; rle_soln.asm
; sample program to demonstrate decompressing RLE  

include 'emu8086.inc'

org  100h; set location counter to 100h

jmp CodeStart

DataStart:
   ; this is the run length encoded data
   ; notice that it is a list of words (bytes)
   ; with a zero on the end
    rleData dw 1, 4, 3, 9, 5, 3, 2, 7, 0
    
    space db ' ', 0

CodeStart:

   ; put the address of the first rle value in bx
    mov bx, offset rleData
                            
   ; start a loop that will visit each value in rle data
    LoopStart:
    
   ; compare value in list with zer0
    cmp [bx], 0
    
   ; if value was zero, must be end of list so quit
    je EndLabel:
    
   ; move value in list to ax
   ;Moves bx into cx
    mov cx, [bx]
   ;Adds 2 to bx
    add bx, 2
   ;Moves bx into ax
    mov ax, [bx]
    
   ;InnerLoop is used to jump if cx is greater than 0
    InnerLoop:
    
   ; print it
    call print_num
    
   ; print a space
    mov si, offset space
    call print_string
    
   ;Decrement cx by 1
    sub cx, 1
    
   ;Compare cx to 0
    cmp cx, 0            
    
   ;Jumps to InnerLoop if cx is greater than 0
    jg InnerLoop:
    
   ; add 2 bytes to the address in bx to move to the
   ; next value in the list
    add bx, 2  
    
   ; continue the loop until a zero is found
    jmp LoopStart
    
    EndLabel:
    ret
    
DEFINE_PRINT_STRING    
DEFINE_SCAN_NUM
DEFINE_PRINT_NUM
DEFINE_PRINT_NUM_UNS  

   mov cx, [bx]     ; Get run length encoding
   mov ax, [bx+2]; Get replicated value
   add bx,4