TweetFollow Us on Twitter

Blanking
Volume Number:2
Issue Number:2
Column Tag:Basic School

Asm Utility Speeds Screen Blanking

By Dave Kelly, Engineer, General Dynamics, MacTutor Editorial Board

For those that remember Professor Mac's Screen Pokes presented in the April 1985 issue of MacTutor, we discussed the Macintosh screen and how to poke the screen to all blank. The method presented there was very slow. Until such time as someone comes out with a MS BASIC compiler most routines will be slow. MacTutor now has a call out to anyone that has a complier for MS BASIC to step forward and become famous. Please contact us if you have any information to give us about compiled BASIC.

This month we will provide the alternative screen poke method using a library written in 68000 code. These routines were designed to work with the 512K or 128K versions of the Macintosh, however, the code may be modified to be used with other memory sizes.

If you are unfamiliar with BASIC libraries then we recommend that you refer to the BASIC School article in the November 1985 MacTutor on Building a Machine Language Library routine. (Back issues are available). The listings that follow are assembled in the same manner as discussed in that column.

There are three code routines that you need to be concerned with. The LIBinit.asm (Listing 1) routine may be found on page 44 of the Nov. 85 MacTutor. The second routine stores $FFFFFFFF in all screen locations, thus blacking out the entire screen. The third routine inverts all of the screen locations. We thank Serge Rostan of Pontoise, France for contributing the main code for the invert routine.[If you have some good ideas on Basic, please write Dave care of MacTutor and see them in print. -Ed]

The BlankScreen routine (Listing 2) is accessed by the statement: CALL BlankScreen (memory%) where memory% is the memory of your particular system (i. e. use memory%=512 or memory%=128). This routine works fine for 512K or 128K Macs, but you will have to change the equates for Screen512 and/or Screen128 (see listing 2) in order to accomodate other memory sizes. The equates 'GetNextLibArg', 'IntegerArg' and 'BasicError' are BASIC routines defined in BMLL (Microsoft's Building Machine Language Libraries) which library routines may call. The BlankScreen routine reads the memory% parameter and determines the screen location. Then each location is loaded with $FFFFFFFF and the screen is blank. The routine then returns back to the calling program.

The InvertScreen routine (Listing 3) works much the same as the BlankScreen routine. You may call the routine with the statement: CALL InvertScreen (memory%). The passed integer variable memory% is the same as in the BlankScreen routine. The only difference in this routine is that each memory location is exclusive-ored with the value $FFFFFFFF.

Listing 4 and 5 are the Linker and Resource complier files needed by the MDS system to create the library resource file. See Nov 1985 MacTutor for details on how to us these files.

The Screen Demo program in listing 6 demonstrates the use of the BlankScreen and InvertScreen routines. It is advisable but not mandatory that you hide the cursor using HIDECURSOR before blanking or inverting the screen. The cursor may be turned on again with the SHOWCURSOR statement. If the cursor is not disabled then the 16 X 16 cursor location will not be blanked or inverted properly. These libraries may be used to create special effects in your program such as flashing the screen.

Expanding BASIC using library routines greatly improves the capabilities of your programs. If you have a favorite library routine, please send it to us. We would like to share more libraries with other useful purposes.


LISTING 1
;LIBinit routine (See MacTutor Nov. 1985 pg. 44 for comments)
;save as LIBinit.asm

LIBVER_Result  EQU 6
LIBinit:
 CLR.W  LIBVER_Result(a0)
LIBinitExit:
 MOVEQ  #0,d0
 RTS


LISTING 2
; BASIC BlankScreen Library Source Code
; By Dave Kelly
; MacTutor 1985

;Synopsis:
;CALL BlankScreen (memory%)
;Output:

GetNextLibArg  EQU $2A
IntegerArgEQU  $32
BasicErrorEQU  $42
Screen512 EQU  ((512-128)*1024)+108288
Screen128 EQU  108288

 
 JSR  GetNextLibArg(a5) ;Get the next argument
 JSR  IntegerArg(a5) ;[d3:w] = integer error if arg
 ;can't be forced into an 
 ;integer.
 CMP.W  #128,d3
 BEQ  Do128 ;branch if 128K memory
 CMP.W  #512,d3
 BEQ  Do512 ;branch if 512K memory
Device_Unavailable:
 MOVEQ  #68,d2   ;Device Unavailable error
 JSR  BasicError(a5)
Do512:
 LEA  Screen512,A0
 BRA  Blank
Do128:
 LEA  Screen128,A0
Blank:
 MOVE.W #5472-1,d1 ;setup high screen address
 MOVE.L #$FFFFFFFF,d0;move to d0
Loop:
 MOVE.L d0,(A0)+ ;set screen address to d0
 DBRA d1,Loop
 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    
LISTING 3
; BASIC InvertScreen Library Source Code
; By Dave Kelly
; MacTutor 1985
;save InvertScreen.asm

;Synopsis:
;CALL InvertScreen ( memory%)
;Output:

GetNextLibArg  EQU $2A
IntegerArgEQU  $32
BasicErrorEQU  $42
Screen512 EQU  ((512-128)*1024)+108288
Screen128 EQU  108288

 
 BSR  GetIntegerVar;integer arg in [d3:w]
 CMP.W  #128,d3
 BEQ  Do128 ;branch if 128K memory
 CMP.W  #512,d3
 BEQ  Do512 ;branch if 512K memory
Device_Unavailable:
 MOVEQ  #68,d2   ;Device Unavailable error
 JSR  BasicError(a5)
Do512:
 LEA  Screen512,A0
 BRA  Invert
Do128:
 LEA  Screen128,A0
Invert:
 MOVE.W #5472-1,D1
 MOVE.L #$FFFFFFFF,D0
Loop:
 EOR.L  D0,(A0)+
 DBRA D1,Loop
 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    
LISTING 4
;Screen Library Link
;MacTutor 1986

/OUTPUT ScreenLib
LIBinit.Rel
<
InvertScreen.Rel
<
BlankScreen.Rel
$

LISTING 5
ScreenLib.Rsrc
BLIB
TYPE CODE = GNRL
LIBinit,1
.R
ScreenLib CODE 1

TYPE CODE = GNRL
InvertScreen,2
.R
ScreenLib CODE 2

TYPE CODE = GNRL
BlankScreen,3
.R
ScreenLib CODE 3
LISTING 6
'Screen Demo
'By Dave Kelly
'©MacTutor 1986

LIBRARY "Screen Demo"
mem%=128:IF FRE(0)>75000! THEN mem%=512
GOSUB Setmenubar
MENU ON
ON MENU GOSUB menucheck
loop: GOTO loop
menucheck:
    menunumber=MENU(0):IF menunumber<>6 THEN RETURN
    menuitem=MENU(1):MENU
    ON menuitem GOSUB Blank,invert,Flash,Demo,Quit
    Setmenubar:
        MENU RESET  ' Re-do menu bar
        MENU 6,0,1,"Program Menu"
        MENU 6,1,1,"Blank Screen"
        MENU 6,2,1,"Invert Screen"
        MENU 6,3,1,"Flash Screen"
        MENU 6,4,1,"Demo"
        MENU 6,5,1,"Quit"
RETURN
Blank:
HIDECURSOR
CALL BlankScreen(mem%)
SHOWCURSOR
RETURN

invert:
HIDECURSOR
CALL invertScreen(mem%)
SHOWCURSOR
RETURN

Flash:
HIDECURSOR
FOR i=0 TO 100
CALL invertScreen(mem%)
NEXT
SHOWCURSOR
RETURN

Demo:
WINDOW CLOSE 1
GOSUB Blank
WINDOW 1,"",(42,90)-(475,300),3
PRINT "Click here"
WHILE MOUSE(0)<>1:WEND
GOSUB invert
WHILE MOUSE(0)<>1:WEND
GOSUB invert:CLS:GOSUB invert
WINDOW 2,"",(102,140)-(410,240),3
PRINT "Click here"
WHILE MOUSE(0)<>1:WEND
GOSUB invert
WHILE MOUSE(0)<>1:WEND
GOSUB invert:CLS:GOSUB invert
WINDOW 3,"",(152,165)-(360,215),3
PRINT "Click here"
WHILE MOUSE(0)<>1:WEND
GOSUB invert
WHILE MOUSE(0)<>1:WEND
GOSUB invert:CLS:GOSUB invert
GOSUB invert
PRINT SPC(4);"Please make selection":PRINT SPC(5);"from menus above!"
RETURN

Quit:
FOR i=1 TO 4
    WINDOW CLOSE i
NEXT i
MENU RESET:LIBRARY CLOSE
CLS:END
 

Community Search:
MacTech Search:

Software Updates via MacUpdate

Apple Remote Desktop Client 3.9 - Client...
Apple Remote Desktop Client is the best way to manage the Mac computers on your network. Distribute software, provide real-time online help to end users, create detailed software and hardware reports... Read more
Art Text 3.2.2 - $49.99
Art Text is graphic design software specifically tuned for lettering, typography, text mockups and various artistic text effects. Supplied with a great variety of ready to use styles and materials,... Read more
WhatRoute 2.0.15 - Geographically trace...
WhatRoute is designed to find the names of all the routers an IP packet passes through on its way from your Mac to a destination host. It also measures the round-trip time from your Mac to the router... Read more
Sparkle 2.1.1 - $79.99
Sparkle will change your mind if you thought building websites wasn't for you. Sparkle is the intuitive site builder that lets you create sites for your online portfolio, team or band pages, or... Read more
Dash 4.0.1 - 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
TextSoap 8.3.2 - Automate tedious text d...
TextSoap can automatically remove unwanted characters, fix up messed up carriage returns, and do pretty much anything else that we can think of to text. Save time and effort. Be more productive. Stop... Read more
Apple Remote Desktop 3.9 - Remotely cont...
Apple Remote Desktop is the best way to manage the Mac computers on your network. Distribute software, provide real-time online help to end users, create detailed software and hardware reports, and... Read more
Paragraphs 1.1.4 - Writing tool just for...
Paragraphs is an app just for writers. It was built for one thing and one thing only: writing. It gives you everything you need to create brilliant prose and does away with the rest. Features... Read more
Amazon Chime 4.0.5528 - Amazon-based com...
Amazon Chime is a communications service that transforms online meetings with a secure, easy-to-use application that you can trust. Amazon Chime works seamlessly across your devices so that you can... Read more
Apple Final Cut Pro X 10.3.2 - Professio...
Apple Final Cut Pro X is a professional video editing solution.Completely redesigned from the ground up, Final Cut Pro adds extraordinary speed, quality, and flexibility to every part of the post-... Read more

Blasty Bubs is a colorful Pinball and Br...
QuickByte Games has another arcade treat in the works -- this time it's a mishmash of brick breaking and Pinball mechanics. It's called Blasty Bubs, and it's a top down brickbreaker that has you slinging balls around a board. [Read more] | Read more »
Corsola and Heracross are the new region...
Generation 2 finally launched in Pokémon GO, unleashing a brand new batch of Pokémon into the wild. Even before the update went live people were speculating on how to catch elusive Pokémon like the legendary "dogs", Unknown, and whether or not... | Read more »
The Warlock of Firetop Mountain (Games)
The Warlock of Firetop Mountain 1.0 Device: iOS Universal Category: Games Price: $4.99, Version: 1.0 (iTunes) Description: An epic adventure through a mysterious mountain filled with monsters, magic and mayhem! “...it looks downright... | Read more »
Fantasy MMORPG MU Origin’s receives a hu...
Developer Webzen are looking to take their highly popular fantasy battler MU Origin to the next level this month, with its most ambitious overhaul yet. The latest update introduces the long sought after Server Arena, new treasure dungeons, and much... | Read more »
RPG Djinn Caster (Games)
RPG Djinn Caster 1.0.0 Device: iOS Universal Category: Games Price: $4.99, Version: 1.0.0 (iTunes) Description: SPECIAL PRICE 38% OFF(USD 7.99 -> USD 4.99)!!!A Fantasy Action RPG of far foreign lands! Summon the Djinns and rise to... | Read more »
Alto's Odyssey gets its first trail...
There's finally video evidence of Alto's Odyssey, the follow up to the 2015 App Store hit, Alto's Adventure. It looks just as soothing and atmospheric as Alto's last outing, but this time players will be journeying to the desert. Whereas Alto's... | Read more »
Last week on Pocket Gamer
What’s going on in the wider world of portable gaming? Each week we ask that question of our sister website Pocket Gamer. The PG team covers iOS gaming, just like 148Apps, but it also strays into the world of Android games and handheld consoles... | Read more »
Pokémon GO Generation 2 evolution guide
At long last, Niantic Labs finally unleashed the Generation 2 Pokémon into the wild. Pokémon GO trainers are scrambling to grab up this new set of 80 Pokémon. There are some special new tricks required to catch all of these new beasties, though.... | Read more »
The best new games we played this week
It feels as though the New Year got off to a creaking start as far as mobile games go, but that's changed over the past few weeks. The last few days alone have seen the debut of a number of wonderful games, so we thought we'd take the time to... | Read more »
Recruit more scallywags and discover new...
Get ready to show off your sea legs all over again in Oceans & Empires’ new grand update, which aims to make the act of rising to the role of seven seas ruler even more fresh and appealing, thanks to a richness of new content on both iOS and... | Read more »

Price Scanner via MacPrices.net

27-inch Apple iMacs on sale for up to $200 of...
B&H Photo has 27″ Apple iMacs on sale for up to $200 off MSRP, each including free shipping plus NY sales tax only: - 27″ 3.3GHz iMac 5K: $2099.99 $200 off MSRP - 27″ 3.2GHz/1TB Fusion iMac 5K: $... Read more
15-inch 2.2GHz Retina MacBook Pro on sale for...
Amazon has 2015 15″ 2.2GHz Retina MacBook Pros (MJLQ2LL/A) available for $1849.99 including free shipping. Apple charges $1999 for this model, so Amazon’s price is represents a $150 savings. Read more
Apple refurbished iPad Air 2s available start...
Apple has Certified Refurbished iPad Air 2 WiFis available for starting at $319 including free shipping. A standard Apple one-year warranty is included: - 16GB iPad Air 2 WiFi: $319 $60 off original... Read more
Apple refurbished iPad Pros available for up...
Apple has Certified Refurbished 9″ and 12″ Apple iPad Pros available for up to $160 off the cost of new iPads. An Apple one-year warranty is included with each model, and shipping is free: - 32GB 9″... Read more
Apple restocks refurbished 2015 and 2016 13-i...
Apple has Certified Refurbished 2015 and 2016 13″ MacBook Airs available starting at $759. An Apple one-year warranty is included with each MacBook, and shipping is free: - 2016 13″ 1.6GHz/8GB/128GB... Read more
13-inch 2.5GHz MacBook Pro (Apple refurbished...
Apple has Certified Refurbished 13″ 2.5GHz MacBook Pros (MD101LL/A) available for $829, or $270 off original MSRP. Apple’s one-year warranty is standard, and shipping is free: - 13″ 2.5GHz MacBook... Read more
QuickerTek Announces 5TB Apple AC AirPort Tim...
QuickerTek Inc. has announced their new 5TB hard drive upgrade for Apple’s AC AirPort Time Capsule. By customer request, this upgrade also features six external antennas and offers the highest... Read more
Apple Certified Refurbished iMacs available f...
Apple has Certified Refurbished 2015 21″ & 27″ iMacs available for up to $350 off MSRP. Apple’s one-year warranty is standard, and shipping is free. The following models are available: - 21″ 3.... Read more
Apple offering Certified Refurbished Series 1...
Apple is now offering Certified Refurbished Series 1 and Series 2 Apple Watches for 14-16% off MSRP, starting at $229. An Apple one-year warranty is included with each watch. Shipping is free: Series... Read more
1.4GHz Mac mini on sale for $449, save $50
B&H Photo has the 1.4GHz Mac mini on sale for $50 off MSRP including free shipping plus NY sales tax only: - 1.4GHz Mac mini: $449 $50 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
Manager *Apple* Systems Administration - Pu...
Req ID 3315BR Position Title Manager, Apple Systems Administration Job Description The Manager of Apple Systems Administration oversees the administration and 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
Manager *Apple* Systems Administration - Pu...
Req ID 3315BR Position Title Manager, Apple Systems Administration Job Description The Manager of Apple Systems Administration oversees the administration and Read more
*Apple* Technician - nfrastructure (United S...
Let’s Work Together Apple Technician This position is based in Portland, ME Life at nfrastructure At nfrastructure, we understand that our success results from our Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.