14:19
Description: Consider blocks of data as shown in following array:
0x1f5c,
0xfffa, 0xcc2a, 0xaaa9
In the following Assembly Language 8086 programming
example, a routine named rotateNibble is written that takes the data
array and its size as input parameters and pushes the least significant nibble
of all elements in the array in a clockwise manner as shown below:
0xc1f5,
0xafff, 0xacc2a, 0x9aaa
[org 0x0100]
jmp
main
rotateNibble:
push bp
mov bp , sp
push ax
push bx
push cx
push si
mov bx , [bp+6] ;BX=address
of the data
mov cx , [bp+4] ;CX=size
of the data
mov si , 0
rotate:
mov ax , [bx+si] ;AX= an element from data
ror ax , 4 ;rotates it 4 times
mov [bx+si] , ax ;store the result back to data
add si , 2 ;point SI to the next element of data
loop
rotate
pop si
pop cx
pop bx
pop ax
pop bp
ret 4 ;return
empty stack
main:
mov bx ,
data
push bx
mov ax , [size]
push ax
call
rotateNibble
mov ax , 0x4c00
int 0x21
size: dw 6
data: dw 0x1f5c, 0xfffa, 0xcc2a, 0xaaa9,0x1234,0x0110
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