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

Capto 1.2.9 - $29.99
Capto (was Voila) is an easy-to-use app that takes capturing, recording, video and image editing to the next level. With an intelligent file manager and quick sharing options, Capto is perfect for... Read more
Opera 51.0.2830.40 - High-performance We...
Opera is a fast and secure browser trusted by millions of users. With the intuitive interface, Speed Dial and visual bookmarks for organizing favorite sites, news feature with fresh, relevant content... Read more
GarageSale 7.0.13 - Create outstanding e...
GarageSale is a slick, full-featured client application for the eBay online auction system. Create and manage your auctions with ease. With GarageSale, you can create, edit, track, and manage... Read more
1Password 6.8.7 - Powerful password mana...
1Password is a password manager that uniquely brings you both security and convenience. It is the only program that provides anti-phishing protection and goes beyond password management by adding Web... Read more
Evernote 7.0.1 - Create searchable notes...
Evernote allows you to easily capture information in any environment using whatever device or platform you find most convenient, and makes this information accessible and searchable at anytime, from... Read more
MacUpdate Desktop 6.2.0 - $20.00
MacUpdate Desktop brings seamless 1-click app installs and version updates to your Mac. With a free MacUpdate account and MacUpdate Desktop 6, Mac users can now install almost any Mac app on... Read more
HoudahSpot 4.3.5 - Advanced file-search...
HoudahSpot is a versatile desktop search tool. Use HoudahSpot to locate hard-to-find files and keep frequently used files within reach. HoudahSpot will immediately feel familiar. It works just the... Read more
EtreCheck 4.0.4 - For troubleshooting yo...
EtreCheck is an app that displays the important details of your system configuration and allow you to copy that information to the Clipboard. It is meant to be used with Apple Support Communities to... Read more
WhatsApp 0.2.8361 - Desktop client for W...
WhatsApp is the desktop client for WhatsApp Messenger, a cross-platform mobile messaging app which allows you to exchange messages without having to pay for SMS. WhatsApp Messenger is available for... Read more
iClock 4.2 - Customize your menubar cloc...
iClock is a menu-bar replacement for Apple's default clock but with 100x features. Have your Apple or Google calendar in the menubar. Have the day, date, and time in different fonts and colors in the... Read more

Latest Forum Discussions

See All

The best games like Florence
Florence is a great little game about relationships that we absolutely adored. The only problem with it is it's over a little too soon. If you want some other games with some emotional range like Florence, check out these suggestions: [Read more] | Read more »
Angry Birds Champions adds cash prizes t...
Collaborating with developer Rovio Entertainment, GSN Games has released a twist on the Angry Birds formula. Angry Birds Champions features the same bird-flinging gameplay, but now you can catapult Red and co for cash. | Read more »
Around the Empire: What have you missed...
148Apps is part of a family. A big family of sites that make sure you're always up to date with all the portable gaming news. Just like a real family, I guess. I don't know, my mum never told me anything about Candy Crush to be fair. [Read more] | Read more »
The Battle of Polytopia Guide - Tips for...
The addition of multiplayer to The Battle of Polytopia has catapulted the game from a fun enough time waster to a fully-fledged 4X experience on your phone. We've been playing quite a few matches over the past week or so, and we've put together a... | Read more »
All the best games on sale for iPhone an...
Hi there, and welcome to our round up of all the best games that are on sale for iOS at the moment. It's not a vintage week in terms of numbers, but I'm pretty sure that every single one of these is worth picking up if you haven't already played... | Read more »
Disc Drivin' 2 Guide - Tips for the...
We're all still playing quite a bit of Disc Drivin' 2 over here at 148Apps, and we've gotten pretty good at it. Now that we've spent some more time with the game and unlocked more powerups, check out some of these more advanced tips: | Read more »
Alto's Odyssey Guide - How to Tackl...
Alto’s Odyssey is a completely stunning and serene runner, but it can also be a bit tricky. Check out these to try and keep your cool while playing this endless runner: Don’t focus too much on tasks [Read more] | Read more »
Here's everything you need to know...
Alto's Odyssey is a really, really good game. If you don't believe me, you should definitely check out our review by clicking this link right here. It takes the ideas from the original Alto's Adventure, then subtly builds on them, creating... | Read more »
Alto's Odyssey (Games)
Alto's Odyssey 1.0.1 Device: iOS Universal Category: Games Price: $4.99, Version: 1.0.1 (iTunes) Description: Just beyond the horizon sits a majestic desert, vast and unexplored. Join Alto and his friends and set off on an endless... | Read more »
Vainglory 5v5: Everything you need to kn...
Vainglory just got bigger. [Read more] | Read more »

Price Scanner via MacPrices.net

Apple AirPods in stock today for $159, free s...
Adorama reports stock of Apple AirPods today for $159 including free shipping, plus pay no sales tax outside of NY & NJ. See our Apple AirPod Price Tracker for the latest prices and stock status... Read more
Saturday Sale: Amazon offers 12″ 1.3GHz MacBo...
Amazon has Silver and Gold 2017 12″ 1.3GHz Retina MacBooks on sale for $250 off MSRP. Shipping is free: – 12″ 1.3GHz Silver MacBook: $1349.99 $250 off MSRP – 12″ 1.3GHz Gold MacBook: $1349.99 $250... Read more
Use your Apple Education discount and save up...
Purchase a new Mac using Apple’s Education discount, and take up to $400 off MSRP. All teachers, students, and staff of any educational institution with a .edu email address qualify for the discount... Read more
Apple Canada offers 2017 21″ and 27″ iMacs fo...
 Canadian shoppers can save up to $470 on the purchase of a 2017 current-generation 21″ or 27″ iMac with Certified Refurbished models at Apple Canada. Apple’s refurbished prices are the lowest... Read more
9″ iPads available online at Walmart for $50...
Walmart has 9.7″ Apple iPads on sale for $50 off MSRP for a limited time. Sale prices are for online orders only, in-store prices may vary: – 9″ 32GB iPad: $279.99 $50 off – 9″ 128GB iPad: $379.99 $... Read more
15″ Apple MacBook Pros, Certified Refurbished...
Save $360-$420 on the purchase of a 2017 15″ MacBook Pro with Certified Refurbished models at Apple. Apple’s refurbished prices are the lowest available for each model from any reseller. An standard... Read more
Amazon restocks MacBook Pros with models avai...
Amazon has restocked 15″ and 13″ Apple MacBook Pros with models on sale for up to $251 off MSRP. Shipping is free. Note that stock of some Macs may come and go (and some sell out quickly), so check... Read more
Lowest price of the year: 15″ 2.8GHz Apple Ma...
Amazon has the 2017 Space Gray 15″ 2.8GHz MacBook Pro on sale today for $251 off MSRP. Shipping is free: – 15″ 2.8GHz Touch Bar MacBook Pro Space Gray (MPTR2LL/A): $2148, $251 off MSRP Their price is... Read more
Apple restocks full line of Certified Refurbi...
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
Lowest sale price available for 13″ 1.8GHz Ma...
Focus Camera has the 2017 13″ 1.8GHz/128GB Apple MacBook Air on sale today for $829 including free shipping. Their price is $170 off MSRP, and it’s the lowest price available for a current 13″... Read more

Jobs Board

*Apple* Media Products Commerce Engineering...
# Apple Media Products Commerce Engineering Manager Job Number: 56207285 Santa Clara Valley, California, United States Posted: 26-Jan-2018 Weekly Hours: 40.00 **Job Read more
Digital Platforms Lead, Today at *Apple* -...
# Digital Platforms Lead, Today at Apple Job Number: 56178747 Santa Clara Valley, California, United States Posted: 23-Feb-2018 Weekly Hours: 40.00 **Job Summary** Read more
*Apple* Retail - Multiple Positions - Apple,...
Job Description:SalesSpecialist - Retail Customer Service and SalesTransform Apple Store visitors into loyal Apple customers. When customers enter the store, Read more
*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
*Apple* Retail - Multiple Positions - Apple,...
Job Description:SalesSpecialist - Retail Customer Service and SalesTransform Apple Store visitors into loyal Apple customers. When customers enter the store, Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.