Programmists - Algorithm.

 PROGRAMMING DYNAMIC PROGRAMS            
 ---------------------------------------------------   
                                                                
(C) Mythos                                                      
                                                                
 Without making a long introduction and description of the procedure I wanted
6s say that the term "dynamic program" is not
most likely some standard reference definition, a
taken by me due to my inability to name this type of program
somehow different.                                              
    Such programs and procedures exist and are used in demos.
The point of such programs is to create, change and destroy themselves in
real time, resulting in amazing savings
address and disk space.  In demos this is a creation
procedures nepe6pocku sprites and screens, tables (which, I think
,can also be attributed to one of the aspects of this type
programming).  In principle, this is also used in games.
Procedures, code creators, or tables do not need more
speed, and memory savings are noticeable, which I think should
entailentails more intensive study of this issue and
widespread introduction of dynamic programming technologies
into programs created today. What I hope is being done now
on the Spectrum stage.   
    And now a little about makers (mactepax, as you wish). I
I'll try to classify them.                                   
 1. disposable                                               
 2.reusable                                              
    It is impossible to attribute any to one or the other
certain procedures, the only difference is that after
execution of the first type of procedure, the latter must
be destroyed, either itself, or the calling program does it. A
after performing a procedure of type two, the last one remains in memory
for future use.                                  
    It is difficult to give any recommendations in writing certain
procedures, it is absolutely clear that the maker must be
significantly smaller in volume than the procedure being created, and its own
pa6oty naturally finish faster than your heart can manage
take the next shot :)Below is the procedure for creating scrollers in real
time mode, the maker is reusable, but it can be easily converted into
whatever you want.                                                   
    How you can use it:                                 
    Let's say you're writing a text or music editor, and so on.
Naturally, since you are writing a cool editor, you need a fast one
scroller, a fast one, as you know, quickly eats up your memory, a
for the editor you need at least two types of scroller (up/down) yes
This and files are shown beautifully and with a screen scroller, and here it is already
the size of the output window is different :( you need other scrollers (don’t forget that
fast ;-) ) so the maker creates in the memory you specify
the type of scroller you specified with the ones you specified again
parameters. And it does this in less than 1.5 interrupts.      
    If, for example, you are not using a scroller at the moment, then
it is quite possible to use a memory area for which
intended to be used for other needs.  Don't forget to reset
after overwriting it, the Status variable, if you have one of course
you are using.                                                    
 A few variables:                                       
    Status is introduced to be able to recognize what typeThe scroller was last created.                             
    al,alil,as are described along with the code text.                  
    They set the number of lines (pixel/string) for
shift                                                         
    Be careful when specifying the starting shift addresses, as
your program uses scrolling, they must be carefully
calculated and specified.  The procedure only shifts by eight
pixels in any direction and only by the number of characters in width
multiples of 8.                                                   
    If necessary, I can modify it to work with the width
multiple of 2.                                                      
                                                                
    After some minor modifications (when he figures it out) he can
shift by fewer or more pixels only by
verticals.                                                      
                                                                
 A small example of parameters:                                   
                                                                
    It is necessary to shift upward the area (l,h) 16x11 (in
familiar places) initial coordinates of the window (in x,y pixels) (16,17)
line widthshift i=6 i.e. from each standard string
6 pixels are taken for shifting.                           
    Don't try to make a shift here with such parameters that
start coordinate "y" + line_width was 6 times greater than
The next number after "y" is kapthoe 8 in ascending order. It will be terrible
looks and boo6re can hang. Next, the parameters are set,
Let's translate the window coordinates into the screen address, let's call it adr1
there will be a so-called “to” address i.e. where is the shift? Address adr2
(address "from") in this link is considered as the address "to" shifted
down to the familiar place.                                              
 In variables al=h, alil=i, as=2 (as) the number of segments in
line.  segment=8 familiar places in our case - this gives the width
windows = 16 characters.                                                 
    Before calling the makeslu procedure, look at the transformations with
addresses before sending them to registers. Maker will do his job
and feel free to start the scrolling procedure. The name you must enter in
in your program: "scroll"                                 
    Upload, study, write if you find any glitches in it. Although
I checked, but you never know, you can’t keep an eye on everything.                 
                                                                
PROCEDURE:MAMESCRL;ПЕРЕМЕННАЯ STATUS                                              
;ОПРЕДЕЛЯЕТ ТИП МОДА СДВИГА                                     
;Q-НЕОПРЕДЕЛЕН                                                  
;1-LEFT                                                         
;2-RIGHT                                                        
;3-DOWU                                                         
;4-UP                                                           
;ПЕРЕМЕННАЯ STPM                                                
;ЗНАМ EE ОПРЕДЕЛЯЕТ НАПРАВЛЕНИЕ                                 
;ВЫБОРMИ 8-МИ БАЙТНЫХ СЕГМЕНТОВ                                 
;(+) ВПРАВО ;(-) LEFT                                                      
;VALUE - STEP, FIXED = 8                                
;                                                               
;LEXICON OF PROCEDURES:                                            
;FROM-REFERS TO M ADDRESS IN THE EMERGENCY AREA                     
;     ADDRESS OF THE FIRST BYTE IN ITS MOT.                            
;     WILL MOVE                                          
;THE - -//- ,ADDRESS OF THE FIRST BYTE IN IT                          
;     MUDA MOVE BYTE AND3 (FROM)                             
;                                                               
;3AMEAAHUE ABOUT ANGLES SPEAKS ABOUT OMHE SHIFT                       
;T.E. WHERE SHOULD THE ADDRESS BE LOCATED (TO,FROM)                      
;IN MAMOM CORNER OF SHIFT                                       
;                                                               
; FOR THE PROCEDURE TO WORK, IT IS NECESSARY TO SET                         
;SCROLL VARIABLE THIS WILL BE THE ADDRESS IN MOTO-                      
;THE SHIFT PROCEDURE WILL BE CREATED                         
;                                                               
MAMESLR                                 
;MAME SCROLL RIGHT                                 
;SET:                                 
;HL=FROM-7                                                      
;DE=TO+1                                 
;UPPER RIGHT CORNER                                            
        PUSH    ВС                                              
        LD      ВС,Q-8                                          
        LD      A,2;RIGHT                                       
        JR      MAMESCR-12                                      
MAMESLD                                                         
;MAME SCROLL DOWU                                               
;HL=FROM                                                        
;DE=ТО+8                                                        
;НИЖНИЙ ЛЕВЫЙ УГОЛ                                              
        PUSH    ВС                                              
        LD      ВС,8                                            
        LD      (STPM+1),ВС                                     
        LD      ВС,#2515;DEC Н;DEC D                            
        LD      A,3;DOWU                                        
        LD      (STATUS+1),A                                    
        LD      A,#D6;SUB И                                     
        JR      MAMESCR                                         
MAMESLL                                                         
;MAME SCROLL LEFT                                               
;HL=FROM                                                        
;DE=ТО+8                                                        
;ВЕРХНИЙ ЛЕВЫЙ УГОЛ                                             
        LD      A,1;LEFT                            JR      MAMESCR-12                                      
MAMESLU                                                         
;MAME SCROLL UP                                                 
;HL=FROM                                                        
;DE=ТО+8                                                        
;ВЕРХНИЙ ЛЕВЫЙ УГОЛ                                             
        LD      A,4;UP                                          
        PUSH    ВС                                              
        LD      ВС,8                                            
        LD      (STPM+1),ВС                                     
        LD      ВС,#2414;IUC Н;IUC D                            
        LD      (STATUS+1),A                                    
        LD      A,#С6;ADD A,И                                   
MAMESCR                                                         
;СОЗДАЕТ ПРОЦЕДУРУ СMРОЛИНГА                                    
;A-CODE(ADD A,И/SUB И)                                          
;ВС-CODE (IUC Н,IUC D/DEC Н,DEC D)                              
;AL - AMOUUT LIUES(STRIUG) FOR MOVIUG                           
;ALIL-AMOUUT LIUS(PIX)IU LIUE(STRIUG) MOVE                      
;AS-AMOUUT SEGMEUTS IU LIUE.SEG=8 ЗНАКОМЕСТ                     
        LD      (ZMЗ),A                                         
        LD      (ZMЧ),A                                         
        LD      (ZMS),A                                         
        LD(ZMб),A                                         
        LD      A,В                                             
        LD      (ZM1),A                                         
        LD      A,С                                             
        LD      (ZM2),A                                         
        EXX                                                     
        PUSH    ВС                                              
        PUSH    HL                                              
        PUSH    DE                                              
        LD      DE,SCROLL                                       
        LD      HL,STMAЗ                                        
        LD      ВС,4                                            
        LDIR;СОЗДАНИЕ КОДА LD SP,(Q)                            
;АДРЕС С MОTОРОГО ЗАПИСЫВАЕТСЯ КОД                              
        EXX                                                     
AL      LD      В,8                                             
;MОЛИЧEСTВО CTPOM СДВИГАТЬ                                      
        PUSH    ВС                                              
        PUSH    DE                                              
        PUSH    HL                                              
ALIL    LD      В,8                                             
;MОЛИЧEСTВО ПИКСЕЛЬНЫХ ЛИНИЙ                                    
;В CTPOME ИЗ 8-МИ ТАКИХ В СТРОКЕ                                
;ЗНАКОМЕСТ ,СДВИГАТЬ    ;МАКС.=8,МИН=1                                                  
        PUSH    ВС                                              
        PUSH    DE                                              
        PUSH    HL                                              
AS      LD      A,4                                             
;MОЛИЧEСTВО СЕГМЕНТОВ ПО ВОСЕМЬ                                 
;3HAMOMECT В CTPOME ,СДВИГАТЬ                                   
        LD      (STMA1+1),HL                                    
        LD      (STMA2+1),DE                                    
        EXX                                                     
        LD      ВС,14                                           
        LD      HL,STMA1                                        
        LDIR                                                    
;СОЗДАТЬ МОД                                                    
        EXX                                                     
STPM    LD      ВС,Q                                            
;3HAM РЕГ.ВС:(+) ВПРАВО,(-) ВЛЕВО ПО                            
;CTPOME                                                         
        ADD     HL,ВС                                           
        ЕХ      DE,HL                                           
        ADD     HL,ВС                                           
        ЕХ      DE,HL                                           
        DEC     A                                               
        JPUZ,AS+2                                         
        РОР     HL                                              
        РОР     DE                                              
ZM1     IUC     Н                                               
ZM2     IUC     D                                               
        РОР     ВС                                              
        DJUZ    ALIL+2                                          
        РОР     HL                                              
        РОР     DE                                              
;сдвиги адресов на знакомест в заданном направлении             
        LD      A,L                                             
ZMЗ     ADD     A,32                                            
        LD      L,A                                             
        JR      ИС,$+6                                          
        LD      A,Н                                             
ZMЧ     ADD     A,8                                             
        LD      Н,A                                             
        DEC     DE                                              
        LD      A,E                                             
ZMS     ADD     A,32                                            
        LD      E,A                                             
        JR      ИС,$+6                                          
        LD      A,D                                             
ZMб     ADD     A,8                             LD      D,A                                             
        IUC     DE                                              
        РОР     ВС                                              
        DJUZ    AL+2                                            
        EXX                                                     
        IUC     DE                                              
;MEMBER ADRES WHERE STACM IS                                    
        LD      (SCROLL+2),DE                                   
        DEC     DE                                              
        LD      HL,STATUS                                       
        LD      ВС,4                                            
        LDIR                                                    
;СОЗДАТЬ МОД LD SP,Q                                            
        РОР     DE                                              
        РОР     HL                                              
        РОР     ВС                                              
        EXX                                                     
        РОР     ВС                                              
        RET                                                     
STMA1;ШАБЛОН                                                    
        LD      SP,Q                                            
        РОР     HL                                              
        РОР     DE                                              
        РОРВС                                              
        РОР     AF                                              
STMA2   LD      SP,Q                                            
        PUSH    AF                                              
        PUSH    ВС                                              
        PUSH    DE                                              
        PUSH    HL                                              
STMAЗ                                                           
        LD      (Q),SP;ШАБЛОН 2                                 
STATUS                                                          
        LD      SP,Q;ШАБЛОН 3                                   
        RET                                                     
                             
P.S.  if you think a little you can transform this
procedure so that it creates an attribute scroller.  
    Scrollers will pa6otatb faster if this is all
use alternate registers. Then sample at a time
will increase to 16 bytes.                                           
                         
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