TweetFollow Us on Twitter

Forth Updates
Volume Number:2
Issue Number:5
Column Tag:Threaded Code

Updates for Mach1 and Neon

By Jörg Langowski, EMBL, C/O I.L.L., Grenoble, Cedex, France, MacTutor Editorial Board

"In Our Mail"

This time, I have no specific subject to cover, but would rather like to address a few points that came up while browsing through my mail lately. Also, I want to inform you on updates of NEON and Mach1 that just came in. (Judging from the productivity of some of the developers, the next updates will probably be out even before this comes back from the printer's...)

We received a letter from Finland; Juri Munkki from Helsinki sent the following interesting note:

"I received my HD 20 yesterday and I found some problems with using it for Forth development using MacForth Level 3. The problems arise when trying to access files from directories outside the Forth folder [this seems to be one of the standard problems in HFS. J.L.]. I was very glad to see that my terminal program worked correctly with HFS and used that knowledge to add a new command to MacForth.

MacForth activates windows automatically when an activation event is received. This is not desirable when returning from a standard file-call because it interrupts the execution of the calling program. Before receiving Level 3, I used a special window for calling the standard file package and used two different activate procedures. Level 3 documentation explained the Event.Table and I was capable of simplifying the calling of these extremely important routines.

The main reason my program worked was that it used PBSetVol to change the default directory. This simple technique of calling SetVol after SFGetFile and PutFile allows me to use standard MacForth file commands without any modification of the internal structure FCBs.

The routine below [Listing 1] fits in one block (if left without comments) and is very helpful in using the HFS folders. "

Listing 1 : Select directory, by Juri Munkki

( Directory Mount utility)                     ( 011086 JAM)
create SFReply 76 allot
 SFReply 76 erase  ( standard file reply record)
create OurParams 32 allot
 OurParams 32 erase   ( our param block)
hex  A015  os.trap  SetVol   ( PBSetVol  OS  trap )
   A9EA  w>mt    Pack3    ( standard file package)
variable  act.ev.proc   ( standard action for activate )

: seldir ( lets the user choose a default directory )
 activate.event 2* event.table + w@ act.ev.proc !
 ( save old activate.event vector )
0 activate.event 2* event.table + w!
 ( disable vector temporarily )

 00400040 "  " 0 -1 0 wbury 0 0 sfreply 2 pack3
 ( call SFGetfile)
 act.ev.proc @ activate.event 2* event.table + w!
 ( reset activate vector)

 SFReply c@ if  ( file was selected)
 SFReply 6+ w@ OurParams 16 + w! 
 OurParams SetVol then
;

axe SetVol  axe Pack3  axe act.ev.proc  
axe SFReply  axe OurParams
decimal

"Just type SelDir and choose a file from the directory you want to work with. This directory is automatically vref 0 and can be shown by typing 0 dir. I thought that you might find this information useful to some MacTutor readers. "

Yes, we do, thank you for that contribution! I tested that routine - not using HFS, since I don't have 800K disks or a hard disk yet - but to change the default drive. After executing SelDir (e.g. on a file in the external drive), both 0 dir and 2 dir will display the external directory, and files without directory prefix will be looked for on the external drive. Saves a lot of hassle when one loads files from the external drive that include" files that are also on the external drive.

Indirect recursion and deferred execution

Another letter comes from Steve Pothier in Tucson, AZ, asking a question about recursion in NEON. I made a comment in the NEON article (MT V2#1) about the use of the forward declaration in recursion, which I did not further explain, so here goes:

As a matter of fact, simple recursion is generally allowed in NEON, while this is not the case in MacForth. As said in the mentioned article, one can circumvent this problem by resetting the smudge bit during compilation. Mach1 has the word recursive built in which does exactly this job, so the corresponding definition of the factorial would be:

: factorial   ( Mach 1 version )
 recursive
 dup if dup 1 - factorial * else drop 1 then ;

So we're pretty fine in any kind of Forth doing direct recursion, that is to say referencing a Forth word from within its own definition. However, indirect recursion is a different ballgame. If we want to reference word A from word B, which contains a reference to word A in its definition, we will have to reference one of the two words before it is actually defined. This is, of course, not possible in Forth. But the problem can be solved.

Lets assume we define routine A first, then routine B. Then the only way to refer to B from within A is to create a vector B.vect before defining A, referring from within A to B.vect instead of B, and setting the vector after having defined B. Lots of As and Bs here, an example will illustrate:

create B.vect ( and do something with it ...)
.... code to initialize the vector ....

: A .......
      .......   B.vect ( B is called here )
      .......  
;
: B .......
      .......  A  ( may be called in the normal way )
      .......  
;
.... code to setup B.vect so that it executes B when called ....

How do we do this in practice? NEON has the forward declaration built in. In case one needs to refer to a word that cannot be defined yet, one can 'pre-declare' this word by saying forward B and then using this definition of B in any other words following it. When one is ready to define B, the special defining word :F together with ;F is used to resolve the forward reference. As long as this has not been done, any attempt to execute B will result in an error message. The example from above then looks like the following in NEON:

forward B

: A .......
      .......   B ( B is called here just like any word )
      .......  
;

:F B ....... 
       .......  A  ( called in the normal way )
       .......  
;F 
( forward reference is resolved after this definition)

Standard Forth (-79 or -83) does not have a forward declaration built in. MacForth and Mach1 don't have it. MasterFORTH has defer, which does a similar thing as forward, defining a word whose action will be defined later. defer and related words are explained in the book 'Mastering Forth' that comes with the MasterFORTH package:

: undef.error ." not defined yet! " cr ;

: defer  create ['] undef.error ,
 does> @ execute ;

: is ' >body ! ;

defer is a compiling word whose runtime action is to execute the vector that it contains. Initially, this vector is set to the address of a warning message that is printed as long as the word has not been defined yet.

is stores the address on the stack into the body (Forth-83) of the word following it. This means if we define

defer my.vector
: test ." Hello world!" cr ;

and then say

' test is my.vector

execution of my.vector will result in "Hello world" being printed.

Now our indirect-recursion example from above would look like:

defer B.vect

: A .......   B.vect   ....... ;

: B .......  A  ....... ;

' B is B.vect 

Notice that these definitions are for MasterFORTH; Mach1 has a different structure (explained in my last column), and the definition of is has to be changed:

: is ( Mach1 version )  ' 4 + ! ;

MacForth has an even different structure; the corresponding definitions would look like:

: undef.error ." not defined yet!" cr ;                         
                                                                
: defer 
        create ' undef.error ,                                  
        does> @ >r ;                                            
                                                                
: is [compile] ' ! ;                                            

For MacForth, I have also given an example of Leo Brodie's DOER/MAKE vectored execution handler (V1#7). DOER/MAKE, of course, allows also for deferred execution, e.g.

doer B.vect

: A .......   B.vect    .......  ;

: B .......   A    .......  ;

make B.vect B

with the additional advantage that vectors can be made to execute other words from within definitions. I won't give the corresponding definitions of DOER/MAKE for Mach1 or MasterFORTH here; this is, as they say, left as an exercise for the reader.

Upgrades, improvements etc.

I just received updates of NEON (v 1.5) and Mach (Mach 1.1) in the mail. Many of the bugs that were still present in the first versions of these systems have been removed. Let me just give you an extract of the information that was sent to me together with the updates by Palo Alto Shipping and Kriya:

Mach 1.1

[excerpts from the letter by Palo Alto Shipping]

"MACH 1.1 SUPPORTS MACPLUS AND HFS

MACH 1.1 includes support for the new trap routines included in the new 128K roms and works under the Hierarchical File System. SWITCHER 4.6 is also included.

DEBUGGER REMOVED

A debugger is no longer included in MACH 1 for two reasons. One reason is that there is currently an abundance of inexpensive, high quality debuggers for the Macintosh. The second reason is that since the debugger was written in MACH 1, its performance was very dependent upon the integrity of the MACH 1 kernel. If the kernel ever became damaged, the debugger would often fail. The debugger chapter in the manual should be disregarded. [Too bad that this part of the system is gone. The single stepping mode with the ability to see Forth and machine code simultaneously was a nice feature. However, the debugger had its own bugs... Palo Alto Shipping is working on an improved version and planning to reinstall the debugger on future systems]

Note that the dissassembler is still included. [from which the addressing mode bugs mentioned in my last column have been removed / J.L.]

NEW WORDS

Six new words which run the default event-handling routines when executed have been added to the MACH 1 kernel. [to be used to stash into deferred execution vectors etc... / J.L.]

The following words which support the printing manager have been added to MACH1: [...]

PrCtlCall PrDrvrClose PrDrvrOpen

PrSetError PrError PrPicFile PrCloseDoc

PrClosePage PrOpenPage PrOpenDoc

PrJobMerge PrJobDialog PrStlDialog

PrValidate PrintDefault PrClose PrOpen

That's for the Mach1.1 update. It seems to me that with the extra printer support the spooler example form my last column could be upgraded into a real nice background spooler for Text and Paint files. The upgrade furthermore contains a second disk packed full of demos, some of which are rather sophisticated application examples (e.g. a TextEdit example and one that uses the printing routines). Also includes is a 3-d fractal demo that draws mountain shapes. Nice to look at.

NEON 1.5

The main additions to the new NEON 1.5 are listed below [words by Kriya Systems]:

"Here are the functional differences between Neon v1.0 and v1.5. [ ]

Features added:

• Floating Point support; use "neonFP.com"

• All source for rebuilding Neon up from the nucleus is released

• New classes have been included: LinkedList, 2dArray, Dictionary, etc

• New utilities have been included: Decompile, PrintAll, Words, etc

[The Decompiler supplied by Kriya works only on Colon definitions. One that gives also at least some informations about class definitions is still a project for this column. / J.L.]

• Neon™ v1.5 is compatible with the new Neon™ Assembler

• SORT is a new word which performs a shell sort

• $= is a new word which performs a relative compare on strings

• LAND, LOR & LXOR are new words which are the logical counterparts to the bitwise AND, OR & XOR

• PUSHPORT & POPPORT are new words for keeping graph port record pointers on the data stack

• PARAMTEXT is a new word for use with dialogs which sets text substitution strings for Static and Editable text items

• CALLER is a new pseudo-ivar, like SELF or SUPER, which late binds a message to the calling object. (This must be used inside a method.)

• The fill: method has been added to String

• A disp: method has been added to each of Picture, Alert, Rect & Icon

• The putText: & getText: methods of Dialog now work on control items

• The status of the cursor is now preserved during Neon functions

• You may now grow the Neon window to the full size of a MacXL screen

• Compile echo now functions for modules

• WORDS now formats it's output according to the width of the window

• The Install dialog now includes the "Max Heap" button

Bugs fixed:

• The name field for SIGN is fixed and is now findable

• The U* presicion bug has been fixed; (*/ & M* also)

• PURGE has been modified to work on megabyte Macs

• The fill: & new: methods of Array have been fixed

• The put: & click: methods of Mouse have been fixed

• The charOf: method of String has been fixed

• The print: method of Timer has been fixed

• The baud: method of Port cleans up the stack properly

Functions changed:

• FINFO returns a relative address

• STDGET takes a specification of up to four file types

• The words MLOCK, MUNLOCK & ?MLOCK now take the cfa of a module

• NULL & BYE are now defined above the nucleus so that they may be called from menu selections defined through the use of getMtxt.

[Before, it was very important when making stand-alone applications, to define 'calling words' for BYE and NULL, which were part of the nucleus, and use those 'super-definitions' in menu files. Otherwise, the menu handler would not find the NEON word corresponding to the menu item when the menu text was loaded at runtime, causing a crash. This was the reason for the crash of my text edit example in the Feb 86 issue; I forgot to include a new definition for NULL just like the CIAO definition for BYE]

• The word FF (form feed) has been renamed to NP (new page)

• QUIT now clears menu bar hilites

• The Grep utility now prints the file name only when a match occurs

• ASCII no longer shifts alphabetics to upper case

• The grow: method of Window does not clear the window

• The actions: method of vScroll has a clear: parts

• The Apple menu now accomodates up to 22 items".

[Other observations:

• Quitting NEON with the Editor still open and relaunching from the desktop no longer causes a crash.

• The bug in IC! (this word simply didn't work under NEON 1.0) is still there!. The Sieve example (see MT V1#8, p.18) still works only when IC! is replaced by I C!. -J.L.]

Since I have not upgraded my systems to the large drive, new ROMs and HFS yet (I'm reluctant to do so as long as there is no working version of Fortran available for HFS), I cannot judge whether NEON 1.5 will work correctly with the new system. Any comments on this by readers will be greatly appreciated.

The fix for IC!

Since Kriya Systems don't seem to have noticed, here's my fix for IC!, which makes this word work correctly (did this by disassembling the kernel and looking through the file with Fedit):

The code that has to be fixed starts at relative address $13B4 (absolute $E044 in my system) in both NEON 1.0 and NEON 1.5:

13B4: 2E16 MOVE.L (A6), D7

13B6: 568F ADDQ.L #3,A7

13B8: 179F 7800 MOVE.B (A7)+, 0(A3,D7)

13BC: 2C1C MOVE.L (A4)+, D6

13BE: 2E33 6800 MOVE.L 0(A3,D6), D7

13C2: 4EF3 JMP 0(A3,D7)

For some reason, the ADDQ in connection with the MOVE.B does not seem to do its intended job (Can anyone help me; 68000 machine code specialists, please). The code works if you change it to:

13B4: 2E16 MOVE.L (A6), D7

13B6: 201F MOVE.L (A7)+, D0

13B8: 1780 7800 MOVE.B D0, 0(A3,D7)

13BC: 2C1C MOVE.L (A4)+, D6

13BE: 2E33 6800 MOVE.L 0(A3,D6), D7

13C2: 4EF3 JMP 0(A3,D7)

The way to install this patch permanently is by using Fedit or some similar program. Open the NEON file and search for the hex sequence 568F179F. Verify by looking at the code around it that you have really found the correct piece of code. Then replace this sequence by 201F1780. Now rewrite the sector to your disk (HOLD IT! You did make a backup first, I suppose?). This should give you a working IC! in your NEON kernel.

Questions, comments etc. may now also be addressed to: LANGOWSKI@DHDEMBL5 on BITNET, or, if you are using BYTE's BIX system, you can leave mail under JLANGOWSKI for me or MACTUTOR for David Smith.

See you in a month.

 

Community Search:
MacTech Search:

Software Updates via MacUpdate

Apple Security Update 2015-005 - For OS...
Apple Security Update 2015-005 is recommended for all users and improves the security of OS X. For detailed information about the security content of this update, please visit: http://support.apple.... Read more
Apple HP Printer Drivers 3.1 - For OS X...
Apple HP Printer Drivers includes the latest HP printing and scanning software for OS X Lion or later. For information about supported printer models, see this page. Version 3.1: The latest printing... Read more
Epson Printer Drivers 3.1 - For OS X 10....
Epson Printer Drivers installs the latest software for your EPSON printer or scanner for OS X Yosemite, OS X Mavericks, OS X Mountain Lion, and OS X Lion. For more information about printing and... Read more
Xcode 6.4 - Integrated development envir...
Xcode provides everything developers need to create great applications for Mac, iPhone, and iPad. Xcode brings user interface design, coding, testing, and debugging into a united workflow. The Xcode... Read more
OS X Yosemite 10.10.4 - Apple's lat...
OS X Yosemite is Apple's newest operating system for Mac. An elegant design that feels entirely fresh, yet inherently familiar. The apps you use every day, enhanced with new features. And a... Read more
Dash 3.0.2 - Instant search and offline...
Dash is an API Documentation Browser and Code Snippet Manager. Dash helps you store snippets of code, as well as instantly search and browse documentation for almost any API you might use (for a full... Read more
FontExplorer X Pro 5.0 - Font management...
FontExplorer X Pro is optimized for professional use; it's the solution that gives you the power you need to manage all your fonts. Now you can more easily manage, activate and organize your... Read more
Typinator 6.6 - Speedy and reliable text...
Typinator turbo-charges your typing productivity. Type a little. Typinator does the rest. We've all faced projects that require repetitive typing tasks. With Typinator, you can store commonly used... Read more
Arq 4.12.1 - Online backup to Google Dri...
Arq is super-easy online backup for the Mac. Back up to your own Google Drive storage (15GB free storage), your own Amazon Glacier ($.01/GB per month storage) or S3, or any SFTP server. Arq backs up... Read more
Gutenprint 5.2.11-pre1 - Quality drivers...
Gutenprint is a suite of printer drivers that may be used with most common UNIX print spooling systems, including CUPS, lpr, LPRng, or others. Gutenprint currently supports over 2000 printer models.... Read more

Vector 2 is Officially a Thing and it...
Vector is a pretty cool parkour-driven runner that's gotten a pretty decent following since it first came out - although personally I think more people could stand to show it some love. Anyway, Nekki has announced that a sequel isofficially on its... | Read more »
This Week at 148Apps:June 22-26, 2015
June's Summer Journey Continues With 148Apps How do you know what apps are worth your time and money? Just look to the review team at 148Apps. We sort through the chaos and find the apps you're looking for. The ones we love become Editor’s Choice,... | Read more »
LEGO® Minifigures Online (Games)
LEGO® Minifigures Online 1.0.1 Device: iOS iPhone Category: Games Price: $4.99, Version: 1.0.1 (iTunes) Description: | Read more »
World of Tanks Blitz celebrates its firs...
Today marks the first anniversary of the launch of World of Tanks Blitz, the mobile version of the PC tank battler, World of Tanks. World of Tanks Blitz launched on iOS and Android on June 26th last year and to celebrate, Wargaming is giving all... | Read more »
Heroes and Castles 2 Has its Own Standal...
Heroes and Castles 2 is a third-person castle defense game from the same team behind Block Fortress and Bug Heroes. It's cool, it's fun, and now it has its very own free version. [Read more] | Read more »
Formula Cartoon All-Stars Lets You Race...
Ever want to pit your favorite characters from shows like Steven Universe, Adventure Time, and Regular Show against each other in a not quite death race? Well once upon a time you could, but Formula All Stars Touch N' Go doesn't exist anymore. Hope... | Read more »
Retype - Typography Photo Editor (Photo...
Retype - Typography Photo Editor 1.0 Device: iOS Universal Category: Photography Price: $2.99, Version: 1.0 (iTunes) Description: Retype is built out of passion for great typography and it's all about adding text to photo with style... | Read more »
Hungry Shark Evolution Celebrates Shark...
Shark Week is almost here, as is Independence Day, so naturally Hungry Shark Evolution is going to get in on the action. Yes, even the fireworks. [Read more] | Read more »
The New Trivia Crack Will Feature a Musi...
It's official: iHeartMedia (you may know them from iHeartRadio) will be in charge of providing music-related questions for Trivia Crack's upcoming sequel. Also Trivia Crack is getting a sequel. [Read more] | Read more »
Toca Life: City (Education)
Toca Life: City 1.0 Device: iOS Universal Category: Education Price: $2.99, Version: 1.0 (iTunes) Description: Welcome to Toca Life: City, a metropolis filled with everyday fun! Customize characters, explore exciting locations and... | Read more »

Price Scanner via MacPrices.net

OtterBox Releases New Symmetry Series Metalli...
Otterbox’s new Symmetry Series of smartphone cases flaunts the best of both both street style and street smarts with their new metallic finishes and trusted OtterBox protection for iPhone 6 and... Read more
MacBook Airs on sale for up to $75 off MSRP
Save up to $75 on the purchase of a new 2015 13″ or 11″ 1.6GHz MacBook Air at the following resellers. Shipping is free with each model: 11" 128GB MSRP $899 11" 256GB... Read more
Apple’s Education discount saves up to $300 o...
Purchase a new Mac or iPad at The Apple Store for Education and take up to $300 off MSRP. All teachers, students, and staff of any educational institution qualify for the discount. Shipping is free,... Read more
Save up to $600 with Apple refurbished Mac Pr...
The Apple Store has Apple Certified Refurbished Mac Pros available for up to $600 off the cost of new models. An Apple one-year warranty is included with each Mac Pro, and shipping is free. The... Read more
Mac Pros on sale for up to $260 off MSRP
B&H Photo has Mac Pros on sale for up to $260 off MSRP. Shipping is free, and B&H charges sales tax in NY only: - 3.7GHz 4-core Mac Pro: $2799, $200 off MSRP - 3.5GHz 6-core Mac Pro: $3719.99... Read more
Save up to $400 on 2014 15-inch Retina MacBoo...
B&H Photo has previous-generation 2014 15″ Retina MacBook Pros on sale for up to $400 off original MSRP. Shipping is free, and B&H charges NY sales tax only: - 15″ 2.2GHz Retina MacBook Pro... Read more
15-inch Retina MacBook Pros on sale for up to...
B&H Photo has new 2015 15″ Retina MacBook Pros on sale for up to $125 off MSRP including free shipping plus NY sales tax only: - 15″ 2.2GHz Retina MacBook Pro: $1899.99 $100 off - 15″ 2.5GHz... Read more
College Student Deals: Additional $100 off Ma...
Take an additional $100 off all MacBooks and iMacs at Best Buy Online with their College Students Deals Savings, valid through July 11, 2015. Anyone with a valid .EDU email address can take advantage... Read more
Apple refurbished Time Capsules available for...
The Apple Store has certified refurbished Time Capsules available for $100 off MSRP. Apple’s one-year warranty is included with each Time Capsule, and shipping is free: - 2TB Time Capsule: $199, $100... Read more
Newsweek Launches iPhone App
The venerable weekly news magazine Newsweek, owned by IBT Media, has announced the launch of its first iPhone app. The new app is available through Apple’s App Store and will allow consumers to read... Read more

Jobs Board

*Apple* TV Live Streaming Frameworks Test En...
**Job Summary** Work and contribute towards the engineering of Apple 's state-of-the-art products involving video, audio, and graphics in Interactive Media Group (IMG) at Read more
Project Manager, WW *Apple* Fulfillment Ope...
…a senior project manager / business analyst to work within our Worldwide Apple Fulfillment Operations and the Business Process Re-engineering team. This role will work Read more
Senior Data Scientist, *Apple* Retail - Onl...
**Job Summary** Apple Retail - Online sells Apple products to customers around the world. In addition to selling Apple products with unique services such as iPad Read more
*Apple* Music Producer - Apple (United State...
**Job Summary** Apple Music seeks a Producer to help shepherd some of the most important content and editorial initiatives within the music app, with a particular focus Read more
Sr. Technical Services Consultant, *Apple*...
**Job Summary** Apple Professional Services (APS) has an opening for a senior technical position that contributes to Apple 's efforts for strategic and transactional Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.