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

Bookends 12.5.8 - Reference management a...
Bookends is a full-featured bibliography/reference and information-management system for students and professionals. Access the power of Bookends directly from Mellel, Nisus Writer Pro, or MS Word (... Read more
Chromium 44.0.2403.125 - Fast and stable...
Chromium is an open-source browser project that aims to build a safer, faster, and more stable way for all Internet users to experience the web. Version 44.0.2403.125: This release contains a number... Read more
iMazing 1.2.2 - Complete iOS device mana...
iMazing (was DiskAid) is the ultimate iOS device manager with capabilities far beyond what iTunes offers. With iMazing and your iOS device (iPhone, iPad, or iPod), you can: Copy music to and from... Read more
Audio Hijack 3.2.0 - Record and enhance...
Audio Hijack (was Audio Hijack Pro) drastically changes the way you use audio on your computer, giving you the freedom to listen to audio when you want and how you want. Record and enhance any audio... Read more
FontExplorer X Pro 5.0.1 - Font manageme...
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
Calcbot 1.0.2 - Intelligent calculator a...
Calcbot is an intelligent calculator and unit converter for the rest of us. Featuring an easy-to-read history tape, expression view, intuitive conversion, and much more! Features History Tape -... Read more
MTR 5.0.0.1 - The Mac's oldest and...
MTR (was MacTheRipper)--the Mac's oldest and smartest DVD-backup app--is now updated to version 5.001 MTR -- the complete toolbox, not a one-trick, point-and-click extractor. MTR is intended for... Read more
LibreOffice 4.4.5.2 - Free, open-source...
LibreOffice is an office suite (word processor, spreadsheet, presentations, drawing tool) compatible with other major office suites. The Document Foundation is coordinating development and... Read more
Adobe Lightroom 6.1.1 - Import, develop,...
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
File Juicer 4.41 - Extract images, video...
File Juicer is a drag-and-drop can opener and data archaeologist. Its specialty is to find and extract images, video, audio, or text from files which are hard to open in other ways. It finds and... Read more

Pac-Man Championship Edition DX has brou...
Bandai Namco has released Pac-Man Championship Edition DX on iOS and Android, which features the classic arcade gameplay that we've all grown to love. Pac-Man Championship Edition DX can be enjoyed in much shorter bursts than the arcade versions... | Read more »
Cosmonautica (Games)
Cosmonautica 1.1 Device: iOS Universal Category: Games Price: $6.99, Version: 1.1 (iTunes) Description: Cast off! Are you ready for some hilarious adventures in outer space? | Read more »
Rescue humanity from a Demon horde in An...
Angel Stone is Fincon's follow up to the massively successful Hello Hero and is out now on iOS and Android. You play as a member of The Resistance, a group of mighty human warriors who have risen up in defiance of the Demon horde threatening to... | Read more »
Gallery Doctor (Photography)
Gallery Doctor 1.0 Device: iOS iPhone Category: Photography Price: $2.99, Version: 1.0 (iTunes) Description: Free up valuable iCloud and iPhone storage with Gallery Doctor, the only iPhone cleaner that automatically identifies the... | Read more »
You Against Me (Games)
You Against Me 1.0 Device: iOS Universal Category: Games Price: $.99, Version: 1.0 (iTunes) Description: A simple game… You. Me. Claim, steal, lock, score, win! | Read more »
Yep, it's True - Angry Birds 2 is O...
The not exactly rumors were true and the birds are back. Angry Birds 2 has come to the App Store and the world will... well I suppose it'll still be the same, but now we have more bird-flinging options! [Read more] | Read more »
You Could Design Your Own Card for Chain...
If you've ever wanted to create your own item, weapon, trap, or even monster for Chainsaw Warrior: Lords of the Night, this is your chance. Auroch Digital is currently holding a contest so that fans can fight to the death (not really) to see which... | Read more »
Bitcoin Billionaire is Going Back in Tim...
If you thought you managed to buy everything there is to buy in Bitcoin Billionaire and make all the money, well you though wrong. Those of you who made it far enough might remember investing in time travel - and it looks like that investment is... | Read more »
Domino Drop (Games)
Domino Drop 1.0 Device: iOS Universal Category: Games Price: $1.99, Version: 1.0 (iTunes) Description: Domino Drop is a delightful new puzzle game with dominos and gravity!Learn how to play it in a minute, master it day by day.Your... | Read more »
OPERATION DRACULA (Games)
OPERATION DRACULA 1.0.1 Device: iOS Universal Category: Games Price: $5.99, Version: 1.0.1 (iTunes) Description: 25% off launch sale!!! 'Could prove to be one of the most accurate representations of the Japanese bullet hell shmup... | Read more »

Price Scanner via MacPrices.net

Sale! 13-inch MacBook Pros on sale for $100 o...
B&H Photo has 13″ MacBook Pros on sale for $100 off MSRP. Shipping is free, and B&H charges NY sales tax only: - 13″ 2.5GHz/500GB MacBook Pro: $999.99 save $100 - 13″ 2.7GHz/128GB Retina... Read more
Sale! Save $100 on 13-inch MacBook Airs this...
B&H Photo has the 13″ 1.6GHz/128GB MacBook Air on sale for $899.99 including free shipping plus NY tax only. Their price is $100 off MSRP, and it’s the lowest price available for this model.... Read more
Worldwide Tablet Market Decline Continues, Ap...
The worldwide tablet market declined -7.0% year-over-year in the second quarter of 2015 (2Q15) with shipments totaling 44.7 million units according to preliminary data from the International Data... Read more
TP-LINK TL-PA8030P KIT Powerline Featuring Ho...
Consumer and business networking products provider TP-LINK is now shipping its TL-PA8030P KIT AV1200 3-Port Gigabit Passthrough Powerline Starter Kit that expands your home’s network over its... Read more
Apple refurbished iPad Air 2s available for u...
The Apple Store has Apple Certified Refurbished iPad Air 2s available for up to $140 off the price of new models. Apple’s one-year warranty is included with each model, and shipping is free: - 128GB... Read more
Updated Apple iPad Price Trackers
We’ve updated our iPad Air Price Tracker and our iPad mini Price Tracker with the latest information on prices and availability from Apple and other resellers. Read more
Apple refurbished 2014 13-inch 128GB MacBook...
The Apple Store has Apple Certified Refurbished 2014 13″ MacBook Airs available starting at $759. An Apple one-year warranty is included with each MacBook, and shipping is free: - 13″ 1.4GHz/128GB... 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

Jobs Board

Executive Administrative Assistant, *Apple*...
…supporting presentation development for senior leadership. * User experience with Apple hardware and software is preferred. Additional Requirements The following list Read more
*Apple* Bus Company is now hirin - Apple Bus...
Apple Bus Company is now hiring school bus drivers in the Pettis County area. Class B CDL preferred. Free training provided. No nights or weekends required. Flexible Read more
*Apple* Certified Mac Technician - Updated 6...
…and friendly, hands-on technical support to customers troubleshooting and repairing Apple /Mac products with courtesy, speed and skill. Use your problem-solving skills Read more
Infrastructure Engineer - *Apple* /Mac Envir...
…a part of a team Requires proven problem solving skills Preferred Additional Apple Certified System Administrator (ACSA) Apple Certified Technical Coordinator (ACTC) Read more
*Apple* Retail - Multiple Positions (US) - A...
Job Description: Sales. Specialist - Retail Customer Service and Sales. Transform 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.