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shrd instruction and converting integers to ascii

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shrd instruction and converting integers to ascii

May 1st, 2005

I have 2 programs im stuck with at the moment.
In the first one im supposed to use the shrd instruction to shift a variable & get a specific number.

 Help with Code Tags 
 Assembly Syntax (Toggle Plain Text) 
 
title 'exercise 13'
 
.model small
.stack 100h
.386
.data
byte1 db 3Bh  ;after 03h
byte2 db 46h  ;after B4h
byte3 db 0FFh ;after 6Fh
value db ?
.code
main proc
   mov ax,@data
   mov ds,ax
 
   mov bx,0Bh
   mov dl,byte2
   movzx ax,dl
   shrd ax,bx,4   ; ah:1011 0000  al: 0000 0100  (B004h)
   mov bx,ax
   shld ax,bx,4
   and ax,0000000011111111b  ;ah:0000 0000 al: 0100 1011  ; 4Bh (should be B4h)
 
 
   mov dx,06h
   mov bl,byte3
   movzx ax,bl
   shrd ax,dx,4   ;(600Fh)
 
 
   mov cx,4
   L1:
     shr byte1,1  ; 03h
     loop L1
 
   mov ax,4C00h
   int 21h
main endp
end main
title 'exercise 13'

.model small
.stack 100h
.386
.data
byte1 db 3Bh  ;after 03h
byte2 db 46h  ;after B4h
byte3 db 0FFh ;after 6Fh
value db ?
.code
main proc
   mov ax,@data
   mov ds,ax
   
   mov bx,0Bh
   mov dl,byte2
   movzx ax,dl
   shrd ax,bx,4   ; ah:1011 0000  al: 0000 0100  (B004h)
   mov bx,ax
   shld ax,bx,4
   and ax,0000000011111111b  ;ah:0000 0000 al: 0100 1011  ; 4Bh (should be B4h)
   
   
   mov dx,06h
   mov bl,byte3
   movzx ax,bl
   shrd ax,dx,4   ;(600Fh)
   
   
   mov cx,4
   L1:
     shr byte1,1  ; 03h
     loop L1
     
   mov ax,4C00h
   int 21h
main endp
end main

and in the second im supposed to take a decimal number and convert it to individual ascii characters. I've used it with a hexadecimal number because that's all i've got working so far , but I need to do it with a decimal number and that's where im stuck.

 Help with Code Tags 
 Assembly Syntax (Toggle Plain Text) 
 
.model small   ; works but only with hexadecimal 
.stack 100h
.data
packedval dw 3425h
.code
main proc
   mov ax,@data
   mov ds,ax
 
   mov si,0
   mov cx,2
 
   next:
     mov al,byte ptr packedval[si]
     and al,00001111b
     or al,30h 
     mov ah,6
     mov dl,al
     int 21h
     mov al,byte ptr packedval[si]
     and al,11110000b
     shr al,1
     shr al,1
     shr al,1
     shr al,1
     or al,30h
     mov ah, 6
     mov dl,al
     int 21h
     inc si
   loop next
 
   mov ax,4C00h   
   int 21h
main endp
end main
.model small   ; works but only with hexadecimal 
.stack 100h
.data
packedval dw 3425h
.code
main proc
   mov ax,@data
   mov ds,ax
   
   mov si,0
   mov cx,2
   
   next:
     mov al,byte ptr packedval[si]
     and al,00001111b
     or al,30h 
     mov ah,6
     mov dl,al
     int 21h
     mov al,byte ptr packedval[si]
     and al,11110000b
     shr al,1
     shr al,1
     shr al,1
     shr al,1
     or al,30h
     mov ah, 6
     mov dl,al
     int 21h
     inc si
   loop next
   
   mov ax,4C00h   
   int 21h
main endp
end main