1 <!doctype linuxdoc system>
5 <!-- Title information -->
8 <author>Maciej Witkowiak, <htmlurl url="mailto:ytm@elysium.pl" name="ytm@elysium.pl">
9 <date>v1.2, 26.12.1999, 16.03.2000, 19-22.03.2000, 11,29.07.2000, 3-4,15.07.2001
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 It is safe to use these includes: <tt/dio.h, errno.h, geos.h, joystick.h, mouse.h, stdlib.h,
43 I am an assembler programmer and GEOSLib was designed in such way that cc65 could emit the best
44 available code (well, the best as for machine :). Many of the <tt/void foo (void)/ functions are
45 just raw calls to Kernal (assembled just as <tt/jsr _foo/), look in <tt/gsym.h/, where you
46 will find many definitions of standard GEOS locations. Access to these addresses is optimized by
47 cc65 to simple <tt/lda/ and <tt/sta/. Don't be afraid to use the power of C.
51 You will not need c64 or c128 for development. The only hardware requirement is a PC capable of
52 runing cc65. You will however need c64 or c128 emulator and GEOS image disks (.d64) to test your
57 <item><em/cc65/ Excellent package containing C crosscompiler, crossassembler and linker, you
58 can get it from: <htmlurl url="http://www.von-bassewitz.de/uz/cc65/"
59 name="http://www.von-bassewitz.de/uz/cc65/">
60 <item><em/VICE/ This is portable C64, C128 and few other Commodore computers emulator, you
61 can obtain it from: <htmlurl url="http://www.cs.cmu.edu/~dsladic/vice/vice.html"
62 name="http://www.cs.cmu.edu/~dsladic/vice/vice.html">. VICE package contains
63 c1541 program that is able to convert/unconvert GEOS files to disk images.
64 <item><em/Star Commander/ This tool is only for DOS. You will need it for transferring
65 object files from PC to 1541. There's also one important ability of this
66 tool - it automatically un-converts .cvt files into GEOS native format on
68 <item><em/cbm4linux/ A Linux kernel module that allows for communication with 1541 and
69 other Commodore IEC bus drives. It can be replacement for Star Commander if
70 you want only to transfer files to a disk and uncovert using GEOS program for
71 this purpose. Check out: <htmlurl url="http://www.lb.shuttle.de/puffin/cbm4linux/"
72 name="http://www.lb.shuttle.de/puffin/cbm4linux">
75 VICE and cc65 are portable - they run on variety of platforms - DOS, Win32 and UNIX. GEOSLib only
78 <em/Update:/ starting from v2.5.0 GEOSLib is a part of cc65 package as its GEOS support.
82 I want to thank Uz for his cc65 package, Alexander Boyce for his excellent GEOS Programmer's
83 Reference Guide and BSW for GEOS.
85 GEOSLib is covered by the same license as cc65. You can find the whole text among documentation.
86 I would really appreciate if you would like to send me your comments, suggestions, questions,
87 changes, bug reports etc. I will also appreciate if you will just give me a sign that you are
88 using GEOSLib - not especially something big and important, mail me even if you are just playing
91 You can send postcards with hellos to:
93 Maciej Witkowiak, ul. Slowackiego 6/57, 77-400 ZLOTOW
97 e-mail: <tt/ytm@elysium.pl/
99 <sect>What have you got and what to do with it?
101 This chapter describes some rules you ought to obey, and how to use GEOSLib.
105 Think twice before you use standard C library function. In current implementation almost always
106 you will get better code using only <tt/geos.h/. This will change in next releases as standard
107 functions will become wrappers to native GEOS Kernal.
109 Apart from this file, which merely describes only standard GEOS library functions, you should read
110 <tt/grc/ (GEOS resource compiler) documentation. There are informations about necessary resource
111 files (each GEOS application neeeds at least one) and the building process - what should be done
116 All in all, you just need to place
118 #include <geos.h>
120 on top of your source.
122 Please read cc65's documentation on how to compile C, assembler and link everything together.
124 GEOSLib building process isn't yet defined stable. Detailed information how to link everything
125 together is in separated file together with resource compiler documentation.
127 As a general rule read the sources of example programs and read the headers. These are the most
128 reliable sources of knowledge ;). You will also find there many C macros representing various
129 arguments passed to functions. Please use them. You will find your sources easier to understand,
130 and it will be easier to find bugs.
132 All types used in GEOSLib are <tt/unsigned/.
134 Screen coordinates are given in pixels unless stated differently.
136 <sect1>Notes on style
138 All programs start their execution on <tt/main/ function. Unlike plain C exiting from this function
139 doesn't mean end of program. GEOS is event-driven environment where applications are only executing
140 events, main loop is in kernal. <tt/main/ function should setup the screen, menus etc. and return.
141 Real end of the program should be called from event call, e.g. from menu item. You can force end of
142 program and return to DeskTop either by standard <tt/exit (0)/ function or by <tt/EnterDeskTop()/.
143 Currently they are almost the same (last minute note: don't use <tt/exit/ ever, it's broken right
146 Whenever possible use definitions from <tt/gsym.h/. The resulting code is translated by cc65 into
147 series of <tt/lda/ and <tt/sta/, so you can't do it better :-).
149 Don't hesitate to use library functions. Everything was written with size and speed in mind. In
150 fact many calls are just redirections to GEOS kernal which results in simple <tt/jsr/.
152 You might wonder why I have chosen sometimes weird order of arguments in functions. It is because
153 I wanted to avoid unnecessary pushing and popping arguments from stack. cc65 can pass single <tt/int/
154 through CPU registers.
156 Do not try to compile in strict ANSI mode. I'm using some cc65 extensions which are not available in
159 <sect>Library Functions
161 Functions here are sorted more or less in the way they appear in header files. This way I am able
162 to keep functions covering similar task near each other. All function names are identical to those
163 from <tt/geosSym/ file provided with GeoProgrammer package. Only my extensions to <tt/geosSym/
164 are covered by new names, but I tried to keep them in the naming convention.
168 This section covers drawing package of GEOS along with text output routines.
172 <tt/void SetPattern (char pattern)/
174 This function sets current pattern to given. There are 32 different patterns in GEOS. You can
175 see them together in the filling box in GeoPaint.
177 <sect2>GraphicsString
179 <tt/void GraphicsString (char *myGString)/
181 One of the more powerfull routines of GEOS. This function calls other graphic functions depending
182 on given command string. See structures chapter for more detailed description of the structure of it.
184 <sect2>Rectangle functions
186 Parameters to those functions are grouped in <tt/struct window drawWindow/. To speed up things and
187 reduce overhead this structure is glued to zero page locations, where all rectangle functions
188 expect their parameters. You can modify data directly (e.g. <tt/drawWindow.top=10/) or via
189 <tt/InitDrawWindow/ function. Contents of <tt/drawWindow/ are guaranteed not to change only when
190 using graphics functions. In other case you should keep your data in separate <tt/struct window/
191 and use <tt/InitDrawWindow/ before first call to rectangle functions.
193 <sect3>InitDrawWindow
195 <tt/void InitDrawWindow (struct window *myWindow)/
197 This function only copies contents of <tt/myWindow/ into system area of <tt/drawWindow/. Use it
198 if for some reason you have to keep window data out of zero page space.
202 <tt/void Rectangle (void)/
204 This draws on screen rectangle filled with current pattern.
206 <sect3>FrameRectangle
208 <tt/void FrameRectangle (char pattern)/
210 This one draws frame with given line pattern.
212 <sect3>InvertRectangle
214 <tt/void InvertRectangle (void)/
216 Just as the name says...
218 <sect3>ImprintRectangle and RecoverRectangle
220 <tt/void ImprintRectangle (void)/
222 <tt/void RecoverRectangle (void)/
224 These two functions are for copying parts of the screen to (<tt/Imprint/) and from (<tt/Recover/)
225 backbuffer of the screen. For example when drawing new menu box GEOS first uses
226 <tt/ImprintRectangle/ to save the area under the box, and restores it by <tt/RecoverRectangle/ upon
229 <sect2>Line Functions
231 GEOS drawing package is optimized so there are different functions for drawing vertical and
234 <sect3>HorizontalLine
236 <tt/void HorizontalLine (char pattern, char y, int xStart, int xEnd)/
238 This function draws horizontal line using given pattern - here it is a true bit pattern, not
239 pattern set by <tt/SetPattern/.
243 <tt/void InvertLine (char y, int xStart, int xEnd)/
245 There is only horizontal version.
249 <tt/void RecoverLine (char y, int xStart, int xEnd)/
251 This function recovers only one line. It is utilized by <tt/RecoverRectangle/. See its description
256 <tt/void VerticalLine (char pattern, char yStart, char yEnd, int x)/
258 This function draws vertical line using given pattern. Note that <tt/pattern/ is not a pattern
259 number as set in <tt/SetPattern/ but a true bit pattern.
263 <tt/void DrawLine (struct window *myWindow)/
265 <tt/top/ parameters of <tt/struct window/ describe the starting point of the line, while
266 <tt/bottom/ are for the ending point. Current pattern is used for drawing.
268 <sect2>Point Functions
270 Parameters to these two functions are passed by a pointer to own <tt/struct pixel/ filled with
275 <tt/void DrawPoint (struct pixel *myPixel)/
277 Draws single point on the screen, no matter what the current pattern is.
281 <tt/char TestPoint (struct pixel *myPixel)/
283 This function tests if given pixel is set and returns true or false.
285 <sect2>Character and string output
289 <tt/void PutChar (char character, char y, char x)/
291 This function outputs single character using current style and font to screen.
295 <tt/void PutString (char *myString, char y, int x)/
297 Same as <tt/PutChar/ except the fact that you can output whole <tt/NULL/-terminated string.
298 See <tt/ggraph.h/ for list of tokens that you can also place in the string - like <tt/CBOLDON/ or
303 <tt/void PutDecimal (char parameter, int value, char y, int x)/
305 This function converts <tt/value/ to its decimal representation and outputs it to the screen.
306 Depending on given <tt/parameter/ the string can be filled with zeroes (string always 5 characters
307 long) or not, to be left or right justified to given pixel. See <tt/ggraph.h/ for predefined
308 values for <tt/parameter/.
314 <tt/char GetCharWidth (char character)/
316 This function returns real width (in pixels) of given character with current font. It can be used
317 for counting the length of string on screen, allowing for indentation or justification.
321 <tt/void LoadCharSet (struct fontdesc *myFont)/
323 This function forces GEOS to use given font instead of own. <tt/myFont/ should be casted from
324 pointer to the start of area where was loaded record from font file (VLIR structure).
328 <tt/void UseSystemFont (void)/
330 This function forces GEOS to use built-in BSW font.
332 <sect2>Bitmap handling
334 I'm not quite sure how are these functions working (except <tt/BitmapUp/) so you should
335 probably look into library sources and compare it with your knowledge. Please let me know
336 if something is wrong or broken.
340 <tt/void BitmapUp (struct iconpic *myPic)/
342 This function unpacks the bitmap and places it on the screen - just as you set it in the
343 <tt/struct iconpic/ pointer to which you pass. See <tt/gstruct.h/ for description of this
344 structure. Note that you can only use packed GEOS bitmaps - simple Photo Scrap is in this format.
348 <tt/void BitmapClip (char skipLeft, char skipRight, int skipTop, struct iconpic *myPic)/
350 This function acts similar to <tt/BitmapUp/ but you can also define which parts of the bitmap are
351 to be drawn - you give the number of columns (8-pixel) to skip on the right and left of the bitmap,
352 and the number of rows to skip from the top if it.
356 <tt/void BitOtherClip (void *proc1, void *proc2, char skipLeft, char skip Right, int skipTop,
357 struct iconpic *myPic)/
359 Similar to the previous one with some extension. <tt/proc1/ is called before reading a byte (it
360 returns in .A next value), and <tt/proc2/ is called every time the parser reads a byte which is
361 not a piece of pattern (byte of code greater than 219). Both procedures should be written
362 separately in assembler and declared as <tt/__fastcall__/ returning char.
364 <sect1>Menus and Icons
366 Here you will find information about functions related with menus and icons.
370 Menus are essencial for GUI. GEOS can handle only one menu at a time, but each menu can call
371 another one, which results in submenu tree. There can be up to 8 menu levels, each one with up
374 Menus are initialized with <tt/DoMenu/ and then Kernal takes care for everything. Your code
375 (called from event handler) should be a function without parameters, returning void. You should
376 use <tt/DoPreviousMenu/ or <tt/GotoFirstMenu/ at least once in its code to have the screen clean.
380 <tt/void DoMenu (struct menu *myMenu)/
382 This function initializes GEOS menu processor and exits. See <tt/DoMenu structure/ for more
383 information about it. Know that many GEOS application just initializes the screen, menu and
384 exits to main Kernal loop, this proves the power of <tt/DoMenu/.
388 <tt/void ReDoMenu (void)/
390 This simply redraws the menu at lowest level. It works like calling <tt/DoMenu/ again with
395 <tt/void RecoverMenu (void)/
397 This function erases current menu from the screen. It doesn't change the menu level.
399 <sect3>RecoverAllMenus
401 <tt/void RecoverAllMenus (void)/
403 This calls <tt/RecoverMenu/ and erases all menus from the screen. Then the menu level is
406 <sect3>DoPreviousMenu
408 <tt/void DoPreviousMenu (void)/
410 This functions causes menu processor to go back one menu level. You should use it in menu
411 handler code to have the screen clean.
415 <tt/void GotoFirstMenu (void)/
417 This one jumps back to the topmost menu. If there is only menu and submenu it works the
418 same as <tt/DoPreviousMenu/.
422 Icons are working similar to menus except the fact that there is only one level. Icons are
423 defined as a screen area filled with a bitmap, but if you would setup icons and erase the
424 screen they are still active and clicking in the place where formerly an icon was will cause
425 an effect. Similary if you would setup icons and then turn them off with <tt/ClearMouseMode/
426 the bitmap will be still on the screen but clicking on it would not cause any action.
427 There is only one, but powerful icon function.
431 <tt/void DoIcons (struct icontab *myIconTab)/
433 This function initializes all icons that are present on the screen at once. For more information
434 look at <tt/Icons/ chapter in this manual.
438 This chapter covers the most powerful GEOS user interface function - <tt/DoDlgBox/.
444 <tt/char DoDlgBox (char *dialogString)/
446 DialogBox returns one byte. It can be the value of one of six standard icons (see <tt/gdlgbox.h/)
447 or whatever closing routine passes. Register <tt/r0L/ also contains this value.
449 Read structures chapter for the specs of the <tt/dialogString/.
451 <sect3>RstrFrmDialogue
453 <tt/char RstrFrmDialogue/
455 This function called from within DialogBox event immediately closes the DialogBox and returns
456 the owner ID (or whatever caller has in the .A register).
458 <sect2>GEOSLib extensions
460 To simplify usage of DoDlgBox from C I've wrote some help functions - wrappers for DoDlgBox,
461 with predefined data. In one word - these are standard DialogBoxes you can see in almost every
464 <sect3>DlgBoxYesNo, DlgBoxOkCancel, DlgBoxOk
466 <tt/char DlgBoxYesNo (char *line1, char *line2)/
468 <tt/char DlgBoxOkCancel (char *line1, char *line2)/
470 <tt/void DlgBoxOk (char *line1, char *line2)/
472 These function show two lines of text in standard-sized DialogBox. You can read the code of
473 pressed icon from return value. E.g. for <tt/DlgBoxYesNo/ it can only be <tt/YES/ or <tt/NO/.
475 <sect3>DlgBoxGetString
477 <tt/char DlgBoxGetString (char *string, char strlen, char *line1, char *line2)/
479 This function prompts user for entering a string of at most <tt/strlen/ characters. It is returned
480 in <tt/string/. The two given lines of text are shown above the input line. Please remember
481 that there is also <tt/CANCEL/ icon in the DialogBox and you should test if user confirmed his
482 input or gave up. The <tt/string/ is also shown so you can place default input there or remember
483 to place <tt/NULL/ at start.
485 <sect3>DlgBoxFileSelect
487 <tt/char DlgBoxFileSelect (char *class, char filetype, char *filename)/
489 This routine is the standard file selector. It can return <tt/OPEN/, <tt/CANCEL/ or disk error
490 on reading the directory or opening the disk.
491 There is also <tt/DISK/ icon shown, but it is handled internally. You pass as input parameters
492 <tt/filetype/ and pointer to string containing the first part of file's class. If this string is
493 empty (<tt/NULL/ at the start), then all files with given filetype will be shown.
495 At present this file selector handles only first 16 files of given type and supports only one
498 <sect1>Mouse, Sprites and Cursors
500 You will find here functions related to sprite and mouse drawing and handling.
502 <sect2>Mouse related functions
504 These cover mouse - as a general pointing device, but expect user to utilize as different devices
505 as digital or analog joystick, mouse, lightpen or koalapad (whatever it is).
507 <sect3>StartMouseMode
509 <tt/void StartMouseMode (void)/
511 This function initializes mouse vectors - <tt/mouseVector/ and <tt/mouseFaultVec/, and then
514 <sect3>ClearMouseMode
516 <tt/void ClearMouseMode (void)/
518 This function disables all mouse actitivies - icons and menus stop to respond to mouse events,
519 but they are not cleared from the screen.
521 <sect3>MouseUp and MouseOff
523 <tt/void MouseUp (void)/
525 <tt/void MouseOff (void)/
527 The first function turns the mouse pointer on. It will appear on next IRQ. The second one does
528 the opposite - it turns off the pointer, but its position is still updated by input driver.
532 <tt/char IsMseInRegion (struct window *myWindow)/
534 This function tests if mouse pointer is actually in given range of screen. See <tt/gsprite.h/ for
535 description of bits in return values - they describe the position in detail.
539 You are free to use any of the eight sprites, but keep in mind that sprite 0 is actually the mouse
540 pointer and sprite 1 can be overwritten when using text prompt.
544 <tt/void DrawSprite (char sprite, char *mySprite)/
546 This function initializes the sprite data. <tt/mySprite/ is a 63-byte table with bitmap data, which
547 is copied to system sprite area (at <tt/sprpic/ - see <tt/gsym.h/). Hardware sprite registers are
548 not initialized and sprite is not yet visible.
552 <tt/void PosSprite (char sprite, struct pixel *myPixel)/
554 This function positions the sprite on the screen. Given coordinates are screen ones - they are
555 converted to sprite coordinates by GEOS. Due to this you cannot use this function to position your
556 sprite off the left or top to the screen.
558 <sect3>EnablSprite and DisablSprite
560 <tt/void EnablSprite (char sprite)/
562 <tt/void DisablSprite (char sprite)/
564 These two functions are responsible for making the sprite visible or not.
566 <sect2>Cursors and Console
568 <sect3>InitTextPrompt
570 <tt/void InitTextPrompt (char height)/
572 This function initializes sprite 1 for text prompt with given <tt/height/. This parameter can be in
575 <sect3>PromptOn and PromptOff
577 <tt/void PromptOn (struct pixel *myPixel)/
579 <tt/void PromptOff (void)/
581 The first function places text prompt in given place and enables its blinking
582 The second one is pretty self-explanatory.
586 <tt/char GetNextChar (void)/
588 This function gets next character from the keyboard queue. If the queue is empty it returns
589 <tt/NULL/, otherwise you receive true ASCII code of a character or value of special (function)
590 key. See <tt/gsprite.h/ for list of them.
594 This chapter covers slightly low-level disk routines. You should use them with care, because
595 you may easily corrupt data on disks. Also remember that contemporary GEOS supports many various
596 devices and sticking to 1541 track layout (e.g. expecting the directory on track 18) might be
599 For some purposes you might consider using <tt/dio.h/ interface to disk access. It is native.
601 All GEOS disk functions return error code in X register. In some cases this is returned by
602 GEOSLib function (if its type is <tt/char/), but in all cases last error is saved in <tt/__oserror/
603 location. If it is nonzero - an error occured. See <tt/gdisk.h/ for the list of possible errorcodes.
604 You need to include <tt/errno.h/ to get <tt/__oserror/, together with standard <tt/errno/. The
605 latter gives less verbose, but still usable information and can be used with <tt/strerror/.
607 For passing parameters use almost always pointer to your data e.g. <tt/ReadBuff (&myTrSe)/.
609 <sect2>Buffer functions
611 These functions are taking single data sector (256 bytes) to read or write on a disk.
613 <sect3>ReadBuff and Writebuff
615 <tt/char ReadBuff (struct tr_se *myTrSe)/
617 <tt/char WriteBuff (struct tr_se *myTrSe)/
619 These functions are reading and writting sector placed at <tt/diskBlkBuf/.
621 <sect3>GetBlock and ReadBlock
623 <tt/char GetBlock (struct tr_se *myTrSe, char *buffer)/
625 <tt/char ReadBlock (struct tr_se *myTrSe, char *buffer)/
627 These two functions are reading a single block directly at 256 byte array placed at <tt/buffer/.
628 The difference between them is that <tt/GetBlock/ will initialize TurboDos in drive if it was not
629 enabled. <tt/ReadBlock/ assumes that it is already enabled thus being slightly faster.
631 <sect3>PutBlock, WriteBlock, VerWriteBlock
633 <tt/char PutBlock (struct tr_se *myTrSe, char *buffer)/
635 <tt/char WriteBlock (struct tr_se *myTrSe, char *buffer)/
637 <tt/char VerWriteBlock (struct tr_se *myTrSe, char *buffer)/
639 Similar to previous but needed for writting the disk. <tt/VerWriteBlock/ verifies the data after
640 writting. In case of error five tries are attempted before error code is returned.
642 <sect2>Directory header
644 Functions described here are operating on <tt/curDirHeader/ where current disk header is stored.
645 On larger capacity drives (than 1541) the second part of directory header in <tt/dir2Head/.
649 <tt/void GetPtrCurDkNm (char *diskName)/
651 This function fills given character string with the name of current disk. It is converted to C
652 standard - string is terminated with <tt/NULL/ character instead of code 160 as in Commodore DOS.
653 Note that passed pointer must point to an array of at least 17 bytes.
655 <sect3>GetDirHead and PutDirHead
657 <tt/char GetDirHead (void)/
659 <tt/char PutDirHead (void)/
661 These functions are reading and writting the directory header. You should use <tt/GetDirHead/ before
662 using any functions described below, and you should use <tt/PutDirHead/ to save the changes on the
663 disk. Otherwise they will be lost. Operating area is the <tt/curDirHead/.
667 <tt/int CalcBlksFree (void)/
669 This function returns the number of free blocks on current disk. It is counted using data in
670 <tt/curDirHead/ so you must initialize the disk before calling it.
674 <tt/char ChkDskGEOS (void)/
676 This functions checks <tt/curDirHead/ for GEOS Format identifier. It returns either true or false,
677 and also sets <tt/isGEOS/ properly. You must initialize the disk before using this.
681 <tt/char SetGEOSDisk (void)/
683 This function initializes disk for use with GEOS. It sets indicator in directory header and
684 allocates a sector for the directory of border files. You don't need to initialize the disk before
689 <tt/char FindBAMBit (struct tr_se *myTrSe)/
691 This function returns the bit value from BAM (Block Allocation Map) for given sector. The bit is
692 set if the sector is free to use. Returned value is always zero if the sector is already allocated.
693 In fact, this function could be used in a following way:
695 #define BlockInUse FindBAMBit
697 if (!SectInUse(&myTrSe)) {
698 ... block not allocated ...
702 Anyway, I feel that this function is too low-level.
704 <sect3>BlkAlloc and NxtBlkAlloc
706 <tt/char BlkAlloc (struct tr_se output[&rsqb, int length)/
708 <tt/char NxtBlkAlloc (struct tr_se *myTrSe, struct tr_se output[&rsqb, int length)/
710 Both functions are allocating enough disk sectors to fit the number of <tt/length/ in them. You
711 will find output in <tt/output/ which is table of <tt/struct tr_se/. The last entry will have the
712 number of track equal to 0 and sector equal to 255. The simpliest way of using them is to use
713 predefined space in GEOS data space and pass <tt/fileTrScTab/, which is a predefined table.
715 The difference between those two is that <tt/NextBlkAlloc/ will start allocating from given sector,
716 and <tt/BlkAlloc/ starts from the first nonused sector.
718 You need to use <tt/PutDirHead/ later to save any changes in BAM.
722 <tt/char FreeBlock (struct tr_se *myTrSe)/
724 Simply deallocates a block in BAM. You need to update BAM with <tt/PutDirHead/.
728 <tt/struct tr_se SetNextFree (struct tr_se *myTrSe)/
730 This function finds the first free sector starting from given track and sector and allocates it.
731 It might return the same argument if the given block is not allocated. I wanted it to be type
732 clean, but it made usage a bit tricky. To assign a value to own <tt/struct tr_se/ you have to
733 cast both variables to <tt/int/. E.g.
737 (int)myTrSe=(int)SetNextFree(&otherTrSe);
740 In this example <tt/otherTrSe/ can be replaced by <tt/myTrSe/.
742 NOTE that you <em/must/ use casting to have correct values.
744 <sect2>Low-level disk IO
746 Functions described here are more usable in kernal or drivers code, less common in applications,
747 but who knows, maybe someone will need them.
749 <sect3>EnterTurbo, ExitTurbo, PurgeTurbo
751 <tt/void EnterTurbo (void)/
753 <tt/void ExitTurbo (void)/
755 <tt/void PurgeTurbo (void)/
757 These functions are interface to GEOS TurboDos feature which makes slow Commodore drives a bit
758 more usable. <tt/EnterTurbo/ enables TurboDos unless it is already enabled. If not, then you will
759 have to wait a bit to transfer TurboDos code into disk drive RAM. <tt/ExitTurbo/ disables TurboDos.
760 This is useful for sending some DOS commands for drive e.g. for formatting. Note that before any
761 interaction with Kernal in ROM you have to call <tt/InitForIO/. You don't have to worry about speed.
762 <tt/EnterTurbo/ will only enable TurboDos (no code transfer) if TurboDos was disabled with
763 <tt/ExitTurbo/. <tt/PurgeTurbo/ acts different from <tt/ExitTurbo/ - it not only disables TurboDos,
764 but also removes it from drive RAM (not quite true, but it works like that). After using
765 <tt/PurgeTurbo/ the next call to <tt/EnterTurbo/ will reload drive RAM.
767 <sect3>ChangeDiskDevice
769 <tt/char ChangeDiskDevice (char newDevice)/
771 This function changes logical number of current device (in fact drives only) with given one. It is
772 usable for swapping drives. There's no check if given <tt/newDevice/ already exist, so if you want
773 to change the logical number of drive 8 to 9 and you have drive number 9 then GEOS will probably
774 hang on disk access. Use safe, large numbers. Note that safe IEC range is 8-31.
776 <sect2>Disk Initialization
778 GEOS has two functions for initialization ('logging' as they say on CP\M) the disk.
781 <tt/char OpenDisk (void)/
783 This function initializes everything for a new disk. It loads and enables TurboDos if needed.
784 Then the disk is initialized with <tt/NewDisk/. Next, <tt/GetDirHead/ initializes <tt/curDirHead/.
785 Disk names are compared and if they differ then disk cache on REU is cleared. Finally format is
786 checked with <tt/ChkDkGEOS/ and disk name is updated in internal tables.
790 <tt/char NewDisk (void)/
792 This function is similar to DOS command I. It clears REU cache and enables TurboDos if needed.
796 This section cover GEOS file interface.
798 <sect2>Directory handling
800 Functions described here are common for SEQ and VLIR structures.
802 <sect3>Get1stDirEntry and GetNxtDirEntry
804 <tt/struct filehandle *Get1stDirEntry (void)/
806 <tt/struct filehandle *GetNxtDirEntry (void)/
808 These two functions are best suited for scanning whole directory for particular files. Note that
809 returned filehandles describes all file slots in the directory - even those with deleted files.
810 The return value can be obtained by casting both sides to <tt/int/ - as in <tt/SetNextFree/
811 function or read directly after call to those two functions from <tt/r5/. Current sector number
812 is in <tt/r1/ and sector data itself is in <tt/diskBlkBuf/.
816 <tt/char FindFile (char *fName)/
818 This function scans whole directory for the given filename. It returns either 0 (success) or 5
819 (FILE_NOT_FOUND, defined in <tt/gdisk.h/) or any other fatal disk read error. After successful
820 <tt/FindFile/ you will have <tt/struct filehandle/ at <tt/dirEntryBuf/ filled with file's data and
821 other registers set as described in <tt/GetNxtDirEntry/.
825 <tt/char FindFTypes (char *buffer, char fType, char fMaxNum, char *classTxt)/
827 This function scans directory and fills a table at <tt/buffer/ with <tt/char [17]/ entries.
828 <tt/fType/ is GEOS type of searched files and <tt/classTxt/ is a string for Class field in file
829 header. Class will match if given will be equal or shorter than that found in file's header block.
830 If you want just to find all files with given GEOS type you should pass empty string or <tt/NULL/ as
831 <tt/classTxt/. Be warned that for searching <tt/NON_GEOS/ files must pass <tt/NULL/ as <tt/classTxt/.
832 <tt/fMaxNum/ is the maximal number of found files, thus the <tt/buffer/ must
833 provide area of size equal to <tt/17 * fMaxNum/.
834 This function returns the number of found files, ranging from 0 to number passed as <tt/fMaxNum/.
835 Return value can be also restored from <tt/r7H/.
839 <tt/char DeleteFile (char *fName)/
841 This function deletes a file by its name. It works for SEQ and VLIR files.
845 <tt/char RenameFile (char *oldName, char *newName)/
847 I think it is obvious...
851 <tt/char GetFHdrInfo (struct filehandle *myFile)/
853 This function loads the file header into <tt/fileHeader/ buffer. Using after e.g. <tt/FindFile/
854 you can pass address of <tt/dirEntryBuf/.
856 <sect2>Common and SEQ structure
858 Functions described here are common for SEQ and VLIR structures because arguments passed are
859 starting track and sector which may point either to start of a chain for VLIR or data for SEQ.
863 <tt/char ReadFile (struct tr_se *myTrSe, char *buffer, int fLength)/
865 This function reads at most <tt/fLength/ bytes into <tt/buffer/ from chained sectors starting at
870 <tt/char ReadByte (void)/
872 This function returns next byte from a file. Before the first call to it you must load <tt/r5/
873 with <tt/NULL/, <tt/r4/ with sector buffer address and <tt/r1/ with track and sector of the
874 first block of a file.
875 Remember to not modify <tt/r1/, <tt/r4/ and <tt/r5/. These registers must be preserved between
876 calls to <tt/ReadByte/.
878 Returned value is valid only if there was no error. End of file is marked as <tt/BFR_OVERFLOW/
879 in <tt/__oserror/, this is set when trying to read one byte after the end of file, in this case
880 returned value is invalid.
884 <tt/char SaveFile (struct fileheader *myHeader)/
886 <tt/SaveFile/ will take care of everything needed to create a GEOS file, no matter VLIR of SEQ
887 structure. All you need to do is to place data in proper place and prepare a header which will
888 contain all information about a file.
890 You have to declare a <tt/struct fileheader/ and fill it with proper values. There is only one
891 difference - the first two bytes which are link to nonexistant next sector are replaced by a
892 pointer to the DOS filename of the file.
894 When saving files two most important fields in <tt/struct fileheader/ are <tt/fileheader.load_address/
895 and <tt/fileheader.end_address/.
899 <tt/char FreeFile (struct tr_se myTable[])/
901 This function deallocates all sectors contained in passed table.
905 <tt/char FollowChain(struct tr_se *myTrSe, char *buffer)/
907 This function fills a <tt/struct tr_se/ table at <tt/buffer/ with sector numbers for chain of
908 sectors starting with <tt/myTrSe/. You can pass such data (<tt/buffer/) to e.g. <tt/FreeFile/.
910 <sect2>VLIR structure
912 Here are informations about VLIR files (called later as RecordFile) and functions.
914 VLIR is a file which consists of up to 127 SEQ-like files called records. Each record is like one
915 SEQ structure file. Records are grouped together, described by common name - VLIR file name and
916 own number. Each record pointed by its number is described by starting track and sector numbers.
917 VLIR structures allow records to be empty (<tt/tr_se/ of such record is equal to <tt/{NULL,$ff}/),
918 or even non-exist (<tt/{NULL,NULL}/). Any other numbers represent starting track and sector of
921 In GEOS there can be only one file opened at a time. Upon opening VLIR file some information
922 about it are copied into memory. You can retrieve records table at <tt/fileTrScTab/ (table of
923 128 <tt/struct tr_se/) and from <tt/VLIRInfo/ (<tt/struct VLIR_info/.
924 E.g. size of whole VLIR file can be retrieved by reading <tt/VLIRInfo.fileSize/.
926 <sect3>OpenRecordFile
928 <tt/char OpenRecordFile (char *fName)/
930 This function finds and opens given file. An error is returned if file is not found or it is not
931 in VLIR format. Information in <tt/VLIRInfo/ is initialized. VLIR track and sector table is
932 loaded at <tt/fileTrScTab/ and will be valid until call to <tt/CloseRecordFile/ so don't modify it.
933 You should <tt/PointRecord/ before trying to do something with file.
935 <sect3>CloseRecordFile
937 <tt/char CloseRecordFile (void)/
939 This function calls <tt/UpdateRecordFile/ and clears internal GEOS variables.
941 <sect3>UpdateRecordFile
943 <tt/char UpdateRecordFile (void)/
945 This function fill check <tt/VLIRInfo.fileWritten/ flag and if it is set, then <tt/curDirHead/ will
946 be updated along with size and date stamps in directory entry.
950 <tt/char PointRecord (char recordNumber)/
952 This function will setup internal variables (and <tt/VLIRInfo.curRecord/) and return the track and
953 sector of given record in <tt/r1/. Note that the data may not be valid (if record is non-existing
954 you will get 0,0 and if it is empty - 255, 0).
956 <sect3>NextRecord and PreviousRecord
958 <tt/char NextRecord (void)/
960 <tt/char PreviousRecord (void)/
962 These two work like <tt/PointRecord/. Names are self-explanatory.
966 <tt/char AppendRecord (void)/
968 This function will append an empty record ( pair of 255,0 ) to current VLIR track and sector
969 table. It will also set <tt/VLIRInfo.curRecord/ to its number.
973 <tt/char DeleteRecord (void)/
975 This function will remove current record from the table, and move all current+1 records one place
976 back (in the table). Note that there's no BAM update and you must call <tt/UpdateRecordFile/ to
981 <tt/char InsertRecord (void)/
983 This function will insert an empty record in place of <tt/VLIRInfo.curRecord/ and move all following
984 records in table one place forward (contents of <tt/VLIRInfo.curRecord/ after call to <tt/InsertRecord/
985 can be found in <tt/VLIRInfo.curRecord + 1/).
987 <sect3>ReadRecord and WriteRecord
989 <tt/char ReadRecord (char *buffer, int fLength)/
991 <tt/char WriteRecord (char *buffer, int fLength)/
993 This function will load or save at most <tt/fLength/ bytes from currently pointed record into or from
996 <sect1>Memory and Strings
998 Functions covered in this section are common for whole C world - copying memory parts and
999 strings is one of the main computer tasks. GEOS also has interface to do this. These functions
1000 are replacement for those like <tt/memset, memcpy, strcpy/ etc. from standard libraries.
1002 However some of them have slighty different calling convention (order of arguments to be specific),
1003 so please check their syntax here before direct replacing.
1005 Please note that the memory described as <em/strings/ are up to 255 characters (without
1006 counting the terminating <tt/NULL/), and <em/regions/ cover whole 64K of memory.
1010 <tt/void CopyString (char *dest, char *src)/
1012 This function copies string from <tt/src/ to <tt/dest/, until it reaches <tt/NULL/. <tt/NULL/
1017 <tt/char CmpString (char *s1, char *s2)/
1019 This function compares string <tt/s1/ to <tt/s2/ for equality - this is case sensitive, and both
1020 strings have to have the same length. It returns either <tt/true/ or <tt/false/.
1022 <sect2>CopyFString and CmpFString
1024 <tt/void CopyFString (char length, char *dest, char *src)/
1026 <tt/char CmpFString (char length, char *s1, char *s2)/
1028 These two are similar to <tt/CopyString/ and <tt/CmpString/ except the fact, that you provide
1029 the length of copied or compared strings. The strings can also contain several <tt/NULL/
1030 characters - they are not treated as delimiters.
1034 <tt/int CRC (char *src, int length)/
1036 This function calculates the CRC checksum for given memory range. I don't know if it is
1037 compatible with standard CRC routines.
1039 <sect2>FillRam and ClearRam
1041 <tt/void FillRam (char *dest, char value, int length)/
1043 <tt/void ClearRam (char *dest, int length)/
1045 Both functions are filling given memory range. <tt/ClearRam/ fills with <tt/NULLs/, while
1046 <tt/FillRam/ uses given <tt/value/. Be warned that these functions destroy <tt/r0, r1 and
1047 r2L/ registers. <tt/FillRam/ is an alias for <tt/memset/.
1051 <tt/void MoveData (char *dest, char *src, int length)/
1053 This functions copies one memory region to another. There are checks for overlap and the
1054 non-destructive method is chosen. Be warned that this function destroys contents of
1055 <tt/r0, r1 and r2/ registers. This is also alias for <tt/memcpy/
1059 <tt/void InitRam (char *table)/
1061 This function allows to initialize multiple memory locations with single bytes or strings.
1062 This is done with <tt/table/ where everything is defined. See structures chapter for description of
1063 <tt/InitRam's/ command string.
1065 <sect2>Stash, Fetch, Swap, and VerifyRAM
1067 <tt/void StashRAM (char bank, int length, char *reuAddress, char *cpuAddress)/
1069 <tt/void FetchRAM (char bank, int length, char *reuAddress, char *cpuAddress)/
1071 <tt/void SwapRAM (char bank, int length, char *reuAddress, char *cpuAddress)/
1073 <tt/ char VerifyRAM (char bank, int length, char *reuAddress, char *cpuAddress)/
1075 These functions are interface to REU - Ram Expansion Unit. I think that they are self-explanatory.
1076 You can check for REU presence by taking value of <tt/ramExpSize/.
1078 <sect1>Processes and Multitasking
1080 Weird? Not at all. GEOS has limited multitasking ability. You can set up a chain of functions
1081 called in specified intervals and you can put the main program to sleep without disturbing other
1082 tasks and making user interface unresponsive.
1084 <sect2>InitProcesses
1086 <tt/void InitProcesses (char number, struct process *processTab)/
1088 This is the main initialization routine. After calling it processes are set up, but not
1089 enabled. The parameters for <tt/InitProcesses/ are:
1091 <item><tt/number/ - number of processes
1092 <item><tt/processTab/ - table of <tt/struct process/, with size equal to <tt/number/
1095 Single task is described by entry in <tt/processTab/, it contains two values - <tt/pointer/ to
1096 task function and number of <tt/jiffies/ which describe the delay between calls to task. On PAL
1097 systems there are 50 jiffies per second, while on NTSC there are 60.
1099 The maximum number of tasks is 20. Be warned that GEOS doesn't check if parameters are valid and
1100 if <tt/processTab/ would be too large it would overwrite existing data in GEOS space.
1102 There's one important thing - the last entry in <tt/processTab/ has to be <tt/NULL,NULL/, so the
1103 maximum size of <tt/processTab/ is equal to 21.
1105 See description of <tt/process/ structure for more detailed discussion on this.
1107 <sect2>RestartProcess and EnableProcess
1109 <tt/void RestartProcess (char processNumber)/
1111 <tt/void EnableProcess (char processNumber)/
1113 These two functions start the task counter. <tt/RestartProcess/ for each process should be called
1114 after <tt/InitProcesses/, because it resets all flags and counters and it starts the counters.
1116 <tt/RestartProcess/ enables counters and sets their initial value to that given in <tt/processTab/.
1118 <tt/EnableProcess/ forces given process to execute by simulating the timer running out of time.
1120 <sect2>BlockProcess and UnBlockProcess
1122 <tt/void BlockProcess (char processNumber)/
1124 <tt/void UnBlockProcess (char processNumber)/
1126 <tt/BlockProcess/ disables the execution of given process, but this does not disable the timers.
1128 <tt/UnBlockProcess/ does the opposite.
1130 <sect2>FreezeProcess and UnFreezeProcess
1132 <tt/void FreezeProcess (char processNumber)/
1134 <tt/void UnFreezeProcess (char processNumber)/
1136 <tt/FreezeProcess/ disables timer for given process. <tt/UnFreezeProcess/ does the opposite.
1137 This is not equal to <tt/RestartProcess/ as timers are not filled with initial value.
1141 <tt/void Sleep (int jiffies)/
1143 This function is multitasking sleep - the program is halted, but it doesn't block other functions.
1144 The only argument here is the number of jiffies to wait until app will wake up.
1146 You can force to sleep not only the main application routine, but also processes-tasks. Be warned
1147 that the maximum number of sleeping functions is 20. If it would be larger it will overwrite
1148 parameters of already sleeping functions in GEOS kernal data space, leading to crash.
1154 <tt/void FirstInit (void)/
1156 This function initializes some GEOS variables and mouse parameters. This is called on GEOS boot
1157 up. You shouldn't use this unless you know what you are doing.
1159 <sect2>InitForIO and DoneWithIO
1161 <tt/void InitForIO (void)/
1163 <tt/void DoneWithIO (void)/
1165 These functions are called by some disk routines. You should call them only if you want to
1166 do something with IO registers or call one of Kernal's routines.
1170 <tt/void MainLoop (void)/
1172 Your programs exits to MainLoop upon exiting from <tt/main/, but you might need this function in
1173 menu and icon code. When in <tt/MainLoop/ systems waits for your action - using icons, keyboard
1174 or menus to force some specific action from program.
1178 <tt/void EnterDeskTop (void)/
1180 This is default exit code of your application. It is finish of <tt/exit()/, but you may need it
1181 in other places of application.
1185 <tt/void ToBASIC (void)/
1187 This one is another way of finishing application - forcing GEOS to shutdown and exit to BASIC.
1188 I was considering whether to include it or not, but maybe someone will need it. Which is I doubt.
1192 <tt/void Panic (void)/
1194 This calls system's <tt/Panic/ handler - it shows dialog box with message
1196 System error at:xxxx
1198 where <tt/xxxx/ is last known execution address (caller). By default this is bound to <tt/BRK/
1199 instruction, but it might be usable in debugging as kind of <tt/assert/.
1201 System is halted after call to <tt/Panic/.
1205 <tt/void CallRoutine (void *myFunct)/
1207 This is system caller routine. You need to provide pointer to a function and it will be immediately
1208 called, unless the pointer is equal to <tt/NULL/. This is the main functionality of this function -
1209 you need not to worry if the pointer is valid.
1211 <sect2>GetSerialNumber
1213 <tt/int GetSerialNumber (void)/
1215 This function returns the serial number of system. It might be used for copy-protection, but you
1216 shouldn't do this. Please remember that the Free Software is a true power.
1220 <tt/char GetRandom (void)/
1222 This function returns a random number. It can be also read from <tt/random/ e.g.
1226 but by calling this function you are sure that the results will be always different.
1227 <tt/random/ is updated once a frame (50Hz PAL) and on every call to <tt/GetRandom/
1231 <tt/void SetDevice (char device)/
1233 This function sets current device to given. It might be used together with <tt/InitForIO/,
1234 <tt/DoneWithIO/ and some Kernal routines. Unless new device is a disk drive this only sets
1235 new value in <tt/curDevice/, in other case new disk driver is loaded from REU or internal RAM.
1237 <sect>Library Structures
1239 To simplify usage and optimize passing parameters to functions I have declared several structures
1240 which describe most common objects. Some of these structures are bound to static addresses in
1241 GEOS data space ($8000-$8fff), so you can use their fields directly in optimized way.
1242 Please see <tt/gsym.h/ and find them. All structures are defined in <tt/gstruct.h/ and you may
1243 find also some comments there.
1249 One simple structure describing a point on the screen.
1253 This structure describes a font in one pointsize. There is current font - <tt/struct fontdesc/
1254 bound to <tt/curFontDesc/. You can also force GEOS to use your own fonts by calling
1255 <tt/LoadCharSet/. You just need to open a VLIR font file and load one record - one pointsize
1256 somewhere. At the start of this area you already have all data for <tt/fontdesc/ so you can
1257 pass a pointer to the load adress of that pointsize to <tt/LoadCharSet/.
1261 This widely used structure holds description of a region of the screen. It describes top-left and
1262 bottom-right corners of a window.
1266 Maybe the name isn't the best - it has nothing with <tt/DoIcons/ but with bitmap functions -
1267 <tt/BitmapUp/ for example. This structure holds parameters needed to properly decode and show
1268 a bitmap on the screen. Bitmap has to be encoded - if you have some non-GEOS bitmaps simply
1269 convert them to Photo Scraps - this is the format used by all GEOS bitmap functions - <tt/DoIcons/
1274 These structures describe click boxes (icons) that can be placed on screen or in a dialog box.
1278 This is the definition of a single click box. Please see <tt/gstruct.h/ for description of its fields.
1282 This is toplevel description of icons to be placed and enabled on the screen. This structure
1283 has following fields:
1285 <item><tt/char number/ - total number of icons declared here
1286 <item><tt/struct pixel mousepos/ - after finishing <tt/DoIcons/ mouse pointer will be placed in
1287 this point allowing you to have hint for user what is default action
1288 <item><tt/struct icondef tab[&rsqb/ - this table of size equal to <tt/icontab.number/ contains
1289 descriptions for all icons
1292 <sect1>File and Disk
1296 This simple structure holds track and sector number of something. Do not expect the track to be
1297 in range 1-35, as GEOS can support many various and weird devices. For example my C128 256K
1298 expansion is utilized as RAMDisk with layout of 4 tracks 128 sectors each. However assuming that
1299 track number equal to 0 is illegal might be wise.
1303 This is placeholder for file datestamp. This structure is also present in <tt/struct filehandle/.
1304 GEOS is not Y2K compliant, so if current file has in <tt/filehandle.date.year/ value less than 86
1305 you can safely assume that it is e.g. 2004 and not 1904.
1309 This is main file descriptor. It is either entry in the directory (returned from file functions)
1310 or its copy in <tt/dirEntryBuf/. This is optimized so you can safely get to the file's year e.g.
1311 by testing <tt/dirEntryBuf.date.year/ - it will be compiled to simple <tt/LDA, STA/.
1315 This structure holds fileheader description. You can load file's header into <tt/fileHeader/
1316 fixed area using <tt/GetFHdrInfo/. (note that <tt/fileHeader/ is a place in memory while
1317 <tt/fileheader/ is a structure).
1318 You will also need own fileheader for <tt/SaveFile/.
1324 This structure is defined only for <tt/system_date/. It is slightly different from <tt/f_date/
1325 so I prepared this one. You can e.g. get or set current time using <tt/system_date.s_hour/ and
1326 <tt/system_date.s_minute/. Accesses to these will be optimized to simple <tt/LDA/ and <tt/STA/
1331 You should declare a table of that type to prepare data for <tt/InitProcesses/. The maximum number
1332 of processes is 20, and the last entry has to be equal to <tt/{NULL,NULL}/, so this table may hold
1333 only 21 entries. The first member of this structure (<tt/pointer/) holds the pointer to called
1334 function (void returning void), you will probably have to cast that pointer into int. The second
1335 field <tt/jiffies/ holds the amount of time between calls to that function. On PAL systems there
1336 are 50 jiffies per second, while NTSC have 60 of them.
1338 <sect1>Few thing in detail...
1340 GEOSLib uses cc65 non-ANSI extensions to easily initialize data in memory. This is done with a
1341 kind of array of unspecified length and unspecified type. Here is how it goes:
1343 void example = {
1344 (char)3, (unsigned)3, (char)0 };
1346 Which will be compiled to following string of bytes:
1353 As you see this way it is possible to define data of any type in any order. You must remember to
1354 cast each member to proper type.
1356 <sect2>DoMenu structure
1358 <tt/DoMenu/ is responsible for everything concerned with menu processing. Many, many GEOS programs
1359 are just initializing screen and menu and exit to <tt/MainLoop/. In GEOSLib it is the same as
1360 returning from <tt/main/ function without using <tt/exit(0)/.
1362 Menu is described by two types of data - menu descriptors and menu items. Descriptor contains
1363 information about following menu items, and items are containing names of entries and either
1364 pointers to functions to execute or, in case of nested menus, pointers to submenu descriptors.
1365 Note that submenu descriptor can be top-level descriptor, there's no difference in structure,
1366 just in the content.
1368 Here is how single descriptor looks like:
1370 void myMenu = {
1371 (char)top, (char)botom, // this is the size of the menubox
1372 (unsigned)left, (unsigned)right, // counting all items in current descriptor
1373 (char)number_of_items | type_of_menu, // number of following items ORed with
1374 // type of this menu, it can be either
1375 // HORIZONTAL or VERTICAL if you will have also bit 6 set then menu won't be closed
1376 // after moving mouse pointer outside the menubox. You can have at most 31 items.
1378 This is followed by <tt/number_of_items/ of following item description.
1381 "menuitemname", (char)item_type, (unsigned)pointer,
1382 "nextitemname", (char)item_type, (unsigned)pointer,
1384 "lastitemname", (char)item_type, (unsigned)pointer };
1385 // Note that there isn't ending <tt/NULL/ or something like that.
1387 <tt/pointer/ is a pointer to something, what it points for depends from <tt/item_type/. This one
1388 can have following values:
1390 <tt/MENU_ACTION/ - a function pointed by <tt/pointer/ will be called after clicking on menu item
1392 <tt/SUB_MENU/ - <tt/pointer/ points to next menu descriptor - a submenu
1394 Both of them can be ORed with <tt/DYN_SUB_MENU/ and then the <tt/pointer/ points to a function
1395 which will return in <tt/r0/ needed pointer (to function to execute or a submenu).
1397 For creating nested menus (you can have at most 8 levels of submenus) you need to declare such
1398 structure for each submenu and top level menu.
1400 <sect2>DoDlgBox command string
1402 <tt/DoDlgBox/ is together with <tt/DoMenu/ one of the most powerful routines in GEOS. It is
1403 responsible for creating dialog boxes, that is windows which task is to interact with user.
1404 Format of the command string is following:
1406 (window size and position)
1407 (commands and parameters)
1410 There is custom type defined for the command string: <tt/dlgBoxStr/.
1412 <sect3>Size and position
1414 The first element can be specified in two ways - by using default size and position or specifying
1415 own. The first case results in
1417 const dlgBoxStr example = {
1418 DB_DEFPOS (pattern_of_shadow),
1422 And the own size and position would be:
1424 const dlgBoxStr example = {
1425 DB_SETPOS (pattern, top, bottom, left, right)
1432 The next element of <tt/DoDlgBox/ command string are commands themselves. First six commands are
1433 default icons and the number of selected icon will be returned from window processor. The icons are
1434 <tt/OK, CANCEL, YES, NO, OPEN/, and <tt/DISK/. You can use predefined macros for use them, e.g.:
1437 DB_ICON(OK, DBI_X_0, DBI_Y_0),
1440 Note that the position is counted from top left corner of window, not entire screen and that the 'x'
1441 position is counted in cards (8-pixel) and not in pixels. This is true also for all following commands.
1442 <tt/DBI_X_0/ and <tt/DBI_Y_0/ are predefined (see <tt/gdlgbox.h/ for more), default positions
1443 which will make icons to appear on default window exactly where you would expect them.
1445 <tt/DB_TXTSTR (x, y, text)/ will cause to show given text in the window.
1447 <tt/DB_VARSTR (x, y, ptr)/ works as above, but here you are passing a pointer to a zero page location
1448 where the address of text is stored. This is useful for information windows where only text content
1449 is variable. Consider following:
1453 r15=(int)text; // in code just before call to DoDlgBox
1455 DB_VARSTR (TXT_LN_X, TXT_LN_1_Y, &r15),
1458 will cause to appear the word ``foo'' in the window, but you may store the pointer to any text in
1459 <tt/r15/ (in this case) before call to DoDlgBox.
1461 <tt/DB_GETSTR(x, y, ptr, length)/ - will add input from keyboard feature. <tt/ptr/ works as in
1462 previous example and points to place where text is to be stored. Note that the contents of this
1463 place will be shown upon creating window. <tt/length/ is the maximum number of characters to input.
1465 <tt/DB_SYSOPV(ptr)/ - this sets <tt/otherPressVec/ to given pointer. It is called on every keypress.
1467 <tt/DB_GRPHSTR(ptr)/ - data for this command is the pointer for <tt/GraphicsString/ commands.
1469 <tt/DB_GETFILES(x, y)/ - for standard window you should pass 4 for both x and y. This function
1470 draws file selection box and searches current drive for files. Before call to <tt/DoDlgBox/ you
1471 must load <tt/r7L/ with GEOS filetype of searched files and <tt/r10/ with class text. In <tt/r5/
1472 you have to load pointer to a <tt/char[17]/ where selected filename will be copied. It works
1473 like <tt/FindFTypes/ but is limited to first 16 files.
1475 <tt/DB_OPVEC(ptr)/ - this sets the new pointer for button press function, if you pass
1476 <tt/RstrFrmDialogue/ here you will cause the window to close after pressing mouse button.
1478 <tt/DB_USRICON(x, y, ptr)/ - places single user icon (click box) on window, <tt/ptr/ points at a
1479 <tt/struct icondef/ but fields <tt/x/ and <tt/y/ are not used here. You can have at most 8 click
1480 boxes in a window, this is internal limit of GEOS Kernal.
1482 <tt/DB_USRROUT(ptr)/ - this command causes to immediately call user routine pointed by <tt/ptr/.
1484 <sect2>GraphicsString command string
1486 <tt/GraphicsString/ is a very powerful routine to initialize whole screen at once. There are
1487 predefined macros for all commands, names are self-explanatory, see them in <tt/ggraph.h/. Last
1488 command have to be <tt/GSTR_END/. There is custom type defined for the command string: <tt/graphicStr/.
1490 Here is an example for clearing the screen:
1492 const graphicStr example = {
1495 RECTANGLETO(319,199)
1499 <sect2>InitRam table
1501 This type of data is used to initialize one or more bytes in many places at once. The format is
1504 void example = {
1505 (unsigned)address_to_store_values_at,
1506 (char)number_of_bytes_that_follow,
1507 (char)data,(char)data (...)
1508 (...) - more such definitions
1509 (unsigned)NULL - address of 0 ends the table