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
 
AAPL
$104.83
Apple Inc.
+1.84
MSFT
$45.02
Microsoft Corpora
+0.64
GOOG
$543.98
Google Inc.
+11.27

MacTech Search:
Community Search:

Software Updates via MacUpdate

Delicious Library 3.3.2 - Import, browse...
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
Art Text 2.4.8 - Create high quality hea...
Art Text is an OS X application for creating high quality textual graphics, headings, logos, icons, Web site elements, and buttons. Thanks to multi-layer support, creating complex graphics is no... Read more
Live Interior 3D Pro 2.9.6 - Powerful an...
Live Interior 3D Pro is a powerful yet very intuitive interior designing application. View Video Tutorials It has every feature of Live Interior 3D Standard, plus some exclusive ones: Create multi... Read more
The Hit List 1.1.7 - Advanced reminder a...
The Hit List manages the daily chaos of your modern life. It's easy to learn - it's as easy as making lists. And it's powerful enough to let you plan, then forget, then act when the time is right.... Read more
jAlbum Pro 12.2.4 - Organize your digita...
jAlbum Pro has all the features you love in jAlbum, but comes with a commercial license. With jAlbum, you can create gorgeous custom photo galleries for the Web without writing a line of code!... Read more
jAlbum 12.2.4 - Create custom photo gall...
With jAlbum, you can create gorgeous custom photo galleries for the Web without writing a line of code! Beginner-friendly, with pro results Simply drag and drop photos into groups, choose a design... Read more
ExpanDrive 4.1.7 - Access remote files o...
ExpanDrive builds cloud storage in every application, acts just like a USB drive plugged into your Mac. With ExpanDrive, you can securely access any remote file server directly from the Finder or... Read more
OmniOutliner Pro 4.1.3 - Pro version of...
OmniOutliner Pro is a flexible program for creating, collecting, and organizing information. Give your creativity a kick start by using an application that's actually designed to help you think. It'... Read more
Evernote 5.6.2 - 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
OmniOutliner 4.1.3 - Organize your ideas...
OmniOutliner is a flexible program for creating, collecting, and organizing information. Give your creativity a kick start by using an application that's actually designed to help you think. It's... Read more

Latest Forum Discussions

See All

Toca Boo (Education)
Toca Boo 1.0.2 Device: iOS Universal Category: Education Price: $2.99, Version: 1.0.2 (iTunes) Description: BOO! Did I scare you!? My name is Bonnie and my family loves to spook! Do you want to scare them back? Follow me and I'll... | Read more »
Intuon (Games)
Intuon 1.1 Device: iOS Universal Category: Games Price: $.99, Version: 1.1 (iTunes) Description: Join the battle with your intuition in a new hardcore game Intuon! How well do you trust your intuition? Can you find a needle in a... | Read more »
Ravenous Rampage (Games)
Ravenous Rampage 1.0 Device: iOS Universal Category: Games Price: $.99, Version: 1.0 (iTunes) Description: | Read more »
Partia 2 (Games)
Partia 2 1.0.1 Device: iOS Universal Category: Games Price: $5.99, Version: 1.0.1 (iTunes) Description: Partia 2 is a SRPG (Strategy Role-playing) video game inspired by Fire Emblem and Tear Ring Saga series. In a high fantasy... | Read more »
Puzzle to the Center of the Earth Review
Puzzle to the Center of the Earth Review By Campbell Bird on October 23rd, 2014 Our Rating: :: SPELUNKING PUZZLESUniversal App - Designed for iPhone and iPad Do some puzzles to make some platforms in this smart and fun free-to-play... | Read more »
Sleep Attack TD Review
Sleep Attack TD Review By Jennifer Allen on October 23rd, 2014 Our Rating: :: A TRUE TWISTUniversal App - Designed for iPhone and iPad Sleep Attack TD is a tower defense game with a difference – you can rotate the layout – and it’s... | Read more »
Mecanic (Education)
Mecanic 1.0 Device: iOS Universal Category: Education Price: $1.99, Version: 1.0 (iTunes) Description: Plates, screws, wheels ... Everything you need to achieve whatever you want... MECHANICWith 'MECANIC' kids will have fun... | Read more »
Earn Your Master Camper Badge in Camp Po...
Earn Your Master Camper Badge in Camp Pokemon Posted by Jessica Fisher on October 23rd, 2014 [ permalink ] Universal App - Designed for iPhone and iPad | Read more »
Garruk Gets His Revenge in a New Magic 2...
Garruk Gets His Revenge in a New Magic 2015 Expansion, Coming This November Posted by Jessica Fisher on October 23rd, 2014 [ permalink ] | Read more »
Sentinels of the Multiverse Review
Sentinels of the Multiverse Review By Rob Thomas on October 23rd, 2014 Our Rating: :: SENTINELS ASSEMBLEiPad Only App - Designed for the iPad Greater Than Games’ tabletop classic, Sentinels of the Multiverse swoops in to save the... | Read more »

Price Scanner via MacPrices.net

Save up to $125 on Retina MacBook Pros
B&H Photo has the new 2014 13″ and 15″ Retina MacBook Pros on sale for up to $125 off MSRP. Shipping is free, and B&H charges NY sales tax only. They’ll also include free copies of Parallels... Read more
Apple refurbished Time Capsules available sta...
The Apple Store has certified refurbished Time Capsules available for up to $60 off MSRP. Apple’s one-year warranty is included with each Time Capsule, and shipping is free: - 2TB Time Capsule: $255... Read more
Textilus New Word, Notes and PDF Processor fo...
Textilus is new word-crunching, notes, and PDF processor designed exclusively for the iPad. I haven’t had time to thoroughly check it out yet, but it looks great and early reviews are positive.... Read more
WD My Passport Pro Bus-Powered Thunderbolt RA...
WD’s My Passport Pro RAID solution is powered by an integrated Thunderbolt cable for true portability and speeds as high as 233 MB/s. HighlightsOverviewSpecifications Transfer, Back Up And Edit In... Read more
Save with Best Buy’s College Student Deals
Take an additional $50 off all MacBooks and iMacs at Best Buy Online with their College Students Deals Savings, valid through November 1st. Anyone with a valid .EDU email address can take advantage... Read more
iPad Air 2 & iPad mini 3 Best Tablets Yet...
The new iPads turned out to be pretty much everything I’d been hoping for and more than I’d expected.”More” particularly in terms of a drinking-from-a-firehose choice of models and configurations,... Read more
Drafts 4 Reinvents iOS Productivity App
N Richland Hills, Texas based Agile Tortoise has announced the release of Drafts 4 for iPhone and iPad. Drafts is a quick capture note taking app with flexible output actions. Drafts 4 scales from... Read more
AT&T accepting preorders for new iPads fo...
AT&T Wireless is accepting preorders for the new iPad Air 2 and iPad mini 3, cellular models, for $100 off MSRP with a 2-year service agreement: - 16GB iPad Air 2 WiFi + Cellular: $529.99 - 64GB... Read more
Apple offering refurbished Mac Pros for up to...
The Apple Store is offering Apple Certified Refurbished 2013 Mac Pros 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
Select MacBook Airs $100 off MSRP, free shipp...
B&H Photo has 2014 a couple of MacBook Airs on sale for $100 off MSRP. Shipping is free, and B&H charges NY sales tax only. They also include free copies of Parallels Desktop and LoJack for... Read more

Jobs Board

*Apple* Solutions Consultant - Apple Inc. (U...
…important role that the ASC serves is that of providing an excellent Apple Customer Experience. Responsibilities include: * Promoting Apple products and solutions Read more
Senior Event Manager, *Apple* Retail Market...
…This senior level position is responsible for leading and imagining the Apple Retail Team's global event strategy. Delivering an overarching brand story; in-store, Read more
*Apple* Solutions Consultant (ASC) - Apple (...
**Job Summary** The ASC is an Apple employee who serves as an Apple brand ambassador and influencer in a Reseller's store. The ASC's role is to grow Apple Read more
Project Manager / Business Analyst, WW *Appl...
…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
*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.