Jump to Subroutine & Jump Return instruction on DLX Program

Jump to Subroutine & Jump Return instruction on DLX Program

Example code

Jal subroutine name

Sub routine

Jr r31 to return to main program

Example Jump to Subroutine & Jump Return instruction on DLX Program 

  .start main ;Start program and jump to label main  
 main:       
 jal calculator;jump and link to calculator  
 halt ; halt program after executing calculator sub routine  

 calculator: ;calculator sub routine  
 add r1,r2,r3  
 jr r31 ;back to main method and execute halt statement  

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Unconditional Jump on DLX Program

Jump Instruction used for skipping some portion of sequential program

Jump instruction can be used conditional statements like IF,While,For

Example Jump DLX code 1

 j End;Jump to label End  
 add r1,r2,r3  ;Skip this command  
 End  ;label end  
 jr r31  

Example Jump DLX code 2

 add r1,r1,r2  
 j end;Jump to end label  
 sub r1,r0,r1 ;Never gets here...  
 subi r2,r2,2  
 end addi r1,r1,1  

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