Overlapped Block Data Transfer in NASM[x86/64 architecture]

Problem Statement: Write X86/64 ALP to perform overlapped block transfer. Block containing data can be defined in the data segment.

 

%macro print 2

mov rax,1

mov rdi,1

mov rsi,%1

mov rdx,%2

syscall

%endmacro

%macro accept 2

mov rax,0

mov rdi,0

mov rsi,%1

mov rdx,%2

syscall

%endmacro

SECTION .data

msg1: db "Enter quantity of numbers: "

len1: equ $-msg1

msg2: db "Enter numbers in the array: ",10

len2: equ $-msg2

msg3: db "Numbers in the original position: ",10

len3: equ $-msg3

msg4: db "Numbers in the new position(overlapped): ",10

len4: equ $-msg4

msg5: db 10

len5: equ $-msg5

msg6: db "   "

len6: equ $-msg6

SECTION .bss

array1 resb 100

num: resb 3

n: resb 3

adr: resb 16

count: resb 2

cnt: resb 2

count1: resb 2

count2: resb 2

count3: resb 2

count4: resb 2

ol: resb 2

SECTION .text

global main

main:

print msg1,len1

accept num,3

call asc_hex

mov byte[count1],bl

mov byte[count2],bl

mov byte[count3],bl

mov byte[count4],bl

mov byte[ol],bl

shr [ol],1

print msg2,len2

mov r9,array1

array_input:

   accept num,3

   call asc_hex

   mov [r9],bl

   inc r9

   dec byte[count1]

   jnz array_input

print msg3,len3

mov r14,array1

call hex_asc

mov bl,byte[count4]

mov byte[count3],bl

dec r14

loop1:

mov dl,[r14]

mov r10,r14

add r10,[ol]

mov [r10],dl

dec r14

dec byte[count2]

jnz loop1

mov r14,array1

add r14,[ol]

print msg4,len4

call hex_asc

;mov r14,array2

;call hex_asc

mov rax,60

mov rdi,1

syscall

asc_hex:

mov ch,02

mov bl,00

mov r10,0

loop:

    mov al,[num+r10]

    cmp al,61H

    jb next

    sub al,57H

    jmp next2

next:

    cmp al,41h

    jb next1

    sub al,37H

    jmp next2

next1:

     sub al,30H

next2:

     shl bl,04H

     add bl,al

     inc r10

     dec ch

     jnz loop

ret

hex_asc:

mov al,[r14]

;mov [n],al

mov r15,n

mov byte[count],2

l1:

    rol al,04H

    mov dl,al

    and dl,0FH

    cmp dl,09H

    jbe l2

    add dl,07H

    l2:

    add dl,30H

     mov[r15],dl

     inc r15

    dec byte[count]

    jnz l1

print n,2

print msg6,len6

mov byte[cnt],16

mov rbx,r14

mov r11,adr

ll1:

    rol rbx,04H

    mov dl,bl

    and dl,0FH

    cmp dl,09H

    jbe ll2

    add dl,07H

    ll2:

     add dl,30H

    mov [r11],dl

    inc r11

    dec byte[cnt]

    jnz ll1

print adr,16

inc r14

dec byte[count3]

print msg5,len5

jnz hex_asc

ret

Output

amodi@ubuntu:~/MIL/Assign2$ nasm -f elf64 -l overl.lst overl.asm
amodi@ubuntu:~/MIL/Assign2$ ld -o overl overl.o
ld: warning: cannot find entry symbol _start; defaulting to 00000000004000b0
amodi@ubuntu:~/MIL/Assign2$ ./overl
Enter quantity of numbers: 05
Enter numbers in the array:
12
23
34
45
22
Numbers in the original position:
12   000000000060044C
23   000000000060044D
34   000000000060044E
45   000000000060044F
22   0000000000600450
Numbers in the new position(overlapped):
12   000000000060044E
23   000000000060044F
34   0000000000600450
45   0000000000600451
22   0000000000600452