TweetFollow Us on Twitter

Eject the Disk
Volume Number:1
Issue Number:12
Column Tag:Basic School

Building A Library Routine To Eject The Disk

By Dave Kelly, Hybrids Engineer, MacTutor Editorial Board

This months BASIC column features some of the ins and outs of installing your own 68000 code to your MS BASIC programs. The potential power that this provides is mind boggling. With just a few lines of code you can access some of the other ROM routines that are not provided with MS BASIC 2.0.

First off, if you are not already familiar with the Apple Macintosh 68000 Development System then I suggest that you read through the manual to become familiar with the system. In MacTutor Vol. 1 No. 1 the Assembly Language Lab column provides an overview of the MDS system that will be useful for our discussion in this column. It is not necessary that you know 68000 assembly to enter and compile the BASIC Library we will be installing. I will try to lead you through step by step from the point of view of someone that is not very familiar with the MDS system.

Now before we get into the thick of things we will discuss the BASIC LIBRARY statement. The LIBRARY command is a BASIC reserved word but there is no description of it in the BASIC manual other than a brief mention of it on page 103. This page also refers to some special documentation entitled "Microsoft BASIC for the Macintosh -- Building Machine Language Libraries" (hereafter abbreviated as BMLL) which is available by contacting the Microsoft Consumer Response Department. The BMLL document has all the necessary information required to set up your own machine language library and includes 3 sample libraries: CopyFile, PrintArgs, and AddStrings.

A BASIC Library is a Macintosh resource with one or more named CODE segments. Refer to the Inside Macintosh Programmer's Guide section for the definition of the file structure of a resource file. Other sections of Inside Macintosh will be useful in setting up your own routines.

To open a library file you use the statement LIBRARY <filename string expression>. Up to 5 library files may be opened at the same time. When the Library file is opened BASIC calls the routine LIBinit which must exist in each file. The purpose of LIBinit is to allow a way for you to inform BASIC of the compatability of your library routine with the version of BASIC being used. If the library routine is incompatible or the LIBinit routine does not exist or the handshake with that routine fails, then the library is closed and an "Illegal function call" error is generated. This statement can result in other errors which are described in BMLL.

Once the library has been opened the routines within the library may be called by BASIC with the BASIC statements: <routine name> [argument-list] or by CALL <routine name> [(argument-list)]. More on the CALL statement may be found in your BASIC manual starting on page 101.

Constructing a library resource for BASIC

A library is detatched from BASIC whenever NEW, SYSTEM, RUN, or LIBRARY CLOSE is executed. To close the library, BASIC looks for the routine called LIBterm if present and executes it. The routine LIBterm should release any memory which was allocated from the heap, and close any files which were opened by routines in the library. Unless you need to allocate or deallocate memory you probably won't need to use LIBterm.

A sample source file for LIBinit is given with BMLL, but you'll have to work out your own LIBterm if needed depending on the routine you are writing. The sample LIBinit file demonstrates how the routine can check the BASIC version and see if it is compatible with the routines in the library. This sample checks to see that the binary version of BASIC is being used and tells BASIC if it is not compatible. Also included is an equate file named BASIC.D which defines entry points in BASIC which you should use to communicate with BASIC. For my sample library I have included all applicable equates in my source listing so the equate file will not be needed. You will want to use these routines to allocate memory and read the variable argument lists in the BASIC CALL statement. It is advisable that you obtain BMLL before writing your own routines as there are alot of useful routines that can be used that are part of BASIC. BMLL explains what each routine does and what registers are effected.

Alright, now we'll get right down to business. First we need to create several files with the MDS editor which are to be used by the assembler, linker and resource compiler. The two code segments that we want to create are listed below and should be saved with the file names shown. The LIBinit routine will be installed as the first segment and our routine called Eject will be the second segment. Eject will allow you to eject either the internal or external disk from within your program (under BASIC control). Type in the two routines then save them to disk.

Save this routine as "LIBinit.asm".

;
; LIBinit ROUTINE
;Sample version of LIBinit routine
;
;  REGISTER INFORMATION
;
;  A0 = pointer to a version record containing:
;     2 bytes = version of Basic interpreter (ie 2 for 2.01)
;  2 bytes = revision number of Basic interpreter (01)
;  2 bytes = 0 if decimal math, 1 if IEEE binary format
;2 bytes = compatibility variable of this routine to Basic:
;0 = compatible
;-1= incompatible
;8 bytes = reserved array of four INTEGER values
;
; A4 = pointer to a handle (long word) owned by this library
;Use this as a handle to a static data segment.
; A5 = pointer to the base of the application jump table
; D0 = 0 on exit if this routine is purgeable.

LIBVER_Result  EQU 6 ;offset to version record field
 ;for compatibility. (See above)
 
LIBinit:
 CLR.W  LIBVER_Result(A0)       ;assume compatible 
LIBinitExit:
 MOVEQ  #0,D0
 RTS

Here is the Eject Library source code. Save this file as "Eject.asm".

; BASIC Eject Library Source Code
; By Dave Kelly
; MacTutor 1985

;Synopsis:
;CALL Eject ( VolRefNum )
;Output:
;The specified disk is ejected (not dismounted) from
;the selected drive where VolRefNum may be 0 for the
;default drive, 1 for the internal drive, 2 for the
;external drive.

GetNextLibArg  EQU $2A    ; Basic Lib offset from A5
IntegerArgEQU  $32   ; Basic Lib offset from A5
BasicErrorEQU  $42 ; Basic Lib offset from A5

.TRAP _Eject$A000+23 ;toolbox  trap

Ejectdisk:
 BSR  GetIntegerVar;integer arg in [d3:w]
 CMP.W  #0,d3
 BEQ  Doit;branch if on 0 (default drive)
 CMP.W  #1,d3
 BEQ  Doit;branch if on 1 (internal drive)
 CMP.W  #2,d3
 BEQ  Doit;branch if on 2 (external drive)
UnknownVol:
 MOVEQ  #74,d2   ;Unknown Volume error
 JSR  BasicError(a5) 
Doit: 
 LEA  ParamBlock,a0;get pointer
 MOVE.W d3,22(a0);move drive # to ioVRefNum 
 _Eject 
 RTS  
GetIntegerVar:
 JSR  GetNextLibArg(a5) ;Get the next  ;argument
 JSR  IntegerArg(a5) ;[d3:w] = integer ;(error if arg can't be forced 
 ;into an integer
 RTS

;  local data area
 
ParamBlock:
 DC.L 0 ;ioLinkptr.
 DC.W 0 ;ioType
 DC.W 0 ;ioTrap
 DC.L 0 ;ioCmdAddr
 DC.L 0 ;ioCompletionptr.
 DC.W 0 ;ioResult
 DC.L 0 ;ioFileNameptr.
 DC.W 0 ;ioDrvNum (ioVRefNum)

 END

By the way, the Eject routine shows an example of using the file manager parameter block similar to what has been discussed in a few places in the last few MacTutor issues. Refer to those columns for more information. (ie Vol. 1 number 7 & 8)

Next we need to start a new MDS editor file to create a link file for the linker to use. The link shown below should be typed in and saved as "EjectLib.link". Note that if you are not using the default (startup) disk to save these files, the volume name must also be included with the filename.

;Eject Library Link
;MacTutor 1985

/OUTPUT EjectLib
LIBinit.Rel
<
Eject.Rel
$

Now create one last editor file for the Resource compiler. This file creates the resource file that BASIC will call to use the library. Be sure that each line (including the last one) has a carriage return at the end of the line or all the resources may not be compiled. Save this file as "EjectLib.R"

EjectLib.Rsrc
BLIB
TYPE CODE = GNRL
LIBinit,1
.R
EjectLib CODE 1

TYPE CODE = GNRL
Eject,2
.R
EjectLib CODE 2

Ok, we are now ready to assemble our code segments. Assemble LIBinit.asm and Eject.asm by selecting ASM from the MDS system transfer menu or by double clicking on the assembler if you are running the finder desktop. A standard file dialog box will appear and you can select each file and assemble them one at a time. Two new files containing the assembled code are stored on the disk, LIBinit.Rel and Eject.Rel. These two files will be used by the linker to create a linked application file. Select the LINK application from the transfer menu of the MDS system. Note you may have to push the cancel button from the dialog box to get to the transfer menu. The LINKER will create an application to be used by RMAKER. Don't try to run the EjectLib application as it will BOMB!! It only contains resource code segments and is not a regular application program. After linking, select RMAKER from the transfer menu and use the EjectLib.R file to create the resource file to be used by our BASIC library.

Figure 1 shows the files required and the flow of the above procedures. If you have any problems with this then I recommend that you study the MDS system manual and the BMLL supplement.

To try out the Eject Library routine, type in the Eject Demo program. To call the Eject routine, open the Eject Library and then use CALL Eject (VolRefNum). The VolRefNum is a number for the volume which you want to eject. A "0" will eject the disk in the default drive, a "1" will eject the internal drive and "2" will eject the external drive. For any other VolRefNum the file manager returns a unknown volume name error which could be trapped in your BASIC error trap routine if necessary. By the way, using ResEdit you can move the resource segments from the resource files into your BASIC program file (data file where your program is stored). Then the routine can be called by opening up the library with the filename the same as the program. The program would now be completely transportable as one file.

Installing the routines is the easy part. After trying out the demo routines in the BMLL supplement and the Eject routine your mouth may be watering for some more. Well next time we will take a look at some routines which have been prewritten to attach to your BASIC programs allowing access to over a hundred more ROM routines. They are available from a company called Clear Lake Research, 5353 Dora Street #7, Houston, Texas 77005 (1-800-835-2246 X199). If you've felt that BASIC just didn't have enough access to ROM routines then check this one out.

'Eject Library Demo
'By Dave Kelly
'MacTutor ©1985

'Note: EjectLib.Rsrc must be on default disk
'or you must specify vol name in Library statement
LIBRARY  "EjectLib.Rsrc"
'Set up menus
FOR i=1 TO 5
    MENU i,0,0,""
NEXT i
MENU 1,0,1,"File"
MENU 1,1,1,"Quit"
MENU 2,0,1,"Eject Disk"
MENU 2,1,1,"Eject Default Disk"
MENU 2,2,1,"Eject Internal Disk"
MENU 2,3,1,"Eject External Disk"

ON MENU GOSUB Menucheck:MENU ON
pause:GOTO pause

Menucheck:
    menunumber = MENU(0)
    menuitem=MENU(1):MENU
    IF menunumber = 1 THEN filemenu
    IF menunumber <>2 THEN RETURN
    IF menuitem = 1 THEN vol= 0
    IF menuitem = 2 THEN vol = 1
    IF menuitem = 3 THEN vol = 2
    CALL Eject (vol)
    RETURN
    
filemenu:
    IF menuitem <> 1 THEN RETURN
    MENU RESET:LIBRARY CLOSE:END

Thanks go to Robert Millis for sending us an improvement to the Cursor Editor routine in the August '85 issue. Due to editorial deadlines it is not possible to streamline all the code used in each issue for maximum efficiency. We do try to make sure that each and every program works. Keep in mind also that the code for most of the columns must be edited to fit properly. The programs are run before editing and placed on the source disks which you may order from us. We encourage you to modify and improve our programs. Please feel encouraged to send us any improvements that you have made so that our other readers may also benefit. The following code may replace the getpixel routine in the August Cursor Editor for improved speed and usability of the program:

getpixel: 'For Cursor Editor
    pixel%=256
    xp=MOUSE(1):yp=MOUSE(2)
    IF xp<20 OR xp>196 THEN RETURN
    IF yp<20 OR yp>196 THEN RETURN
    row=INT((yp-20)/11):col = INT((xp-20)/11)
    pixel%=row*16+(15-col)
    RETURN

It should be noted that the same routine was used in the September Paint Pattern Editor with some minor differences. Don't mix them up; they are different. The following code may replace the getpixel routine in Paint Pattern Editor:

getpixel: 'For Paint Pattern Editor
    pixel%=64
    xp=MOUSE(1):yp=MOUSE(2)
    IF xp<20 OR xp>108 THEN RETURN
    IF yp<20 OR yp>108 THEN RETURN
    row=INT((yp-20)/11):col = INT((xp-20)/11)
    pixel%=row*8+(7-col)
    RETURN
 

Community Search:
MacTech Search:

Software Updates via MacUpdate

GraphicConverter 10.5.1 - $39.95
GraphicConverter is an all-purpose image-editing program that can import 200 different graphic-based formats, edit the image, and export it to any of 80 available file formats. The high-end editing... Read more
Delicious Library 3.7 - Import, browse a...
Delicious Library allows you to import, browse, and share all your books, movies, music, and video games with Delicious Library. Run your very own library from your home or office using our... Read more
Adobe Animate CC 2017 18.0.0.107 - Anima...
Animate CC 2018 is available as part of Adobe Creative Cloud for as little as $19.99/month (or $9.99/month if you're a previous Flash Professional customer). Animate CC 2018 (was Flash CC) lets you... Read more
Adobe After Effects CC 2018 15.0 - Creat...
After Effects CC 2018 is available as part of Adobe Creative Cloud for as little as $19.99/month (or $9.99/month if you're a previous After Effects customer). The new, more connected After Effects CC... Read more
Adobe Premiere Pro CC 2018 12.0.0 - Digi...
Premiere Pro CC 2018 is available as part of Adobe Creative Cloud for as little as $19.99/month (or $9.99/month if you're a previous Premiere Pro customer). Adobe Premiere Pro CC 2018 lets you edit... Read more
Alarm Clock Pro 10.3 - $19.95
Alarm Clock Pro isn't just an ordinary alarm clock. Use it to wake you up in the morning, send and compose e-mails, remind you of appointments, randomize the iTunes selection, control an internet... Read more
Adobe Lightroom 20170919-1412-ccb76bd] -...
Adobe Lightroom is available as part of Adobe Creative Cloud for as little as $9.99/month bundled with Photoshop CC as part of the photography package. Lightroom 6 is also available for purchase as a... Read more
Adobe Illustrator CC 2018 22.0.0 - Profe...
Illustrator CC 2018 is available as part of Adobe Creative Cloud for as little as $19.99/month (or $9.99/month if you're a previous Illustrator customer). Adobe Illustrator CC 2018 is the industry... Read more
Hopper Disassembler 4.3.0- - Binary disa...
Hopper Disassembler is a binary disassembler, decompiler, and debugger for 32- and 64-bit executables. It will let you disassemble any binary you want, and provide you all the information about its... Read more
Adobe InDesign CC 2018 13.0.0.125 - Prof...
InDesign CC 2018 is available as part of Adobe Creative Cloud for as little as $19.99/month (or $9.99/month if you're a previous InDesign customer). Adobe InDesign CC 2018 is part of Creative Cloud.... Read more

ICEY (Games)
ICEY 1.0 Device: iOS Universal Category: Games Price: $2.99, Version: 1.0 (iTunes) Description: ICEY is a 2D side-scrolling action game. As you follow the narrator's omnipresent voice, you will see through ICEY's eyes and learn the... | Read more »
The best new games we played this week -...
We've made it, folks. Another weekend is upon us. It's time to sit back and relax with the best new releases of the week. Puzzles, strategy RPGs, and arcade games abound this week. There's a lot of quality stuff to unpack this week, so let's hop... | Read more »
Wheels of Aurelia (Games)
Wheels of Aurelia 1.0.1 Device: iOS Universal Category: Games Price: $3.99, Version: 1.0.1 (iTunes) Description: | Read more »
Halcyon 6: Starbase Commander guide - ti...
Halcyon 6 is a well-loved indie RPG with stellar tactical combat and some pretty good writing, too. It's now landed on the App Store, so mobile fans, if you're itching for a good intergalactic adventure, here's your game. Being a strategy RPG, the... | Read more »
Game of Thrones: Conquest guide - how to...
Fans of base building games might be excited to know that yet another entry in the genre has materialized - Game of Thrones: Conquest. Yes, you can now join the many kingdoms of the famed book series, or create your own, as you try to conquer... | Read more »
Halcyon 6: Starbase Commander (Games)
Halcyon 6: Starbase Commander 1.4.2.0 Device: iOS Universal Category: Games Price: $6.99, Version: 1.4.2.0 (iTunes) Description: An epic space strategy RPG with base building, deep tactical combat, crew management, alien diplomacy,... | Read more »
Legacy of Discord celebrates its 1 year...
It’s been a thrilling first year for fans of Legacy of Discord, the stunning PvP dungeon-crawling ARPG from YOOZOO Games, and now it’s time to celebrate the game’s first anniversary. The developers are amping up the festivities with some exciting... | Read more »
3 reasons to play Thunder Armada - the n...
The bygone days of the Battleship board game might have past, but naval combat simulators still find an audience on mobile. Thunder Armada is Chinese developer Chyogames latest entry into the genre, drawing inspiration from the explosive exchanges... | Read more »
Experience a full 3D fantasy MMORPG, as...
Those hoping to sink their teeth into a meaty hack and slash RPG that encourages you to fight with others might want to check out EZFun’s new Eternity Guardians. Available to download for iOS and Android, Eternity Guardians is an MMORPG that lets... | Read more »
Warhammer Quest 2 (Games)
Warhammer Quest 2 1.0 Device: iOS Universal Category: Games Price: $4.99, Version: 1.0 (iTunes) Description: Dungeon adventures in the Warhammer World are back! | Read more »

Price Scanner via MacPrices.net

9″ iPads on sale for $30 off, starting at $29...
MacMall has 9″ iPads on sale for $30 off including free shipping: – 9″ 32GB iPad: $299 – 9″ 128GB iPad: $399 Read more
Apple restocks full line of refurbished 13″ M...
Apple has restocked a full line of Apple Certified Refurbished 2017 13″ MacBook Pros for $200-$300 off MSRP. A standard Apple one-year warranty is included with each MacBook, and shipping is free.... Read more
13″ 3.1GHz/256GB MacBook Pro on sale for $167...
Amazon has the 2017 13″ 3.1GHz/256GB Space Gray MacBook Pro on sale today for $121 off MSRP including free shipping: – 13″ 3.1GHz/256GB Space Gray MacBook Pro (MPXV2LL/A): $1678 $121 off MSRP Keep an... Read more
13″ MacBook Pros on sale for up to $120 off M...
B&H Photo has 2017 13″ MacBook Pros in stock today and on sale for up to $120 off MSRP, each including free shipping plus NY & NJ sales tax only: – 13-inch 2.3GHz/128GB Space Gray MacBook... Read more
15″ MacBook Pros on sale for up to $200 off M...
B&H Photo has 15″ MacBook Pros on sale for up to $200 off MSRP. Shipping is free, and B&H charges sales tax in NY & NJ only: – 15″ 2.8GHz MacBook Pro Space Gray (MPTR2LL/A): $2249, $150... Read more
Roundup of Apple Certified Refurbished iMacs,...
Apple has a full line of Certified Refurbished 2017 21″ and 27″ iMacs available starting at $1019 and ranging up to $350 off original MSRP. Apple’s one-year warranty is standard, and shipping is free... Read more
Sale! 27″ 3.8GHz 5K iMac for $2098, save $201...
Amazon has the 27″ 3.8GHz 5K iMac (MNED2LL/A) on sale today for $2098 including free shipping. Their price is $201 off MSRP, and it’s the lowest price available for this model (Apple’s $1949... Read more
Sale! 10″ Apple WiFi iPad Pros for up to $100...
B&H Photo has 10.5″ WiFi iPad Pros in stock today and on sale for $50-$100 off MSRP. Each iPad includes free shipping, and B&H charges sales tax in NY & NJ only: – 10.5″ 64GB iPad Pro: $... Read more
Apple iMacs on sale for up to $130 off MSRP w...
B&H Photo has 21-inch and 27-inch iMacs in stock and on sale for up to $130 off MSRP including free shipping. B&H charges sales tax in NY & NJ only: – 27″ 3.8GHz iMac (MNED2LL/A): $2179 $... Read more
2017 3.5GHz 6-Core Mac Pro on sale for $2799,...
B&H Photo has the 2017 3.5GHz 6-Core Mac Pro (MD878LL/A) on sale today for $2799 including free shipping plus NY & NJ sales tax only . Their price is $200 off MSRP. Read more

Jobs Board

*Apple* Retail - Multiple Positions - Apple,...
Job Description: Sales Specialist - Retail Customer Service and Sales Transform Apple Store visitors into loyal Apple customers. When customers enter the store, Read more
Commerce Engineer, *Apple* Media Products -...
Commerce Engineer, Apple Media Products (New York City) Job Number: 113028813New York City, New York, United StatesPosted: Sep. 20, 2017Weekly Hours: 40.00 Job Read more
US- *Apple* Store Leader Program - Apple (Un...
US- Apple Store Leader Program Job Number: VariousUnited StatesPosted: Oct. 19, 2017Retail Store Job Summary Learn and grow as you explore the art of leadership at Read more
Product Manager - *Apple* Pay on the *Appl...
Job Summary Apple is looking for a talented product manager to drive the expansion of Apple Pay on the Apple Online Store. This position includes a unique Read more
*Apple* Retail - Multiple Positions - Farmin...
Sales Specialist - Retail Customer Service and Sales Transform Apple Store visitors into loyal Apple customers. When customers enter the store, you're also the Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.