Write X86/64 ALP to count number of positive and negative numbers from the array.

                                                    Savitribai Phule Pune University
                            Second Year of Computer Engineering (2015 Course)
                                                     210257: Microprocessor Lab
                                                                Assignment No. 1 

Problem Statement: Write X86/64 ALP to count number of positive and negative numbers from the array.

;*************************************************************
section .data

nline db 10,10
nline_len equ  $-nline

arr dd  -11111111H, 22222222H, -33333333H, -44444444H, -55555555H
arr_size equ 5

pmsg db   10,10,"The no. of Positive elements in 32-bit array:"
pmsg_len equ $-pmsg

nmsg  db  10,10,"The no. of Negative elements in 32-bit array:"
nmsg_len equ $-nmsg

;*************************************************************
section  .bss

p_count  resq   01
n_count  resq   01
dnumbuff resb   02


%macro display 2
    mov rax,01
    mov rdi,01
    mov rsi,%1
    mov rdx,%2
    syscall
%endmacro

;***********************************************************

section .text
global   _start
_start:

    mov    esi, arr
    mov    ecx,5         ;Arraay counter i.e.5   
    mov    ebx,0;        ; counter for     +ve nos.
    mov    edx,0;        ; counter for    -ve nos.

next_num:
    mov    eax,[esi]    ; take no. in RAX
    rcl    eax,1        ; rotate left 1 bit to check for sign bit
    jc    negative

positive:
    inc    ebx            ; no carry, so no. is +ve
    jmp    next

negative:
    inc    edx            ; carry, so no. is -ve

next:
    add  esi,4                ; 32 bit nos i.e. 4 bytes
    loop next_num

    mov [p_count], ebx        ; store positive count
    mov [n_count], edx        ; store negative count

    display pmsg, pmsg_len
    mov ebx,[p_count]         ; load value of p_count in rax
    call disp8_proc           ; display p_count

    display nmsg, nmsg_len
    mov ebx,[n_count]        ; load value of n_count in rax
    call  disp8_proc         ; display n_count

    display    nline, nline_len

  exit: 
    mov rax,60        ;Exit
    mov rbx,00
    syscall


;**********************************************************
disp8_proc:
    mov edi,dnumbuff    ;point edi to buffer
    mov ecx,02        ;load number of digits to display

dispup1:
    rol bl,4        ;rotate number left by four bits
    mov dl,bl       ;move lower byte in dl
    and dl,0fh      ;mask upper digit of byte in dl
    add dl,30h      ;add 30h to calculate ASCII code
    cmp dl,39h      ;compare with 39h
    jbe dispskip1   ;if less than 39h akip adding 07 more
    add dl,07h      ;else add 07

dispskip1:
    mov [edi],dl     ;store ASCII code in buffer
    inc edi          ;point to next byte
    loop dispup1     ;decrement the count of digits to display
                     ;if not zero jump to repeat

    display dnumbuff,2    
    ret

;****************Output**************************************
;[root@localhost A1]# nasm -f elf64 A1.asm
;[root@localhost A1]# ld -o A1 A1.o
;[root@localhost A1]# ./A1


;The no. of Positive elements in 32-bit array :    01

;The no. of Negative elements in 32-bit array :    04

;[root@localhost A1]#