, text)/ will cause to show given text in the window.
1494 <tt/DB_VARSTR (x, y, ptr)/ works as above, but here you are passing a pointer to a zero page location
1495 where the address of text is stored. This is useful for information windows where only text content
1496 is variable. Consider following:
1500 r15=(int)text; // in code just before call to DoDlgBox
1502 DB_VARSTR (TXT_LN_X, TXT_LN_1_Y, &r15),
1505 will cause to appear the word ``foo'' in the window, but you may store the pointer to any text in
1506 <tt/r15/ (in this case) before call to DoDlgBox.
1508 <tt/DB_GETSTR(x, y, ptr, length)/ - will add input from keyboard feature. <tt/ptr/ works as in
1509 previous example and points to place where text is to be stored. Note that the contents of this
1510 place will be shown upon creating window. <tt/length/ is the maximum number of characters to input.
1512 <tt/DB_SYSOPV(ptr)/ - this sets <tt/otherPressVec/ to given pointer. It is called on every keypress.
1514 <tt/DB_GRPHSTR(ptr)/ - data for this command is the pointer for <tt/GraphicsString/ commands.
1516 <tt/DB_GETFILES(x, y)/ - for standard window you should pass 4 for both x and y. This function
1517 draws file selection box and searches current drive for files. Before call to <tt/DoDlgBox/ you
1518 must load <tt/r7L/ with GEOS filetype of searched files and <tt/r10/ with class text. In <tt/r5/
1519 you have to load pointer to a <tt/char[17]/ where selected filename will be copied. It works
1520 like <tt/FindFTypes/ but is limited to first 16 files.
1522 <tt/DB_OPVEC(ptr)/ - this sets the new pointer for button press function, if you pass
1523 <tt/RstrFrmDialogue/ here you will cause the window to close after pressing mouse button.
1525 <tt/DB_USRICON(x, y, ptr)/ - places single user icon (click box) on window, <tt/ptr/ points at a
1526 <tt/struct icondef/ but fields <tt/x/ and <tt/y/ are not used here. You can have at most 8 click
1527 boxes in a window, this is internal limit of GEOS Kernal.
1529 <tt/DB_USRROUT(ptr)/ - this command causes to immediately call user routine pointed by <tt/ptr/.
1531 <sect2>GraphicsString command string
1533 <tt/GraphicsString/ is a very powerful routine to initialize whole screen at once. There are
1534 predefined macros for all commands, names are self-explanatory, see them in <tt/ggraph.h/. Last
1535 command have to be <tt/GSTR_END/. There is custom type defined for the command string: <tt/graphicStr/.
1537 Here is an example for clearing the screen:
1539 const graphicStr example = {
1542 RECTANGLETO(319,199)
1546 <sect2>InitRam table
1548 This type of data is used to initialize one or more bytes in many places at once. The format is
1551 void example = {
1552 (unsigned)address_to_store_values_at,
1553 (char)number_of_bytes_that_follow,
1554 (char)data,(char)data (...)
1555 (...) - more such definitions
1556 (unsigned)NULL - address of 0 ends the table