# Assembly Program to sort array of number using AT&T syntax
# Author : Ayush Mishra, Roll Number : 1501CS16

# Data directive : initialize data section
.data
  arr : .quad 25,35,99,24,5,1,13,42,34
  num : .space 8
  msg : .string " "
  nline : .string "\n"

# Text directive : Executable code Section
.text
.globl _start

_start:
  movq $9,%rcx                    #rcx <- 9 contain no. of element in array
  movq $0,%rdx                    #rdx <- 0 contain offset of various element

  sort :                          #sort for sorting array
    movq arr(,%rdx),%rax          #rax <- arr+rdx
    decq %rcx
    movq %rdx,%rdi
    movq %rdx,%rsi
    cmpq $0,%rcx                  #checking whether we reach end of array
    je printloop                  #if equal print

      min:                      #min for finding minimum from rest of array
        addq $8,%rdi
        cmpq $72,%rdi             #if reach end of array
        jge swap
        cmpq %rax,arr(,%rdi)      #if this element less than current minimum
        jl assign
        jmp min

   swap :                         #swap function move minimum element to current index
    movq arr(,%rdx),%rax
    movq arr(,%rsi),%rbx
    movq %rax,arr(,%rsi)
    movq %rbx,arr(,%rdx)
    addq $8,%rdx
    jmp sort                      #jump to sort function again

   assign:                        #this label assign minimum to rax
     movq %rdi,%rsi
     movq arr(,%rdi),%rax
     movq %rdi,%rbx
     jmp min


    printloop :                      #this label print every element of sorted array
      xorq %rcx,%rcx
      movq $0,num
      gameon :
        movq $1, %rax                 # syscall for write
        movq $msg, %rsi               # moving buffer to rsi
        movq $1, %rdi                 # stdout
        movq $1, %rdx                 # length of string
        syscall
        movq num,%rcx
        movq arr(,%rcx),%rax          #move element to be printed to rax
        addq $8,%rcx
        movq %rcx,num
        cmpq $80,%rcx
        jge bye                       #if all element is printed jump to exit
        jmp print

    print:                            # print label to print integer using stack
      xorq %rsi, %rsi                 # rsi reg will contain number of digit in integer

        loop2:                        # loop that push each digit in stack from last to front
        movq $0, %rdx
        movq $10, %rbx
        idivq %rbx                    # rax <- rax/rbx && rdx <- rax % rbx
        addq  $48, %rdx               # converting digit to char
        pushq %rdx                    # push digit in stack
        incq %rsi                     # increment digit count
        cmpq $0, %rax                 # compare rax with zero
        jz   next                     # if zero jump to next label
        jmp loop2                     # else jump to loop label again

        next:                         # this label extract each digit from stack and print
        cmpq $0, %rsi                 # print until result is not printed
        je   gameon
        decq %rsi
        movq %rsi,%rbx
        movq $1, %rax                 # syscall for write
        movq %rsp, %rsi               # moving buffer to rsi
        movq $1, %rdi                 # stdout
        movq $1, %rdx                 # length of string
        syscall                       # call to interrupt to print
        movq %rbx,%rsi
        addq $8, %rsp                 # rsp <- rsp + 8
        jmp  next

   bye:                               # label for exit
        movq $1, %rax                 # syscall for write
        movq $nline, %rsi             # moving buffer to rsi
        movq $1, %rdi                 # stdout
        movq $1, %rdx                 # length of string
        syscall
    movq $60,%rax                     # syscall for exit
    movq $0, %rbx
    syscall                           # calling interrupt to exit