; a silly PID displaying program v0.06

%macro  newstr  2
    %strlen cnt%1 %2
    %1:     db %2
%endmacro

%macro  print   1
    mov eax, 4
    mov ebx, 1
    mov ecx, %1
    mov edx, cnt%1
    int 80h
%endmacro

%macro  pidval  2
    mov     eax,%1      ; get PID or PPID
    int     80h
    mov esi,%2+4    ; start here (pointer) esi is faster than ebx?
    call    txtloop
%endmacro

section .data           ; define constants...
    newstr  pids,'pid: '
    pid:    db 0,0,0,0,0
    cntpid: equ 5
    newstr  ppids,'ppid: '
    ppid:   db 0,0,0,0,0
    cntppid: equ 5
    tab:    db 9
    cnttab: equ 1
    foot:   db 10,0
    cntfoot: equ 2

section .bss            ; define variables

section .foo            ; this section can be an arbitrary name, but traditionally it's .text
    global _start       ; this label must be defined...

_start:             ; this label must exist
    mov edi,10      ; for mod 10 later on
    pidval  20,pid
    pidval  64,ppid
    print   pids
    print   pid
    print   tab
    print   ppids
    print   ppid
    print   foot
    mov     eax,1       ; exit
    mov     ebx,0
    int     80h

txtloop:
    cmp     eax,0       ; is eax zero yet?
    jle .finish     ; if it is jump outta here
    mov edx,0       ; assume remainder of zero
    div edi     ; divide by edi and return the remainder (mod) (multiply is faster??)
    add edx,48      ; ascii text please (add 48 or 0x30) one byte per char... not unicode
    mov [esi],dl    ; last character = this value we have just calculated
    dec esi     ; decremement pointer by 1
    jmp txtloop
.finish:
    ret