Coding - Section for beginner coders.

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|                CODING... | 
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X-treamer/Infotek                         
                         
Section for beginners           
encoders.                  
            
 So, here we are again in our newspaper 
this section... And it is intended for those who 
I just sat down at the assembler and is trying 
write something...                    
Let's move on to something more complex: using 
use of interruptions of the second type. how 
known, every 20 milliseconds processor 
interrupts the execution of instructions and jumps 
refers to a special - “shadow” procedure. 
When IM 1(IM 0) is turned on, this will 
Procedure at 0038h - polling the keyboard - 
ry.  But the Z80 allows you to repurpose it. 
That is  you can write another shadow 
procedure, for example, ST player mu- 
zone.  This can be done in the following way: 
zom:                                      
                                          
1.Procedureinterrupt reassignment:    
      DI ;disable interrupts       
 LD A,DD                             
      LD I,A ;reassign the vector       
               interrupts (reg. I)         
      IM 2 ;start interrupts second
              ;kind.                   
      EI ;enable interrupts       
      RET                                 
                                          
2.At the address DDFF-DEOO (see above reg. A) for- 
address of the interruption handling procedure 
vaniya.  And at this address there will be a problem 
A procedure that saves all registers on 
stack and calls the op-int procedure, and then 
After this, it restores the registers in the 
in military order.  It looks like this 
way:                                  
      PUSH BC ;save all registers     
      PUSH DE ;on stack                   
      PUSH AF                             
      PUSH HL                             
PUSH IX                             
      PUSH IY                             
      CALL play ;call the player   
      [CALL...]                        
      [CALL...]                        
      POP IY ;restore all reg.   
      POP IX ;in reverse order         
      POP HL ;from stack                   
      POP AF                             
      POP DEROR Sun                             
      JP 0038h ;go to keypad polling 
                Vasik's nature :).          
                                          
   This is what the program looks like 
reassigning interrupts.  And now on- 
Lastly, the procedure for the double screen effect is 
to:                                       
 to the address, for example 42240, we load one 
screen, and under the address C000h the second screen and 
type the following procedure:             
                                          
      LD HL,42240                         
      LD DE,16384                         
      LD VS,6912                          
      LDIR ;Transfer the screen from the buffer. 
L1: LD Sun,7FFDh                         
      LD A,23; turn on the first screen  
      OUT (C), A ;at address 4000h        
      HALT ;give a delay until int     
      LD A,31                             
      OUT (C), A; turn on the second screen    
      HALT                                
      JP L1                               
      END                                 
                                          
  The dual screen is ready.  Now for already 
For experienced coders, I suggest the two-equipment effect 
rania+pseudo multicolor:                
                                          
DIL1: LD Sun,7FFDh                         
      LD A,23                             
      OUT (C),A                           
      NOP                                 
      : } 7 zeros                      
      NOP                                 
      LD A,31                             
      OUT (C),A                           
      NOP                                 
      NOP                                 
      JP L1                               
      END                                 
                                          
  And what do you see?! One screen viewing 
rushes through the other without blinking!!! 
The only thing I couldn't do was 
synchronize this effect - lines 
slightly oblique. And now the same effect for 
border:                                  
                                          
      D.I.                                  
L1: LD BC,FEH                           
      LD A,1                              
      OUT (C),A                           
      .... - 7 times                     
      LD A,2                              
      OUT (C),A                           
      NOP                                 
      NOP                                 
      JP L1                               
      ENDThe bands are also poorly synchronized, but 
At least they're not going!!!                          
  Well, you've had enough for this number, come on... 
let's move on to the next section...