; THIS CODE HAS BEEN TESTED AND IS FULLY OPERATIONAL.

; Problem Statement: Write X86/64 ALP to perform overlapped block transfer (WITHOUT string specific instructions). Block containing data can be defined in the data segment.

; Code from Microprocessor (SPPU - Second Year - Computer Engineering - Content) repository on KSKA Git: https://git.kska.io/sppu-se-comp-content/Microprocessor/


; BEGINNING OF CODE
%macro print 2		; Defined macro for printing messages 2 stand for the parameters
mov rax,1					; For system write specifier
mov rdi,1					; Standard output
mov rsi,%1
mov rdx,%2
syscall
%endmacro

section .data
m1 db 10,"source block",10,13		; 10 stands for new line and 13 stands for tab
m1len equ $-m1

m2 db 10,"destination block after transfer:",10,13
m2len equ $-m2

space db "  "
spacelen equ $-space

srcblk db 10h,20h,30h,40h,50h		; srcblk defined for the functioning
count equ 05h										; count initialized to 5

section .bss
ans resb 4			; ans block is defined for storing the transformed value of the numbers from hexa to ascii
dstblk resb 5		; dstblk is our destination block

section .text			; This section is necessary for assembler understanding
global _start
_start:
print m1,m1len                      
mov rsi,srcblk		; rsi now points to the first location of the source block
call disp_block		; Calling the procedure for displaying the source block

print m2,m2len

mov rsi,srcblk		; Now the rsi points to the source block 
mov rdi,dstblk		; Now the destination pointer points to the first memory location of the destination block
mov rcx,02				; rcx is the register used for the counter purpose  

s1: mov al,[rsi]
mov [rdi],al
inc rsi
inc rdi
loop s1
mov rsi,srcblk
mov rcx,03

s2:  mov al,[rsi]
mov [rdi],al
inc rsi
inc rdi
loop s2

mov rsi,dstblk
call disp_block

mov rax,60
xor rdi,rdi
syscall

disp_block:
mov rbp,count

back:
mov al,[rsi]
push rsi
call disp_8
print space,1
pop rsi
inc rsi
dec rbp
jnz back
ret

disp_8:
mov rsi,ans

mov bl,al
mov dl,bl
rol dl,04
and dl,0fh
cmp dl,09h
jbe add30
add dl,07h

add30:
add dl,30h
mov [rsi],dl
inc rsi

mov dl,bl
and dl,0fh
cmp dl,09h
jbe add130
add dl,07h

add130:
add dl,30h
mov [rsi],dl

print ans,2
ret
; END OF CODE