Run-length encoding: Difference between revisions
→{{header|8086 Assembly}}
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Decoded value is aaaaahhhhhhmmmmmmmuiiiiiiiaaaaaa
</pre>
=={{header|8086 Assembly}}==
Output is in hexadecimal but is otherwise correct.
<lang asm> .model small ; 128k .exe file
.stack 1024 ; load SP with 0400h
.data ; no data segment needed
.code
start:
mov ax,@code
mov ds,ax
mov es,ax
mov si,offset TestString
mov di,offset OutputRam
cld
compressRLE:
lodsb
cmp al,0 ;null terminator?
jz finished_Compressing ;if so, exit
push di
push si
mov cx,0FFFFh ;exit after 65536 reps or the run length ends.
xchg di,si ;scasb only works with es:di so we need to exchange
repz scasb ;repeat until [es:di] != AL
xchg di,si ;exchange back
pop dx ;pop the old SI into DX instead!
pop di
push si
sub si,dx
mov dx,si
pop si
;now the run length is in dx, store it into output ram.
push ax
mov al,dl
stosb
pop ax
stosb ;store the letter that corresponds to the run
dec si ;we're off by one, so we need to correct for that.
jmp compressRLE ;back to start
finished_Compressing:
mov bp, offset OutputRam
mov bx, 32
call doMemDump ;displays a hexdump of the contents of OutputRam
mov ax,4C00h
int 21h ;exit DOS
TestString byte "WWWWWWWWWWWWBWWWWWWWWWWWWBBBWWWWWWWWWWWWWWWWWWWWWWWWBWWWWWWWWWWWWWW",0
OutputRam byte 256 dup (0)
end start</lang>
{{out}}
<pre>
0C 57 01 42 0C 57 03 42 .W.B.W.B
18 57 01 42 0E 57 00 00 .W.B.W..
00 00 00 00 00 00 00 00 ........
00 00 00 00 00 00 00 00 ........
</pre>
The hexdump above converts to: <code>12W 1B 12W 3B 24W 1B 14W</code>
=={{header|Ada}}==
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